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Editor

Marcos V. Goycoolea, M.D., M.S., Ph.D. M i n n e s o t a Ear, H e a d & N e c k Clinic Minneapolis, Minnesota

Co-Editors

Michael M. Paparella, M.D. Minnesota Ear, Mead & Neck Clinic Minnesota

Rick L. Nissen, M.D. M i n n e s o t a E a r , H e a d & N e c k Clinic Minneapolis, Minnesota

ATLAS OF

Otologic Surgery 1989 W.B. SAUNDERS COMPANY Harcourt Brace Jovanovirh, I n c . Philadrlphia ' l^ondon / Toronto Montreal ' Svdnev ' Tokyo

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s a u n company . Brace Jovanovich. Inc. | . f u r t ^ Center dependence Square Wesl u

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Library of Congress Cataloging-in-Publication

PURO CHILE ES TU CIELO AZULADO

Data

PURAS

Alias o f o t o l o g i c s u r g e r y . Bibliography: p. I

R F 2 9 5 . G 6 9 1989

6I7.8TO9

W, II. Saunders Stall l.iz Schweber

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Melissa Walter

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Waller Verbilski

Michelle Maloncy

William Cole

°< Otologic Surgen'

INIOJ

(I-72H- -2J37-

^19H9 by W. B. Saunders Company. Copyright under the Uniform Copyright Conven Simultan. oiisly published in Canada. All rights reserved This hook is protected bv 'Vrighl No part ol it niay be reproduced, stored in a retrieval system, or transmitted in any itterT y _ e a n s . electronic, mechanical, photocopving, recording, or otherwise, without n,.r ' ", " 'rom the publisher. Made in the United Stales of America Library of "8«SS catalog card number N8-1HW9. an

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CRUZAN

TAMBIÉN

(from the Chilean national anthem)

ISBN 0 - 7 2 1 6 - 2 3 3 7 - 9

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A TI. DULCE PATRIA

Ear—Surgery—Aliases. I. P a p a r e l l a , M i c h a e l M. 11 N i s s e n , Kick I.. III. T i t l e . [ D N L M : 1. E a r surgery- aliases. W V 1 7 G 7 2 4 a |

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BRISAS

Y ESE CAMPO DE FLORES BORDADO ES LA COPIA FELIZ DEL EDEN . . .

Govcoolea, Marcos V.

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*» print number:

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Contributors G w e n n Afton, M . S . Medical Illustrator, M i n n e s o t a Ear, H e a d and N e c k Clinic and Beck Visual Communications,

Minneapolis,

Minnesota.

M a r c o s V . Goycoolea, M . D . , M . S . , P h . D . Minnesota Ear, H e a d and N e c k Clinic. Otology Consultant, Chilean Military Hospital and Audia Chile, Santiago, Chile.

Peter Hilger, M . D . , M . S . Assistant Professor,

Department of Otolaryngology,

University of Minnesota.

Staff Physician, St. Paul R a m s e y Medical Center, St. Paul, M i n n e s o t a .

T i m o t h y K. J u n g , M . D . , P h . D . Associate Professor,

Division of Otolaryngology and Head and Neck Surgery,

L o m a Linda University, L o m a Linda, California.

Sherry Lamey Head

technologist,

Otopathology Laboratory,

Department of Otolaryngology,

University of Minnesota.

Alan J . Nissen, M . D . California Ear Institute, Palo Alto, California. Clinical Instructor, Stanford University,

Palo Alto, California.

Rick L. Nissen, M . D . M i n n e s o t a Ear,

Head and Neck Clinic.

Michael M. Paparella, M . D . M i n n e s o t a Ear, and

Head and Neck Clinic. Chairman Emeritus, Clinical Professor,

Director of the Otopathology Laboratory,

Department of Otolaryngology,

University of Minnesota.

Donald Robertson, P h . D . Associate Professor,

D e p a r t m e n t of O t o l a r y n g o l o g y a n d D e p a r t m e n t of Cell

Biology and Neuroanatomy, University of Minnesota.

Kurt Schellhas, M . D . D i r e c t o r o f N e u r o - I m a g i n g , C e n t e r for D i a g n o s t i c I m a g i n g , S t .

Louis Park,

Minnesota.

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Contributors

Robert Smith,

Chief Resident,

M.D.

Department of Otolaryngology,

Motto

University of Minnesota.

Edward W. Szachowicz, M . D . , Ph.D. Assistant Professor,

Department of Otolaryngology,

University of Minnesota.

Staff Physician, St. Paul R a m s e y Medical Center, St. Paul, M i n n e s o t a .

Learn to learn from everything you do and everybody around you.

•

Key Words Anatomy Function Pathogenesis Research Open

mind

Common Dedication

sense

Preface This book is written primarily for physicians in training (residents). It is my aim to make it a dialogue with you, the residents, beginning with the preface itself. T h e origin of this book goes back to my first year of residency in Otolaryngology. Although m a n y good texts w e r e available, 1 felt that I needed a book that went back to basics in clear and understandable language, and that would provide me with the essential concepts from which to start. It s e e m e d to me that a complicated organ such as the ear could be made, at least at that stage, a little simpler (not simple). O v e r time 1 h a v e been thinking of different aspects that 1 felt to be important and useful for this purpose, and 1 asked the different contributors to do the s a l * . Accordingly, we have tried to create a book that emphasizes the basics, rather than o n e that s h o w s our methods. In the s a m e context, this atlas is only intended to complement other texts on the subject. Because this is primarily a conceptual atlas, we have m a d e no attempt to provide detailed discussions of evaluations and indications; such discussions are provided by the works cited in the list of selected references. This list also includes publications that describe essential concepts of a n a t o m y a n d function. Because of the extent of these subjects, the works available number in the thousands; we apologize to, those authors w h o s e important publications are not cited owing to lack of space and request their understanding. We are a w a r e that this first edition will need improvements. It is our h o p e that these will c o m e from your criticisms and suggestions. There are a number of thoughts and general philosophies that 1 believe a r e useful. 1 do not expect you to agree with them but to be exposed to t h e m and think. S o m e of them will make sense, s o m e will not. 1 h o p e that s o m e of the latter will make sense to you in, time. T h e techniques described in "this book are intended to s h o w different a p p r o a c h e s based on the knowledge of anatomy, function, and pathology. They are oriented m o r e toward a w a y of thinking than toward a d o g m a of doing, in the expectation that the surgeon will think of each surgical procedure as a distinct and different act. It is my hope that this will allow the surgeon to vary an a p p r o a c h according to need> habit, or ability at a specific time. 1 believe that there is no single best technique for otologic surgery; in order to achieve a safe and efficient result, different surgeons might select different but equally valid approaches. It is easy to be rigid; it is e v e n successful, on the whole. It is harder to tailor your a p p r o a c h case by case since this requires an overall concept. In the long run, however, it is much m o r e rewarding. Research a n d knowledge of a n a t o m y and pathogenesis permit proper changes and improvem e n t s . Ear surgery can be what you want it to be. If it is to be developed into an art, knowledge, creativity, dynamism, and an open mind, together with c o m m o n sense, a r e essential. As in any discipline, there are basic principles; h o w e v e r , they should be regarded not as rigid rules but rather as underlying philosophies. An essential point to be remembered is that the aim of surgery is to solve problems. Patients c o m e to you for you to solve their problem, not for the surgery itself. In the same context, solving a problem does not m e a n applying formulas or fitting patients into treatment classifications. Classifica-

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XU

Preface

tions and formulas a r e nothing more than c o m m o n sense put on paper—use them as a tool, do not be "ruled by t h e m . " This may s e e m like a subtle concept but it makes all the difference in the world. The difference between operating and solving a problem is like the difference between passing a cloth over a table and cleaning the table. A n o t h e r important concept implied here is what I call the concept of "intent." F o r all actions that are to be translated into an efficient result, there must be the intention of obtaining such a result. This involves the rational use of y o u r senses. W h e n you look through the operating microscope y o u must s e e , observe, analyze, and use the information obtained. This is quite different from "glancing." You must know what you are looking at (based on a n a t o m y ) and the most likely possibilities and alternatives that can be found (based on pathogenesis). It is also essential to understand that surgery is in the mind and the heart and not primarily in the hand. Good hands are important, but they are not enough. A mechanical task can be performed brilliantly by a moron if it is done over and o v e r again in the s a m e fashion. The art of surgery lies as much in the choices as in the act itself, and also in the postoperative care. T h e medical act begins with the first clinical visit and ends when the problem is solved. It is always tempting to simplify o u r lives with what is "usual" and "customary." If you are in pursuit of excellence, avoid this temptation. A c o m m o n attitude of residents (we have all been residents and I have not forgotten the experience) is to proceed as the "books say" or the "journal s a y s . " Books and journals (including this one) do not say anything; they present what different authors believe. Although important and valuable, this information should be treated as a reference, not as d o g m a . On patient evaluation: Despite the fact that the a m o u n t of information available and the precision of laboratory studies have had a great impact on today's medicine, the essential process of evaluation remains u n c h a n g e d . Regardless of the facilities available, the patient's history and examination are as critical as ever. Provided that they are done properly, a diagnosis is reached most of the time based on history and examination alone. For children, the parents (usually the mother) a r e crucial in providing information. Regardless of a mother's background, she is the one w h o spent the night with the sick child a n d provided food, clothing, cleansing, and so on. The mother will not tell you what to diagnose and do, but she will provide important clues for the diagnosis, and at times for treatment. Again, our role is to listen respectfully and learn; then, using our knowledge, diagnose and if possible tench. Laboratory studies confirm impressions, provide documented objective evidence, and rule out or detect problems or lesions not detectable otherwise. Much can be said about this; suffice it to mention that laboratory studies are ordered with specific questions in mind, and should not be ordered if the results are not oriented toward an action to be taken. On the procedure of choice: Apart from strict physiopathology, there are other factors to consider in deciding what benefits an individual most. W h a t is good for s o m e may not be good for others. A procedure that requires frequent checkups might not benefit somebody w h o cannot be checked periodically. People and circumstances vary and so should your solutions. Although it is our duty to c h a n g e attitudes for the better, it is c o m m o n sense to accept that some things cannot be changed. On the risks of surgery: it is important to reiterate that it is the patient w h o takes the risk, not the surgeon. H o w warranted a specific risk is will depend on the patient's situation and needs, and calls for c o m m o n sense on the part of the surgeon. A surgeon should be conservative. Although "everybody has something that can be operated upon," the surgeon's role is to assess

Preface

XIII

if the operation is indicated and really helpful. Conservatism should be a product both of knowledge a n d of profound respect for an individual w h o has trusted you; it should not c o m e from ignorance or inability to perform what is needed. As for doing what other surgeons do successfully, again, their experience should be seen as background and reference a n d not as d o g m a . It is fine to imitate others a n d this should be done by all m e a n s , provided that what is imitated is understood, agreed u p o n , and applicable to your patients. It is important to evaluate a n d rationalize what the leading surgeons do; behind each of the true leading surgeons are m a n y hours of study and hard work. Question positively their m e t h o d s and rationale. Ask yourself what is intended by a specific m e t h o d and w h y . Is it reasonable? Is it the best way? "Trendy" procedures and "state of the art" instruments also require thorough knowledge a n d understanding. They usually have good reasons behind them; you must understand and agree with those reasons. If all you need to do is kill a fly, u s e a 50-cent fly swatter; do not buy a $ 5 0 , 0 0 0 electronic fly killer because it is "state of the a r t . " Trends c o m e and trends g o . U s e c o m m o n sense when investing. Otologic surgery, like medicine itself, is a never-ending learning process. Y o u are never too good to learn from everybody else. Seeking advice is a sign not of weakness but of maturity. Learn to use your senses; observe a n d listen to other surgeons and specialists, the operating team, your patients, and others. Learn positively from those w h o want to help you and from those w h o want to harm or use you. Learn to'Jearn from everything you do and everybody a r o u n d you. Each surgical cas< is different. W h e n placing pressure-equalizing tubes, study the ear canals a n d their contents, the tympanic m e m b r a n e , the middle ear m u c o s a , characteristics of the effusion, and so on. Relate them to o n e another, to the laboratory studies, and to the clinical history. This simple process will enrich you a n d you will learn what you never thought you would. A difficult task is to learn how to accept reality and our lack of true knowledge. As hard as it is to deal with success, it is h a r d e r and d e m a n d s more stamina to deal with failure. Complications and unwanted results do h a p p e n , e v e n if you seemingly have done y o u r job properly. Objective self-assessment and complete revision of the subject should follow every failure, even .if it " w a s bound to h a p p e n . " Y o u m a y easily forget 2 0 0 successful stapedectomies and never forget one case of hearing loss d u e to a reparative granuloma. Y o u must also learn to accept that in m a n y cases in otology, surgery d o e s not t u r n back the disease process, and that different individuals have different responses to similar surgical procedures and different healing capabilities. F r o m this standpoint alone, the results of tympanoplasty m a y vary from 60% to 100%. A 60% success in a population with .poor nutritional background can be better than 90% in one with optimal nutrition. Percentages are relative; your o w n and those of others should be analyzed in their full context. There are m a n y o t h e r points and ideas that 1 would, have liked to discuss here. Some of them are discussed in the text. U A few w o r d s on the contributors to this atlas: Gwenn Afton, the illustrator, has an MS in Medical Illustration from the Medical College of Georgia. I had the privilege of writing the temporal bone dissection manual that she illustrated as her master's thesis. At the time s h e not only performed such dissections herself but requested direct supervision and explanations. In spite of her being by far the youngest m e m b e r of this team, her professionalism, dedication, interest, and talents are what 1 would have expected from an experienced and famed medical illustrator. I worked directly with her on each and every drawing (in all chapters) in this atlas. However, it must be mentioned that the designs for Chapter 1 (Pertinent A n a t o m y ) w e r e selected by Donald Robertson; for the discussions of n e u r o -

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Preface

otology (in C h a p t e r s 5, 17, 18, and 19) by Rick Nissen; and for C h a p t e r 14 (Lasers in Otologic Surgery) by Alan Nissen. We have been asked to lend m a n y of the illustrations (only those designed by G w e n n and m e ) to Michael Paparella for the otology v o l u m e of his forthcoming text. 1 have no doubt that with the appearance of this atlas we are also witnessing the e m e r g e n c e of an artist w h o will be a significant contributor to medical illustration in the coming years. Timothy Jung is my former fellow resident at Minnesota. Tim oriented his research toward biochemistry of the ear and has remained working in this area while practicing primarily clinical otolaryngology. He has contributed directly to the discussions of the Thiersch graft (in Chapter 7) and mastoid obliteration and surgery for complications of suppurative otitis media (in Chapter 1 0 ) , and is wholly responsible for Chapter 8 (External Ear Canal Procedures). His clinical and surgical experience, coupled with his a p p r o a c h toward e a r disease based on a n a t o m y and pathogenesis, m a d e him a natural contributor to this book. Sherry L a m e y has headed the Otopathology Laboratory at the University of Minnesota for 20 years. She is, in my opinion, directly responsible for transforming this laboratory into one of the best, if not the best, of its kind in the world. M a n y generations of residents (including mine) and research fellows have benefited from h e r knowledge and expertise. The histology and histopathology slides in this atlas, as well as C h a p t e r 4 (Temporal Bone Removal), are a l l products of her work. In order to include a solid discussion of the use of lasers in otologic surgery ( C h a p t e r 14), we asked Alan Nissen to be a contributor. Alan trained at the University of Nebraska and took a postdoctoral fellowship with Dr. Michael Glasscock in Tennessee. He is currently a member of the California Ear Institute in Palo Alto, where he has developed expertise in the use of lasers. Rick Nissen is a m e m b e r of our team at the Minnesota Ear Head and Neck Clinic, where he directs the Neuro-otology division. Rick did his residency •it the University of Nebraska and hail his postdoctoral training in N e u r o otology at the House Ear Institute in Los Angeles, lie started as a contributor tn this atlas, but his interest, efficiencv, and understanding of the spirit of the h o o k were such that he also b e c a m e a co-editor of the chapters dealing wholly or in part with ncuro-otologv (Chapters 5, 17, IK. and 19). This section is the product of his work. Michael PaparWI.i was Professor and Chairman of flu' Department ol Olobryngologv at the L'nivcrsitv ot Minnesota for 17 ve.IRS. Under h i s leadership, the department became one ol the primarv otologv centers in the world, both clinically and in research. H i s contributions to our specialty in the last two decades have been a m o n g the most significant by any single individual, a n d his n a m e has a well-deserved place of honor in the historv of otology. In addition, he had the vision and openness to train specialists from all over the world. The results of his teachings and philosophies are becoming more evident every year as his former students gradually reach the highest academic positions both in the United States and abroad. After his retirement as active c h a i r m a n , he developed the Minnesota Ear, Head and Neck Clinic. Clinically m o r e active 'han ever, he has continued doing research as Clinical Professor and Director of t h e Otopathology Laboratory at the University of Minnesota. 1 originally trained with him in Minnesota and have rejoined him at the Minnesota E a r , H e a d and Neck Clinic. W h e n 1 c a m e from Chile to train with him, he opened ' h e doors of the department a n d of his friendship to m e . He has undoubtedly h a d a direct influence on my training; at the same time, he has trained m a n y °f the contributors to this work. It was a privilege for me to have Michael as a » editor of this atlas. c

Preface

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Donald Robertson h a s headed the a n a t o m y course for medical a n d g r a d u a t e students in the Department of Cell Biology and N e u r o a n a t o m y (formerly Department of A n a t o m y ) , and the yearly course in Head and Neck A n a t o m y for otolaryngology residents for 17 y e a r s at the University of Minnesota. Having been his student both as a resident a n d as a g r a d u a t e in a n a t o m y , 1 h a v e appreciated the value of his experience and his teaching. It has been a privilege for me to have him contribute C h a p t e r 1 (Pertinent A n a t o m y ) . Kurt Schellhas has contributed C h a p t e r 3 (Pertinent Concepts in High Resolution Temporal Bone Imaging). Kurt went to medical school, did his residency, and took his neuroradiology fellowship at the University of Minnesota. His experience with and clarification of concepts in diagnostic imaging in otology have been instrumental in this short but conceptual chapter. C h a p t e r 20 (Plastic Surgery of the Pinna) w a s written by Ed Szachowicz, Peter Hilger, and Robert Smith. Ed and Peter trained in Otolaryngology u n d e r Michael Paparella. Ed had postdoctoral training in Plastic Surgery with Drs. William Wright and Russell Kridel in H o u s t o n and Dr. Clyde Litton in Washington, DC. Peter had his postdoctoral training in Plastic Surgery at H a r v a r d Medical School and Massachusetts E y e and E a r Infirmary u n d e r Dr. Richard Webster. Robert is currently a Chief Resident at the Department of Otolaryngology at the University of Minnesota. O t h e r contributors to this atlas a r e Dr. H a m m e d Sajjadi, formerly a Fellow in our clinic ( 1 9 8 6 - 1 9 8 7 ) , w h o assisted with Chapter 6 (Operating R o o m Principles and General C o n c e p t s ) , and Drs. Michael Morris and Richard F o x , currently otology Fellows, w h o served as reviewers and critics. Professor A. Rosales from Santa Cruz, Bolivia, provided me with the diagrams and design of his consistently successful piston wire prosthesis. David Muchow took the scanning electron micrograph of the stapes used on the cover, and Jodi Nielsen, the radiology and vestibular technologist and medical photographer at the Minnesota E a r , Head and Neck C.inic, took the photographs in C h a p t e r 6. The "patients" in this chapter are my children M a r c o s and Hortensia, and t h e nurse is Joanne Eplev, RN, head nurse at our institution. Kay E m e r y typed a n d edited the manuscript and J o y c e Hansen assisted in typing. Gail E. M o w e n assisted Alan Nissen with his chapter. The contributions of grants N « . 5P-50-NS-14538 from the National Institute of Neurological and C o m m u n i c a ' i v e Disorders and No. NS-19433-04 from the Deafness Research Foundation, as well as a grant from the 3M C o m p a n y of Minnesota, a r c acknowledged. A final note: The opinions in this preface, as well as the selection of t h e dedication, key words, and motto, are my o w n and do not necessarily represent the opinions and choices of the contributors to this atlas. M a r c o s V.

G o y c o o l e a , M.D.

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SECTION I

Contents

Basic Anatomic Concepts

C H A P T E R 1 Pertinent A n a t o m y '. Donald Robertson, Ph.D. CHAPTER 2 Marcos V.

Pertinent Histology Goycooha M.D., M . S . , r

1

3

23 Ph.D.

CHAPTER 3 Kurt

Pertinent C o n c e p t s in High Resolution Temporal Bone Imaging Sdwtlhas, M.D.

S E C T I O N II

Temporal Bone Dissection

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37

C H A P T E R 4 Temporal Bone Removal Marcos V. Goycooiea, M.D., M.S., Ph.D. Sherry Lamcy

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C H A P T E R 5 Surgical Procedures Marcos V. Goycoolea, M.D., MS.^Ph.D. Kick L. Nisscrt, M.D.

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S E C T I O N III

99

General Principlel

tin- cvlt-rn.il r.ir

Prominences a n d depressions seen on the e a r , with he exception of the lobule. In addition to the features that are superficially hscemible, the cartilage plate contains other features hat become evident upon removal of overlying skin, "riese include the following (Fig. 1-2/1): 1- The spine of the helix, projecting anteriorly from helix, near the c m s . 2 The tail of the helix (cauda helix), the terminal W i o n of the helix, located at the posteroinferior r g i n of the auricle. 3 The isthmus, the point of continuity between auricular a n d meatal cartilages, located imme'ely posterior to the entrance of the external mean e

n a

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+. The lermmai incisure, between the isthmus and the tragal lamina of the auricular cartilage. Its inferior extremity is the opening of the external meatus. Superiorly it is marked by the anterior incisure. The auricle is attached to the side of the head by the following features: 1. Its continuity with the cartilaginous portion of the external acoustic meatus. 2. The skin covering the ear and continuing onto the skull. The skin of the auricle is tightly bound to the perichondrium of the lateral aspect of the ear but is s o m e w h a t freer on the medial surface. There is very little fat in the subcutaneous tissue of the ear. Except in the tragal a n d antitragal regions, the hair of the auricle is rudimentary. Sebaceous

B

£

Pertinent A n a t o m y

Pertinent A n a t o m y g l a n d s are present on both surfaces and are part i c u l a r l y n u m e r o u s in the concha and triangular fossa.

3 Three extrinsic ligaments. T h e s e include: A. The anterior ligament, extending from the zygoma to the helix and the tragus.

¡ 3 . The superior ligament, extending from the superior margin of the bony meatus to the spine of the helix. C. The posterior ligament, extending from the mastoid process to the concha of the auricle, i. Muscles, consisting of the following: A An extrinsic g r o u p , formed of three small musc l e s (anterior, superior, and posterior) belonging to the facial g r o u p of muscles and supplied by the facial nerve. B. An intrinsic g r o u p of six small muscles, which are extremely variable in their development and have no functional significance in h u m a n s .

The External Acoustic Meatus The external acoustic meatus is a bony-cartilagious c a n a l extending from the concha of the auricle 5 the tympanic membrane. In its adult configuration d e s c r i b e s a slight S-shape, with the lateral cartilaglous portion s o m e w h a t concave anteriorly and inTOirly and t h e medial bony portion slightly concave o s t e r i o r l y and superiorly. Owing to the obliquity of le tympanic membrane, the posterosuperior wall of le m e a t u s is slightly shorter than the anteroinferior •all (approximately 25 mm and 31 m m , respectively), lightly more than half of the external meatus is ntirely bony (medially), with the anterior wall, floor, nd lower posterior wall formed by the tympanic ortion of the temporal bone. Its roof and the upper art of t h e posterior wall are formed by the squamous ortion. The cartilaginous (lateral) portion of the external e a t u s forms a trough-shaped structure that is open i p e r i o r l y and posteriorly. This canal is completed ' h e latter quadrants by the squamous portion of e temporal bone. In addition to being slightly >™ed, it is s o m e w h a t broader in its lateral aspect " e r e it makes up approximately two thirds of the rcumference of the meatus. Medially it makes up " g h l y one third of the meatal wall. At its lateral •tremity the cartilage of the meatus is continuous ' " i that of the auricle through the isthmus; mediy. it articulates with the bony portion of the meaT h e anterior wall is characterized by the presence " fissures (incisures of the cartilaginous m e a t u s 5

h v

or fissures of Santorini), which assist in imparting a limited mobility to the auricle. The major relationships of the meatus are the following (Fig. 1 - 2 B ) : 1. Anteriorly and laterally, the parotid gland. T h e more medial and anterior relationships include the mandibular fossa a n d the condyle of the mandible. 2. Inferiorly, the parotid gland. 3. Superiorly and medially, the epitympanic recess of the middle ear. 4. Posteriorly, the mastoid air cells. The skin lining the external m e a t u s is continuous with that of the auricle, and also forms the external layer of the tympanic membrane. It varies considerably in thickness, being m u c h heavier in the cartilaginous portion of the meatus w h e r e there is a population of large sebaceous glands and numerous fine hairs. The skin of the bony meatus, which is m u c h thinner, is firmly b o u n d to t h e periosteum of the underlying bone and contains a rather sparse p o p u lation of glands and hair cells, located predominately on the superoposterior wall.

7

Mallear prominence

Umbo Ant. mallear told

Para flaccida

P o s t , m a l l e a r told

FIGURE

1-3.

A, Tympanic membrane. B, Vascular supply of the tympanic membrane.

The Tympanic Membrane The tympanic m e m b r a n e (Fig. 1-3/1) is a thin, elliptically shaped m e m b r a n e situated between the medial end of the external meatus and the middle ear cavity. Its vertical axis measures approximately 9 to 10 mm; its horizontal axis measures approximately 8 to 9 m m . In its final adult position the tympanic m e m b r a n e slopes medially from superior to inferior and from posterior to anterior, so that its external (meatal) surface faces somewhat inferiorly and anterolaterally. In the newborn the membrane is situated much more horizontally, but gradually shifts to the adult position with development of the tympanic portion of the temporal bone. The major features of the tympanic membrane, as viewed from the lateral aspect, include the following: 1. T h e umlw, which is the center of the slight lateral concavity. It marks the point of attachment of the tip of the manubrium of the malleus.

2. The malleal stria, extending superiorly and slightly anteriorly from the umbo. It is formed by the manubrium of the malleus. The stria and a perpendicular line extending through the umbo divide the m e m b r a n e into quadrants (anterosuperior, anteroinferior, posterosuperior, and posteroinferior). 3. The mallear prominence, marking the attachment of the lateral process of the malleus to the membrane. Extending from the prominence in anteroinferior and

posteroinferior directions a r e , respectively, the ante-

approximately 0.1 mm thick (combined). These in-

rior and posterior mallear folds.

clude: », 1. An outer cutaneous layer of thin skin, which is continuous with the skin of the external meatus.

4. The purs fensa, that portion of the m e m b r a n e lying below the mallear prominence and the mallear folds and making up the greatest part of the m e m brane. 5. The purs flaccida, that portion of the m e m b r a n e lying above the mallear prominence and the mallear folds. It is n a m e d for its characteristic laxity. Structurally, the m e m b r a n e consists of three layers

2. A middle layer of connective tissue consisting of the following: A. The radiate fibrous layer, m a d e up of fibers radiating peripherally from the u m b o a n d m a nubrium of the malleus. B. T h e circular fibrous layer, m a d e up of concen-

g

;

Pertinent A n a t o m y trically arranged fibers that are most prominent peripherally, w h e r e they thicken to form a fibrocartilage ring or annulus, attaching the m e m b r a n e to the tympanic sulcus of the temporal bone.

3

An inner layer of mucous m e m b r a n e continuous with that of the middle e a r cavity.

Vascular

Supply of the

External Ear

T h e arteries of the external ear originate from s e v e r a l sources. T h e auricle has an abundant blood supply, which is derived primarily from the posterior auricular branch of the external carotid artery a n d the auricular rami arising from the superficial temporal a r t e r y . These are shared by the meatus, which also r e c e i v e s the deep auricular branch of the maxillary artery. T h i s artery passes through the parotid gland to enter e i t h e r the cartilaginous or bony part of the meatus. T h e tympanic m e m b r a n e is supplied on both its lateral and medial surfaces. Laterally, the deep auricular artery forms a small peripheral vascular ring from which small branches radiate onto the memb r a n e . Superiorly, a large vessel, the external descending artery, arises from the vascular ring to descend to the region of the umbo, with a course more or less parallel to the manubrium (Fig. 1-3B). Internally, a s e c o n d peripheral vascular ring is formed primarily

by the stylomastoid branch of the posterior auricular artery and t h e anterior tympanic branch of the maxillary artery. The largest of the vessels arising from this inner

vascular ring is the internal descending artery, which descends on the inner surface of the m e m b r a n e in a course parallel to that of its external counterpart. T h e venous channels draining the structures of Ihe external ear roughly correspond to the arteries of supply. Those draining the auricle and the external

postbranchial region. For this reason, both the cranial; n e r v e s supplying the branchial arches (V, VII, IX, I a n d X) and the cervical nerves m a y be represented; by sensory c o m p o n e n t s . Although there is consid ! erable variation, the approximate sensory D I S T R I B U T ; Hon is as follows (Fig. 1-4): .^

Pertinent A n a t o m y

9

i

1. T h e cervical plexus of nerves ( C 2 - 3 ) , via t h e ' great auricular n e r v e , supplies most of the lateral' surface of the auricle (except for the upper anterior '. portion). T h e lesser occipital nerve from the plexus supplies much of the medial surface of the auricle. 2. The mandibular division of the trigeminal n e r v e , via its auriculotemporal branch, supplies the u p p e r anterior portion of the auricle, the u p p e r and ' anterior walls of the external meatus, and the u p p e r L anterior part of the lateral surface of the tympanic membrane. '

3. The auricular branch of the vagus supplies ap¬ 1

proximately half of the external meatus and lateral surface of the tympanic membrane. Although this nerve is typically described as being of vagal origin, it should be appreciated that branches of VII and IX.! may join it and contribute to the sensory innervation , of the external ear. It is impossible to differentiate ! between the distribution of the components; clinical I studies of herpes zoster indicate that all three may, participate. !

FIGURE 1 - 4 . Innervation of the external ear.

t

T h e distribution of nerves supplying the t y m p a n i c , ! m e m b r a n e is very much like that of the arteries— ' small, peripheral contributions supplying the mar-, gins of the m e m b r a n e while the primary nerves^ descend from the superior aspect of the m e m b r a n e a n d parallel the course of the external descending artery, tending to lie slightly posterior to the vessel. The pars tensa of the membrane is not particularly well supplied with sensory nerves; in contrast, t h e pars flaccida has an extremely rich innervation. > I

The Middle Ear

meatus are the anterior auricular tributaries of the superficial temporal veins and the auricular tributaries the posterior auricular vein. Drainage of the tymP " c m e m b r a n e is both external (via vessels c o m "nicating with veins of the external meatus) and "iternal (via branches paralleling the arteries).

Morphology

\

of

a r

m

innervation of the External Ear

The external ear is a region of transition between originally overlying the branchial area and the

ln

i i

T h e middle e a r , or tympanic cavity, is an irregu-l larly shaped c h a m b e r lying within the temporal bone, i bounded laterally by the squamous and t y m p a n i c ) portions and medially by the petrous portion. Itsgreatest dimensions are in the anteroposterior and j vertical planes, which measure approximately 15 mm . each, while the transverse diameter (between the I medial and lateral walls) varies with location and i ranges from 2 to 6 m m . It is not a confined s p a c e but c o m m u n i c a t e s anteriorly with the nasopharynx i

through the auditory tube a n d posteriorly with the mastoid a n t r u m and air cells. T h e middle e a r c a n be divided into the tympanic cavity proper, which is that portion situated medial to

the tympanic membrane, and the epitympanic recess, the upward extension of the tympanic cavity proper above the level of the tympanic membrane. T h e lateral wall (membranous wall) of the middle ear is formed for the most part by the tympanic m e m b r a n e . Superiorly, within the epitympanic recess this wall is formed by a plate of bone (the scufwrn) derived from the s q u a m o u s portion of the

temporal bone. The head of the malletfe and the body and short process of the incus lie in the epitympanic recess. The roof (tegmental wall) of the middle ear consists of a thin plate of b o n e , the legmen tympani, which separates the epitympanic recess from the cranial cavity. It is traversed by the petrosquamous suture, which persists into adult life in approximately 50% of the population, a n d by small foramina that transmit nerves a n d arteries. The j'oor (jugular wall) is a very narrow, irregular surface lying slightly below the level of the m e a t u s ,

10

Pertinent A n a t o m y

and is formed by a plate of bone separating the cavity f r o m the bulb of the internal jugular vein. If the bulb of the vein is small, the floor may be as much as 8 to 10 mm thick a n d may contain hyporympanic air cells. In contrast, a large bulb may cause the floor to b u l g e u p w a r d into the middle ear. In such cases the floor m a y be imperfect, and the vessel a n d cavity are separated only by the mucosa of the middle ear. The anterior wall (carotid wall) is a very thin, bony septum separating the middle e a r from the carotid c a n a l . Perforations in the plate allow the transmission of nerves a n d vessels from the canal to the middle e a r . Above this is the site of the opening of the

semicanal for the tensor tympani muscle, and immediately inferior to this is the tympanic ostium of the auditory tube, through which the middle ear communicates with the nasopharynx.

The posterior wall (mastoid wall) (Fig. 1-5A) is somewhat triangular, with the narrowest portion s i t u a t e d inferiorly where it is related to a number of tympanic air cells. Superiorly, at the level of the epitympanic recess, the posterior wall is deficient a n d forms the aditus, through which the middle ear communicates with the mastoid antrum. Salient feat u r e s of the posterior wall include the following: 1. The pyramidal eminence, located just below the aditus. At the apex of the eminence is a small a p e r t u r e that transmits the tendon of the stapedius muscle.

2. The iter chordae tympani posterior, a small foram e n immediately lateral to the pyramidal eminence. Through this foramen the chorda tympani nerve e n t e r s the middle e a r . 3. T h e posterior sinus, a small fossa just above the p y r a m i d a l eminence. 4. The fossa of the incus, situated just above the p o s t e r i o r sinus. This marks the point of attachment of t h e posterior ligament of the incus. T h e medial wall (labyrinthine wall), which separates t h e middle ear cavity from the inner e a r , is the m o s t complex of the middle ear boundaries. Its major features are s h o w n in Figure 1-5B: 1. The promontory, a slight elevation formed by ' h e basal turn of the cochlea of the inner ear. Extending inferiorly and posteriorly from the promontory is a slight ridge, the subioiium. More superiorly, r u n n i n g from the posterior aspect of the promontory t o w a r d the. pyramidal eminence, is a second ridge, ' h e ponticulus. The subiculum and, the ponticulus c r e a t e three small depressions on the posterior part t h e medial wall. of

2 T h e fossula fenestrae cochleae (cochlear fossa or round window niche), which is posteroinferior to the Promontory. The lowest of the three depressions of e medial wall, it is b o u n d e d superiorly by the l h

subiculum and is the site of the cochlear window (round window), in which the secondary tympav.c membrane (round window m e m b r a n e ) resides, lie round window and associated membrane may or m a y not be visible, depending upon the size a."id configuration- of the promontory and subiculum.

3. The tympanic sinus, occupying the midc ie depression formed by the subiculum and ponticuf is at the junction of the posterior and medial walls. T> ie extent of the sinus is variable; it may extend fir enough into the petrous portion of the temporal bone to bring it into close relationship to the a m p l 1lary end of the posterior semicircular canal and tl e posterior end of the lateral canal.

4. The fossula fenestrae vestibuli (fossa of the oVil window or "stapes niche"), lying in the superk r depression above the ponticulus. It contains the vestibular (oval) window, w h i c h is closed by the footplate of the stapes and the associated a n n u k r ligament. 5. A slight bony ridge, the prominence of the latere I semicircular canal, which lies high on the posterior aspect of the medial wall in the region of the aditu;. and marks the anterior end of that c o m p o n e n t of the inner ear. ,

6. The prominence of the facial canal, lying above thr\ posterior edge of the promontory a n d the oval win-' d o w , immediately below and parallel to the prominence of the lateral semicircular canal. It runs almost horizontally across the posterior half of the medial wall, then turns to enter the posterior wall. T h e facial n e r v e courses through this canal. 7. The cocWfnri/orm process, located anterosuperiorly on the medial wall. It represents the curved end of the bony semicanal of the tensor tympani muscle.

The

Ossicles

The ossicles form an articulated bony chain that I extends across the middle ear and connects the tympanic membrane with the vestibular window. This chain acts as a bent lever to convert the vibrations of the tympanic m e m b r a n e into intensified thrusts of the stapes against the perilymph. Developmentally, the ossicles arise from three different sources. The first branchial arch of the embryo (mandibular a r c h ) gives rise to the head of the malleus and the long and short process of the incus; the second arch (facial a r c h ) , to the long process of the incus and the stapes. The anterior process of the malleus develops independent of the branchial arches as a m e m b r a n o u s bone.

Pertinent A n a t o m y The major features of t h e malleus include the allowing (Fig. U6A): I A relatively large and h e a v y head lying within the epitympanic recess, which bears on its surface a small facet for articulation with the incus. > A short, s o m e w h a t constricted neck from which three processes arise, including: A. The long and prominent manubrium, the largest of the mallear processes. It is attached to the tympanic membrane and in turn is the site of insertion of the tensor tympani muscle. B. T h e lateral process, which creates t h e mallear prominence of the tympanic m e m b r a n e .

C. The anterior (long) process, a long and delicate bony projection in the fetal malleus. In the adult it is a small bony stump that is the site of attachment of t h e anterior ligament of the malleus. The malleus is s u s p e n d e d by three small ligaments

Fig 1-6B), which include the anterior mallear liganent, extending from the anterior process to the

vmpanosquamous fissure; the superior mallear liganent, extending from the top of the head to the roof

jf the epitympanic recess; and the lateral mallear igament, which runs from the lateral process to the •nargin of the tympanic notch. Also associated with the malleus is the tensor ympani muscle. This muscle arises from the cartilagnous part of the auditory tube, t h e adjacent spheloid bone, and the semicanal situated directly above •he osseous portion of the auditory tube. Its tendon )f insertion passes through the cochleariform proc!ss, turns sharply lateral, and inserts on the manu>rium of the malleus, close to the neck. The muscle icts to draw the manubrium medially, tensing the ympanic m e m b r a n e , and thus serves a protective Hinction. T h e tensor tympani is innervated by a 'ranch of the mandibular division of the trigeminal lerve.

The mews (Fig. 1 - 6 C ) is characterized by the following features: '•• A relatively large body that is deeply indented anteriorly to form an articular facet. •• Two bone processes. These include: A The sliort process, which extends posteriorly from the body. B. The slender long process, extending inferiorly from the body and paralleling the manubrium of the malleus. On the medial side of the very distal extremity of the long process is the small lenticular process, through which the incus articulates with the stapes. Like the malleus, the incus is s u s p e n d e d by small 5'irnents (Fig. I - 6 D ) . These are t h e posterior ligament, " h acts to hold the short process in the fossa of K

the incus, a n d the superior ligament, which extends '< from the body to the roof of the epitympanic recess.'; T h e stapes (Fig. l - 6 £ ) consists of the following: 1. A small, cylindrical head, which articulates with the lenticular process of the incusT * 2. T w o crura (anterior and posterior), which extend from the head. The anterior c m s is s o m e w h a t shorter and straighter than the posterior. 1

3. A thin base (footplate), a flattened plate of b o n e . attached on its end to t h e distal extremities of thec r u r a . It fits into the vestibular window a n d , like thatt structure, has a straight inferior border and a curved^ superior border. The ligamentous support of the stapes is t h r o u g h ; the elastic annular ligament, which attaches to t h e ) margins of the footplate and the vestibular w i n d o w and allows m o v e m e n t of the stapes. Such m o v e m e n t is greatest at the anterior end and upper border of the footplate and very slight posteroinferiorly. It has been stated that loud tones c h a n g e the normal pattern of m o v e m e n t to a rocking motion; this would result in a net d e c r e a s e in the displacement of perilymph, thereby protecting the inner e a r . This c h a n g e presumably is brought about by contraction of the stapedius muscle (Fig. 1 - 6 F ) , which inserts onto t h e posterior crus. As mentioned above, this muscle serves a protective function by preventing excessive excursion of the footplate; it does not m o v e the ossicle unless the ossicular chain is broken. It is innervated by a branch of the seventh nerve. The joints of the ossicular chain are true synovial (diarthrodial) joints with characteristic articular c a p sules. There are t w o such joints within the chain. T h e first is the incudomalleal, between the head of the malleus and the body of the incus. This is a relatively lax joint that allows the m o v e m e n t of the incus to lag behind that of the malleus; as a result, the amplitude of the m o v e m e n t of the bony process of the incus is less than that of the manubrium. The second joint is the incudostapedial, between the lenticular process of the incus and the head of the stapes.

The Auditory (Pharyngotympanic or Eustachian) Tube

T h e auditory tube extends from its tympanic ostium within the anterior wall of the middle ear cavity to its pharyngeal ostium within the nasopharynx. The latter is situated just posterior to the dorsal end of the inferior nasal concha. In the adult the tube is between 30 and 40 mm in length, a n d has a slight S-shaped configuration as it passes obliquely d o w n -

14

Pertinent Anatomy

Pertinent A n a t o m y

w a r d , medial, and anterior from the middle ear to t h e pharynx. The tympanic ostium is roughly 25 mm higher than the pharyngeal ostium in the adult. There are s o m e basic and significant morphologic differences between the auditory tube of the child a n d that of the adult; in the child the tube is shorter a n d relatively wider and more horizontally situated. Structurally, the auditory tube consists of both cartilaginous a n d bony c o m p o n e n t s . The bony portion makes up approximately two thirds of the tube; jt is widest at the tympanic orifice and gradually narrows throughout its length, with its anterior extremity (the isthmus) the most constricted portion of t h e entire tube. In its course the bony tube is lateral to the carotid canal, superior to the jugular fossa. The cartilaginous portion of the tube extends from t h e isthumus to the nasopharynx. It is not totally cartilaginous, however; its lower lateral and inferior w a l l s consist of fibrous connective tissue overlying t h e tensor and levator veli palatini muscles. The lumen of the auditory tube, in the resting state, is a closed, slitlike cavity. The pharyngeal end of the tube strongly resists passage of air from the pharynx to the middle ear. Passage from the tympanic cavity to the pharynx is much easier.

The Mucosal Lining of the Middle Ear

The tympanic cavity is lined throughout hv a thin, transparent, vascular membrane that is continuous w i t h that of the auditory tube anteriorlv and the tympanic antrum and mastoid cells posteriorly. The membrane is tightly bound to the periosteum and a l s o invests the ossicles and their associated ligaments. In reflecting Irom the walls ol the cavitv to the ossicles and their ligaments, the mucous lining forms various folds and pouches; the most important of these a r e the superior vouch (Prussak's pouch), situated medial to the pars flaccida of the tympanic

membrane, and the anterior and posterior vouches (of Troltsch), which are related to the anterior and posterior mallear ligaments respectively.

Vascular Elements Middle Ear

of the

The middle e a r receives blood via a number of small arteries (Fig. 1 - 7 , 4 , 6 ) , which with one excep-

15

tion are derived from the external carotid c its branches. They include;

1. T h e anterior tympanic, a branch of the maxillary artery. It is distributed to the anterior part oi the cavity, including the medial surface of the tympanic membrane, and enters the middle ear by parsing through the petrotympanic fissure.

2. T h e stylomastoid branch of either the posterior auricular or occipital artery. This artery e n t e r s the facial canal and gives rise to the posterior lyn panic artery, which then enters the middle ear in c o r r o a n y with the chorda tympani nerve.

3. The inferior tympanic artery, derived frorii the ascending pharyngeal branch of the external carotid. It accompanies the tympanic branch of nerv? IX through the tympanic canaliculus to gain the middle ear cavity.

4. The superficial petrosal and superior tympanic^ arteries, which are both branches of the middle mr ningeal artery. T h e former runs through the facial canal for a short distance, then pierces the tegmen tym, >ani to enter the middle ear; the latter enters through the petrosquamous fissure. 5 . The atroficutympitmc arteries arise from the i t t e r nal carotid as it passes through the carotid canal; and enter the middle ear by passing through the thin bony lamina separating the carotid canal from the middle ear. The veins of the middle ear parallel the arteries. TUey are tributary to the superior petrosal dural sinus m e t the pterygoid plexus of veins.

Nerves of the Middle Ear ( R R .

\\

U

The major nerve of the middle ear is the lumpttmc 1'iathh vt the gU^>ophan,nytvl iicnr (Jarobson's nerve}. Arising (rom the inferior ganglion of the parent trunk, the tvnipanic nerve enters the tvmpanic catnaliculus through a small foramen located on the crest of the thin plate of bone separating the j u g u h r foramen and the external orifice of the carotid c a m I. O n c e in the middle ear, the nerve forms the tympanic plexus within the mucosa overlying the promontor /. There are two modalities represented in the tympanic nerve/plexus. The greatest portion of the fibers a e sensory; these are distributed to the mucosa of t i e middle e a r , the mastoid air cells, and the audito'y tube. The remaining fibers are parasympathetic and have no function in the middle ear. Instead, they e m e r g e from the upper border of the plexus to pierce the tegmen tympani and run forward on the floor of

FIGURE 1-7 A-B, Arteries of the middle ear.

Sup. tympanic

Petrosal

\d

Pertinent A n a t o m y

Pertinent A n a t o m y

17

I*

Greater petrosal

Geniculate ganglion

of the middle ear to these a r e a s , a basic appreciation of the location a n d extent of pneumatized areas is desirable. Since the mastoid process develops from both petrous and s q u a m o u s portions of the temporal bone, there is a sutural line between the two c o m ponents that normally is obliterated with growth. Occasionally, however, a heavy plate of bone persists between the two portions, forming what has been designated [Corner's septum or the "false bottom." The existence of this septum c a n cause confusion in surgical a p p r o a c h e s through the mastoid process. T h e mastoid process is rather consistently pneumatized (80%), the process usually being completed by the third or fourth year. T h e r e is, h o w e v e r , considerable variation both in its extent a n d in the arrangement of the air cells. Because of this variation, several types are described, including the pneumatized, in which the entire process is occupied by air cells; the diploic, in which the process is occupied by bpne m a r r o w instead of air cells; the mixed type, consisting of a combination of the pneumatized a n d diploic types; a n d the sclerotic or nonpneumatized/ nondiploic process. Owing to the considerable variation in the extent and location of the mastoid cells, several terminologies have been used. T h e position of the sigmoid sinus in the posterior cranial fossa will influence markedly the position or occurrence of all types.

FIGURE 1-8. Nerves of the middle ear.

Caroticotympanic

the middle cranial fossa as the lesser petrosal nerve; ultimately they leave the skull to run with the auriculotemporal branch of V3 and supplv the parotid gland.

1 he middle ear receives sympathetic fibers derived from the internal carotid plexus. These fibers, which n t e r the middle ear along with the caroticotympanic a r t e r i e s , are primarily associated with the vessels of we cavity and have a vasoconstrictive effect. T h e chorda tympani branch of t h e facial nerve enters he middle ear through the iter chordae posterius. P a s s e s forward and down between the manubrium ' *e malleus and the long process of the incus, n e n leaves the cavity by passing through the petrotympanic suture. T h e chorda tympani has no func°n in the middle ear. It contains both parasympaJ l i c fibers supplying the submandibular and ' "lingual glands a n d taste fibers for the anterior t h . r d s of the tongue. After leaving the middle e

0

ear it joins the lingual branch of V3 to be distributed with that nerve. Although they do not enter the middle ear, the nerves to the muscles associated with the ossicles must be mentioned since they are vital to normal function. The nerve to the stapedius muscle is a branch of the facial nerve, and arises from the parent trunk as it descends through the vertical portion of the osseous facial canal. The nerve to the tensor tympani is a branch of the mandibular division of the trigeminal nerve.

Pneumatization of the Temporal Bone The temporal bone exhibits varying degrees of pneumatization. Because of the intimate relationship

Mastoid air cells may invade adjacent areas of the temporal bone. Some of the more frequent extensions form the hy\iotympanic cells, which lie in the plate of bone separating the middle ear cavity from the jugular bulb, a n d the epitympanic cells, which are extensions into the roof of the middle ear. T h e latter g r o u p may be extensive e n o u g h to include cells that will invade the root of the zygomatic arch a n d the squam o u s portion of the temporal bone. T h e petrous apex of the temporal bone (i.e., that part of the petrous portion anterior to the labyrinth) may also be pneumatized, particularly by outgrowths from the tympanic cavity. These cells, the petrous apex cells, are necessarily related to the auditory tube and the carotid canal.

The Facial Nerve in the Temporal Bone

After traversing the internal acoustic meatus a n d passing through the lateral end of that structure, the facial nerve enters the bony facial canal (fallopian canal). This canal continues laterally for a short

distance a n d brings the facial nerve to just above the base of the cochlea, w h e r e it makes a s h a r p turn (the external genii) to run posteriorly. The g e n u is also the site of the. geniculate ganglion of the nerve, which contains the cell bodies of the nerve's sensory c o m ponents. T h e genu and the ganglion are anterolateral to the superior semicircular canal a n d between the vestibule of the inner e a r and the cochlea, a n d c a n be easily localized from the middle ear as a point situated just medial to the tip of the cochleariform process. Continuing posteriorly with a slight inferolateral inclination, the bony canal forms the prominence of the facial canal on the medial wall of the middle ear. This prominence may be large enough to partially cover the oval window and the base of the stapes. T h e lateral wall of the canal in this part is extremely thin a n d m a y be dehiscent. Behind the base of the pyramidal eminence the canal makes a broad turn to descend vertically and somewhat laterally through the mastoid process. In this descending or vertical portion the nerve may have a slight anterior concavity. Relative to the exterior of the skull, the canal normally lies d e e p to the sutural groove between the tympanic and mastoid portions of the temporal bone. It should be remembered that there m a y be marked deviation from this "normal" position, in which case the canal is usually situated more posteriorly. In its course from the brainstem through the facial canal the facial nerve is supplied with blood by small arteries derived from the anteroinferior cerebellar branch of 4 h e basilar artery, the stylomastoid or occipital branches of the external carotid, and the petrosal arteries. T h e r e are apparently no anastomoses b e t i e e n the labyrinthine blood supply a n d these arteries, which seem to anastomose freely with one a n o t h e r . Insufficiency of the vascular supply to the facial nerve, from whatever cause, is regarded by s o m e as one of the primary causes of Bell's palsy.

The Inner Ear T h e inner ear containing the essential cochlear and vestibular mechanisms, lies within the petrous portion of the temporal bone. T h e labyrinth of the inner ear is surrounded by the bony otic capsule, which is a unique structure for several reasons. It is formed from 14 separate centers of ossification that fuse, leaving no sutural lines. These centers, though formed from cartilage, retain no areas of chondral growth. In addition, the bone of the capsule retains its fetal character, that is, typical haversian systems

18

Pertinent A n a t o m y Pertinent A n a t o m y anterior canal and the superior crus of the posterior canal unite to form a single crus. The canals h a v e very definite planes of orientation. The anterior is situated in the vertical plane at an angle of 45 degrees with respect to the sagittal plane of the skull, the posterior crura being m o r e medial. The posterior canal is also in the vertical plane, at 45 degrees with respect to the sagittal plane of the skull (that is, at 90 degrees with respect to the plane of the anterior canal). The lateral canal forms an angle of approximately 30 degrees with the horizontal plane, its anterior end being highest, and is situated in the angle between the anterior and posterior canals. 3. The cochlea, a cone-shaped, hollow, bony spiral of about two and three quarters turns with a relatively broad base and a pointed apex or cupula. Its base lies against the anteromedial surface of the vestibule and the lateral end of the internal auditory meatus. Part of the basal turn of the cochlea forms the promontory of the middle ear. • From its base the axis of the cochlea is directed anterolaterals/ and slightly u p w a r d . The central bony core of the cochlea is the modiolus, through which nerves and vessels travel to attain the structures of the cochlea. From the outer surface of the modiolus the osseous spiral lamina projects into the cavity of the cochlea, partially subdividing the duct. It terminates at the cupular end of the cochlea by projecting slightly beyond the apex of the modiolus. This projecting bony process of the lamina is the hamulus.

never develop. Finally, the capsule's maximum dimensions are attained by the fifth week of intrauterine life. The labyrinth of the inner ear is divided into osseous a n d m e m b r a n o u s c o m p o n e n t s . The osseous labyrinth, a system of bony canals within the otic capsule, consists of three parts: 1. The vestibule, which forms the central portion of the labyrinth; it is a relatively large, ovoid space approximately 4 mm in diameter. Its characteristic features include the following: A. The elliptical recess, located on the floor of the vestibule. It receives the anterior end of the utricular portion of the m e m b r a n o u s labyrinth. B. The spherical recess, located anterior and slightly inferior to the elliptical recess. It is the site of the saccular portion of the membranous labyrinth.

C. The •vestibular whitlow, of the vestibule.

within

the

lateral

w,.ll

D. Small orifices for the passage of nerves to the vestibular portion of the inner ear. These a e found on the medial wall and adjacent flo-•, where the vestibule abuts on the lateral e r d of the internal acoustic meatus. 2.

The semicircular canals, which are continuous with the vestibule. The anterior (superior) canal forms the arcuate eminence on the bonv floor of the middle cranial fossa. The posterior'canal has no externally located landmarks associated with if. Ihe lateral canal, as mentioned above, creates ,i prominence in the region of the aditus of th.middle ear. All of the semicircular canals com municate with the vestibule through both of theicrura. There are only five openings into the ves tibule, however, since the posterior crus of th.

By convention, and for ease of reference and description, the cochlea is described as if it were sitting on its base with the apex pointing directly up. Viewed in this orientation, it can be seen that the spiral lamina is initiating the division of the cochlear duct into an upper chamber, the scala vestibuli, and a lower chamber, the scala tympani. Only the scala vestibuli communicates with the vestibule of the inner ear; it also communicates with the scala tympani at the apex of the duct. The scala tympani ends blindly at the round window (secondary tympanic m e m b r a n e ) of the middle ear. T h e osseous labyrinth is not a closed chamber; there are several areas of communication with the exterior. These include the following: 1. The vestibular aqueduct, extending through the otic capsule from the vestibule to the posterior cranial fossa. Its cranial end lies lateral to the internal acoustic meatus on the posterior surface of the petrous portion of the temporal bone, where it is usually overlaid by a scale of b o n e . This a q u e d u c t transmits the endolymphatic duct and an accompanying vein.

19

2. The cochlear aqueduct, which begins in the scala tympani of the basal coil of the cochlea near the round window. This small canal terminates on the inferior surface of the petrous pyramid, between the jugular fossa and the external orifice of the carotid canal. In the human it is not patent, being filled with connective tissue. 3. The oval window, which is closed by the footplate of the stapes and the associated annular ligament. 4. T h e round window, closed by the secondary tympanic m e m b r a n e . 5. The fissula ante fenestram and the fossula post fenestram, small clefts related to the vestibular wind o w of the lateral wall. The fissula ante fenestram usually extends completely through the bony lateral wall of the vestibule, while the fossula does so in only about 25% of all individuals. Both normally are filled with connective tissue. The fissula is important because of its predilection for otosclerotic bone formation. 6. The orifices of the nerves and vessels attaining the inner ear. Lining the entire osseous labyrinth is a layer of periosteum or endosteum, which is continuous with the periosteum of the cranium through the various apertures and lies in close apposition to the walls of the osseous labyrinth. T h e areas of modification that merit further description occur within the cochlea. At the free edge of the osseous spiral lamina the endosteum is thickened to form the limbus, which then divides into vestibular and tympanic lips separated by a groove, the internal spiral sulcus. The vestibular lip is confluent with the vestibular membrane. The tympanic lip extends from the edge of the osseous spiral lamina across the lumen of the cochlea to the opposing peripheral wall, forming the fibrous basilar membrane. It attaches peripherally to the crest of the spiral ligament, which in turn is an area of thickened, modified endosteum overlying the lateral wall of the cochlea. While the basilar m e m brane divides the lumen of the cochlea, it d o e s not extend all the way to the cupula but terminates just before it, leaving a small area of communication termed the helicotrenm between the scala vestibuli and the scala tympani. The membranous labyrinth is a system of delicate, epithelium-lined channels surrounded by connective tissue a n d lying within the osseous labyrinth (Fig. 1 - 9 ) . Like its osseous counterpart, the m e m b r a n o u s labyrinth has vestibular, semicircular, and cochlear c o m p o n e n t s that c o m m u n i c a t e with one another. The m e m b r a n o u s labyrinth exhibits certain general features: 1. Its luminal capacity is much less than that of the osseous labyrinth.

pO

Pertinent A n a t o m y

Pertinent A n a t o m y

''• 1. The m e m b r a n o u s labyrinth tends to be placed peripherally within the osseous labyrinth; it is surjounded by the perilymphatic space (and perilymph). In most locations this space is traversed by n u m e r o u s (Jelicate trabeculae extending from the endosteum to £e m e m b r a n o u s labyrinth. The exception to this is in the cochlea, where the trabeculae are very much (educed or absent.

is the most highly modified. Situated within the bony cochlea, where it lies upon the upper surface of the basilar m e m b r a n e , it is a triangular duct extending, the full length of the basilar membrane (but not to the apex of the cochlea). Basally it is continuous with the saccule through the ductus reuniens. The three basic structural c o m p o n e n t s of the cochlear due include the following:

3. The membranous labyrinth contains the recepj p t s for hearing and equilibration.

1. The vestibular membrane, which forms the roo, of the cochlear duct and separates the endolymphatic space of the duct from the perilymphatic space oi the scala vestibuli. It is an extremely thin m e m b r a n e (approximately 0 . 0 0 3 m m ) .

4. It is a self-contained system with no patent communication with other areas. 5 . The lymph.

membranous

labyrinth

contains

endo-

Individual Components of the Membranous Labyrinth

The vestibular portion of the m e m b r a n o u s labyrinth is characterized by two large dilatations, the Hfricfe and saccule. The utricle, located in the posterior portion of the osseous vestibule, receives the crura of the three membranous semicircular canals. F r o m its anterior end arises the minute utricular duct through which it communicates with both the endolymphatic duct and the saccule. Situated within the utricle on its floor and lower lateral wall is the macula, one of the receptor sites of the vestibular system. The saccule is located anteromedial to the utricle within the osseous vestibule. F r o m its posterior aspect arises the small saccular duct that is continuous with the utricular duct (hence, utriculosaccular) and the endolymphatic duct. Anteriorly the saccule is continuous with the cochlear duct through the extremely small ductus reuniens. The saccule has a macula located on its lateral wall. The endolymphatic duct arises from the union of the utricular and saccular ducts and passes through the vestibular aqueduct to terminate in a blind dilatation, the endolymphatic sac, within a dural cleft on the medial surface of the petrous portion of the temporal bone. Within the sac are extensive folds of epithelium with cores of vascular connective tissue, which would seem to indicate that this particular site is the region "'greatest physiologic activitv. The membranous semicircular canals conform closely to the configuration of their osseous counterparts. At the anterior ends of the anterior and lateral canals n d at the posterior (inferior) end of the posterior canal are prominent dilatations or ampullae, which house the receptor sites (cristae).

a

The cochlear portion of the m e m b r a n o u s labyrinth

2. The lateral wall, consisting of the sfrin vascularis, a highly vascular region situated on the inner surface of the spiral ligament. As its n a m e implies, it is characterized by its highly vascular nature and is generally believed to be the source of endolymph. 3. The floor, consisting of the organ of Corti, which is the sensory organ for hearing.

The Sensory Receptors of the Inner Ear

Within the vestibular portion of the inner ear the receptors consist of the following: 1. The cristae, located within the ampullae of thr m e m b r a n o u s semicircular canals. They consist oi thickened epithelium containing neuroepithelial hai; cells. Overlying the epithelium and extending to the opposite wall of the ampulla is the gelatinous cupula. The cilia of the hair cells project into the base of the cupula. 2. The maculae, which are located in the utricle and saccule and have similar structures. The hair cells of the neuroepithelium are stiff, nonmotile projections embedded in an overlying gelatinous m e m brane, the statoconic or otolithic membrane. This m e m brane is unique in that it contains n u m e r o u s crystals termed otoliths. The sensory portion of the cochlear duct, the organ of Corti or spiral organ, has the same basic structure as the cristae and maculae. It lies upon the basilar membrane and consists of supporting cells and hair colls overlaid by a gelatinous tectorial membrane. The supporting cells are of several different types; however, all contain fibrils within their cytoplasm, and their free edges form a reticular membrane against which the tectorial m e m b r a n e rests. The most important of the supporting cells are the phalangeal cells, arranged in a single inner row, and an outer group consisting of three to five rows depending on the

level of the cochlea under consideration, there being more rows apically than basally. The inner row is associated with a single row of hair cells, while the outer group has phalangeal cells alternating with rows of hair cells. Between the inner and outer group of phalangeal cells is an intercellular space extending the entire length of the spiral organ and termed the tunnel, inner tunnel, or canal of Corti. It is bounded by special supporting cells designated the inner and outer pillars (Corti's rods). Together the pillars and the canal form Corti's arch. Peripheral to the phalangeal cells are other supportive elements, the tall cells of Hensen and the shorter, more peripherally located cells of Claudius. The hair cells of the spiral organ have numerous "hairs" projecting from their reticular surface (40 to 100 per cell). The innermost of these cells are long and are thought to be the least sensitive to sound. In contrast, the outer hair cells are short, being wedged between the apical portions of the phalangeal cells.

Vascular Supply of the Inner Ear

The primary source of blood to the inner ear is the Inbi/riiiHiine (internal auditory) artery. While this vessel is usually described as originating from the basilar artery, it probably arises more frequently from the anterior inferior cerebellar artery. In addition, it may be duplicated by terminal branches that arise independently to enter the internal acoustic meatus. In its course the labyrinthine artery accompanies nerves VII and VIII through the internal acoustic meatus. Its main branches run in the endosteum of the labyrinth, and small branches traverse the trab e c u l e to gain the m e m b r a n o u s labyrinth. Apparently there are no functional anastomoses between these two areas of distribution. The most c o m m o n first branch of the labyrinthine artery is that which is distributed to the utricle, part of the saccule, and the anterior e n d s of the anterior and lateral semicircular canals. This branch has been called both the anterior vestibular and vestibular artery. When there is an apparent doubling of the labyrinthine artery, it is this branch that most frequently arises independently. The other two c o m m o n branches of the labyrinthine artery are the vestibulocochlear (posterior vestibular) artery, which is distributed to the saccule, the posterior semicircular canal and parts of the anterior and lateral canals, part of the utricle, and the entire basal coil of the cochlea; and the cochlear nrlcry, which is distributed to the remaining portion of the cochlea. There is consider-

21

able variation in the pattern of branching of the labyrinthine artery. Any one of the normal branches may be missing or may arise via a c o m m o n trunk with a n o t h e r branch. Descriptions of the venous drainage of the inner ear conflict. In all probability most are accurate, reflecting a considerable but normal variation. The described patterns include the following: 1. A vein of the vestibular aqueduct, draining most of the semicircular canals and emptying into either the sigmoid or the inferior petrosal dural sinus. 2. A vein of the cochlear aqueduct, draining the entire cochlea and vestibule. It runs in a long canal paralleling the cochlear aqueduct to enter the superior bulb of the internal jugular vein or the inferior petrosal dural sinus. 3. A labyrinthine vein, which seems to be inconsistent. W h e n present, it drains the apical and middle coils of the cochlea and traverses the internal acoustic meatus to become tributary to the inferior petrosal dural sinus.

Nerves of the Inner Ear Before describing the innervation of the inner ear we will consider the fundus of the internal acoustic meatus. The fundus is divided into superior and inferior portions by a horizontal bony ridge termed the transverse crest. Located posteriorly within the smaller superior depression are a number of small foramina that transmit the nerves to the utricle and the ampullae of the anterior and lateral semicircular canals. This is the superior vestibular area. Anteriorly within the u p p e r depression is a relatively large foramen that transmits the facial nerve. In the larger inferior depression, immediately u n d e r the posterior end of the transverse crest, is the inferior vestibular area, which contains small foramina transmitting the nerves to the saccule. Below and slightly posterior to the inferior vestibular area is the foramen singulare, through wiiich nerves pass to gain the ampulla of the posterior semicircular duct. Anteriorly the inferior depression is occupied by the foraminiferous spiral tract, a series of minute foramina arranged in spiral fashion that appose the base of the cochlea and the modiolus. At the center of the spiral is the somewhat larger orifice of the modiolar canal. The nerve of the inner ear is the vestibulocochlear (statoacoustic, acoustic, or auditory) nerve. Functionally, it consists of two divisions: 1. The vestibular division, containing fibers arising from the vestibular ganglion, a sensory ganglion situated at the lateral end of the internal acoustic meatus.

22

Pertinent A n a t o m y

These sensory fibers form the superior and inferior vestibular n e w s . T h e superior vestibular nerve supplies the ampullae of the anterior and lateral semicircular canals plus the maculae of the utricle and saccule. Hence, it is this nerve that enters the inner ear through the superior vestibular area of the fundus of the meatus. The inferior vestibular nerve supplies the ampulla of the posterior semicircular canal and the macula of the saccule. It is associated with the inferior vestibular area and the foramen singulare of the meatal fundus. 2. The cochlear division, consisting of fibers arising from the spiral ganglion, which is situated in the coils of the modiolus at the base of the osseous spiral

lamina. These fibers pass through the lamina to gain the organ of Corti. Within the internal meatus these fibers are associated with the foraminiferous spiral tract and orifice of the modiolar canal. Associated with the nerves of the inner e a r is the bundle of Oort, a small number of efferent fibers arising from the superior olive of the brainstem. These fibers run from the brainstem to the inner ear within the inferior vestibular nerve, then pass ovet to join the cochlear nerve. Although it is a s s u m e d that these fibers are distributed primarily to the cochlea, where they may play a part in some sort of feedback mechanism, their exact function has yet t•;• be determined.

CHAPTER 2 Pertinent Histology This short chapter presents four photomicrographs of horizontal temporal bone sections at different levels. The sole purpose is to provide a general orientation in terms of temporal bone anatomy; these sections are useful in achieving the three-dimensional visualization necessary for temporal bone surgery. A detailed description of horizontal temporal bone sections is beyond the purpose of this atlas. The horizontal sections are also to be used as references for

the pertinent! histopathologic slides described in this book, which* for practical reasons are included in their specific chapters rather than grouped together here. W h e n describing horizontal sections of temporal bones, "superior" m e a n s cephalad; "inferior" is caudad; "anterior" is ventral; "posterior" is dorsal; "lateral" is toward the external ear canal; and "medial" is away from' the external ear canal.

24

Pertinent 1 listology Pertinent Histology

25

FIGURE 2 - 2 FIGURE 2 - 1 This section is in the area of the epitvmpamim It is important to remember that the middle car cavitv extends superiorly above the tympanic m e m b r a n e It is at this level that the malleus can be laterally fixed (not shown in this section). The wide communication between the middle e a r a n d mastoid can be observed as can the close proximity of the incus and horizontal (lateral) semicircular canal to the aditus and antrum At this high level the tensor tympani occupies the anterior wall and is in close proximity to the facial nerve (FN), which is surrounded by a thin plate of bone that is sometimes dehiscent. It is also important

to recognize the thinness of the bone plate separating the vestibule from the internal auditory canal (pnrall'c' «r,vw>). I his must be kept in mind when doing ./abyrinthcctomy, since it is very easy to accidentally create a fistula with subsequent cerebrospinal fluir leak during this procedure. Note in these sectionthe air space that exists in the normal mastoid cavity c o m p a r e d with that in temporal bones with otitr media (see Chapter 1 0 ) . At this higher level, the nerves of the internal auditory canal are the facial nerve anteriorly and the superior division of the vestibular nerve posteriorly.

This section is at the level of the stapes footplate, which is bound to the oval window by the annular ligament. The short distance from the footplate to the contents of the vestibule (utricle and saccule) should be noted. There is very little room ( 1 . 5 to 2 . 0 m m ) to work with a Hough hoe (or similar instrument) when removing the footplate without touching vestibular structures. At this level the FN is located posterior to the oval window; dehiscence (sometimes bulging) is not u n c o m m o n at this site. This should be remembered when working in this area. This section also provides guidance for placing tubes in the superior quadrants of the tympanic m e m b r a n e . The risk of damaging the incus or leaving it directly exposed to the exterior by placing a tube

in the posterior superior quadrant is obvious in this section; the safe placement in the anterosuperior quadrant is more evident in Figure 2 - 3 . The tendon of the tensor tympani can be observed inserting^laterally over the anteromedial surface of the manubrium of the malleus. It is here that the tendon of the tensor tympani is sectioned (when this procedure is needed). The body of the incus is reduced in diameter at this level to form the body of the descending long crus (long process of the incus). The posterior incudal ligament can be observed as it attaches at the fossa of the incus (fossa incudis). At this level the nerves of the internal auditory canal are the cochlear nerve anteriorly and the inferior division jf the vestibular nerve posteriorly.

26

Pertinent Histology

Pertinent Histology

27

FIGURE 2-3 FIGURE 2-4 I n this section the e x t e r n a l e a r c a n a l a n d t y m p a n i c

ship

between

the

posterior

s e m i c i r c u h r canal

™H

At

this

lower

level

in

the

mesotympanum

the

p r o m o n t o r y is clearly apparent, as is the t y m p a n i c m e m b r a n e i n its full h o r i z o n t a l e x t e n t . T h i s s e c t i o n provides t h e thin p l a t e of b o n e t h a t s e p a r a t e s b o J s t r u c t u r e s An i m p o r t a n t f e a t u r e in this section is the relation-

m i c o ^ r X"^

Xet °

*

a

clear

image

of

the

middle

ear

space

a n t e r i o r l y a n d p o s t e r i o r l y for p l a c e m e n t of t u b e s in the

inferior

quadrants.

The

sinus

tympani

can

be

o b s e r v e d a n d t h e difficulty of c l e a n s i n g it a d e q u a t e l y if it is i n v o l v e d with c h r o n i c d i s e a s e c a n be s e e n . In these

four

figures

the

thinness of the

mucoperios-

t e u m s h o u W b e n o t e d a s a r e f e r e n c e for c o m p a r i s o n with the p a t h o l o g i c slides s h o w n in specific c h a p t e r s .

Pertinent Concepts in High Resolution Temporal B o n e Imaging

29

CHAPTER 3 Pertinent Concepts in High Resolution Temporal Bone Imaging FIGURE 3 - 1 . Normal temporal bone (1.5 mm thick axial LI images, w ?°oo;

Computed Tomography and Magnetic Resonance Imaging

High resolution computed t h e field

a

u

M

„„

o

r n

. | ) . The geniculate l l „ , head (lane curved arrow) and incus body

c a n a l ( i a £ )

,,|

m a

v e s i i b u

e ( o p e n a

m

w

P

studied with C T , but MR is the procedure of choice for e v a l u a t i o n o f i n t e r n a l a u d i t o r y canal m a s s l e s i o n s .

tomography (CT) and

magnetic resonance (MR) imaging have dramatically enhanced

, •

handle of malleus (curved arme); normal mastoid air cells Mule arrows).

Vascular Ultrasound for Atherosclerosis Screening

of temporal bone imaging. Thin

section axial a n d coronal C T p r o v i d e s detailed v i e w s of the ossicles, bony labyrinth, cochlea, and mastoid air cells (Figs. 3 - 1 t o 3 - 5 A ) . M R p r o v i d e s s u p e r i o r soft

tissue

contrast

resolution

over

CT

and

often

e l i m i n a t e s t h e n e e d for i n v a s i v e p r o c e d u r e s s u c h as arteriography 5B

to 3-9).

and

pneumocisternography

(Figs.

3-

T h e multiplanar characteristics of MR

p e r m i t d e m o n s t r a t i o n o f s o f t t i s s u e a n a t o m y i n anydesired plane of projection, and imaging parameters may

be

section tures

adjusted CT is

need

to

to

fit

each

recommended be viewed

in

particular

case.

whenever bony detail.

Thin struc-

Temporal bone

injuries, developmental anomalies, otosclerosis, and i n f l a m m a t o r y middle ear or mastoid lesions are best

High

resolution

r e a l - t i m e d u p l e x u l t r a s o u n d witrf.

D o p p l e r a n d spectral analysis is a

useful a n d cost-

e f f e c t i v e s c r e e n i n g p r o c e d u r e for cervical c a r o t i d atherosclerosis.

Real-time

ultrasound

provides

direct

visualization of the cervical carotid arteries (Figs. 3¬ 10, 3-11). D o p p l e r a n d s p e c t r a l a n a l y s i s d e f i n e f l o w patterns and

velocity.

These noninvasive screening

procedures are easily performed common complaints headedness,"

such as

upon patients with

"dizziness"

precluding the need

or "light-

for a r t e r i o g r a p h y

in most circumstances. MR shows immense promise for n o n i n v a s i v e s t u d y o f t h e i n t r a c r a n i a l v e s s e l s ( s e e Fig. 3 - 7 8 , C).

FIGURE 3-2. , , „ Mondini deformity in a child with congenital deafness. The deformed cochlea (arrow) is globular in configuration and is continuous with the deformed vestibule fourni rtrnite). Note an operative defect (ic/iilc imam) from previous exploratory surgery.

J

Pertinent C o n c e p t s in High Resolution

Tempora] B o n e Jmoging

Pertinent Concepts in High Resolution Temporal B o n e imaging

31

FIGURE 3 - 5 . Intraconalicular acoustic schwannoma shown with coronal CT (A) and MRt (R) A, There is marked expansion of the ny;ht internal auditory canal (arrow). 8, Expansile mass Cornue) is isointense with brain a. h

Pitfalls

tan he n u d e dow imhe

\ c i i l v the o p e n i n g o t the r o u n d win-

On occasion, it is nccess.irv or use.; I to

g e n t l v drill the . i n t e r i o r b o r d e r ol the n i c h e (I i ;. 51.

[ h o s e o f t h e facial r e c e s s a p p r o a c h itself.

2. Inadequate visualization of the round with

the electrode unable

to be passed

y(').

window,

beyond

the

hook.

I his will p r o v i d e a slightly larger o p e n i n g ". th

b e t e r v i s u a l i z a t i o n , a n d a t t h e s a m e t i m e will pr. a "straight s h o t " at the cochlea,

icnt

skipping the ' o o k

p o r t i o n that s o m e t i m e s is difficult to b y p a s s . P o s (ion the electrode in the o p e n i n g of the w i n d o w a n d

hen

g e n t l y p u s h it in, u s i n g a b l u n t pick or w i r e g u i c e or

Surgical Steps

o n e of the special e l e c t r o d e g u i d e s p r o v i d e d by implant manufacturers (Fig. 5 - 1 0 ) .

1. T h o s e

of

a

simple

mastoidectomy

and

recess approach.

facial

the

If there is s u n e

resistance, it is likelv that the electrode is c a u g h

up

in the h o o k . Retract the electrode gently and tr

to

r o t a t e it, w h i l e i m a g i n i n g t h e d i r e c t i o n o f t h e c o c h - e a .

2. P r e p a r e a s e a t for t h e i n t e r n a l r e c e i v e r .

O n t h e left, for e x a m p l e , t u r n g e n t l y t o w a r d t h e r ' ? h t

3. Insert the intracochlear electrode.

( c l o c k w i s e ) ; o n t h e r i g h t , t u r n g e n t l y t o w a r d t h e 'eft

7V.v( tvntiiiiicd on p a e e 59

FIGURE 5-8

55

56

Surgical I' rocedures

Surgical Procedures

Scala tympani

( '"

:'

"

A

A ~Iectrode In scala tympani

B 15mm

Facial nerve

o

'. . 1

P O R P s c a n b e s t a b i l i z e d b y m a k i n g a slit t h a t a l l o w s

s o l u t i o n s . G e l f i l m is an a p p a r e n t l y brittle film th t

a m o r e stable c o n t a c t with the stapes head. In spite

b e c o m e s soft a n d r u b b e r y w h e n m o i s t e n e d i n salin

of

of

It is u s e d to d i s c o u r a g e a d h e s i o n s , such as in s e p : •

Plastipore w o r k very well in properly selected cases

ration of the i n c u d o s t a p e d i a l joint from the t y m p a n . c

these

and

drawbacks,

remain

a

first

TORPs

choice

and

under

PORPs the

made

proper condi-

tions. Ceramics. produced at

.

m e m b r a n e . I n its d r y f o r m , G e l f o a m s h o u l d b e d t • c o m p r e s s e d ; w h e n saturated, it should be s q u e e z e i

Ceramics,

inorganic

high temperatures,

crystal are

the

materials "in"

mate-

rials i n o s s i c u l o p l a s t y a n d r e c o n s t r u c t i v e e a r s u r g e r y T h e y have been used successfully in orthopedics and

l o o k e d for ( F i g . 1 2 - 2 D , E ) . T h e t y m p a n i c m e m b r a n e itself m a y be n o r m a l , a t r o p h i c , sclerotic,

b e c o m e a focus of infection.

tracted, or adhesive.

Tissue

Adhesions

("Glues").

in o r d e r to r e m o v e air b u b b l e s . Gelfilm is not useft,! as a graft for t y m p a n i c m e m b r a n e p e r f o r a t i o n s . G e l f o a m s w e l l s as it a b s o r b s fluid. As it e x p a n d ? it i m p i n g e s on neighboring structures (which is whi

thick,

re-

the

T h e s e conoitions give an index of such factors as

Histoacryl (cy-

the u n d e r l y i n g c a u s e , e u s t a c h i a n tube function, aer-

Glues have been

d r e a m o f m a n y o t o l o g i s t s for y e a r s .

anobutyl acrylate) a n d Fibrin, the t w o t y p e s that are

ation, vascularity of the m e m b r a n e , and so on.

available,

of t h e s e will affect the graft take a n d influence the

ideal. must

work

fairly

acceptably

but

are

far

from

Either they m u s t await the test of time or we await

a

better

adhesive.

The

description

All

selection of the type of repair.

of

them is b e y o n d the s c o p e of this book.

Approach Myringoplasty-Type I Tympanoplasty

T h e r e are

no

fixed

rules

for a c h i e v i n g

t h e final

purpose, which is adequate visualization through an o p e n canal, allowing a g o o d a s s e s s m e n t and repair.

hydroxy-

biocompatible

efficient as a T O R P (total o s s i c u l a r r e p l a c e m e n t prosPlastipore (high-density polyethylene), which has

it w o r k s well in filling the middle ear cavity w h e n a n u n d e r l a y graft i s p l a c e d ) . G e l f o a m p o t e n t i a l l y m a y

the s a m e calcium-to-phcs-

natural

is

Bio-

material available. T h e essential aim in prosthetics is

T e f l o n is u s e d p r i m a r i l y as a p i s t o n for a

body

223

Tympanoplasty

A m y r i n g o p l a s t y a n d a t y p e I t y m p a n o p l a s t y in-

The approach

should

provide

a

clear

visualization

volve repair of the tympanic m e m b r a n e alone. " M y -

around the borders of the perforation and,

ringoplasty" is

clear visualization of the entire annulus. Otologists

the

term

used

when

the

operation

ideally,

d o e s not i n c l u d e raising flaps t o e n t e r t h e m i d d l e e a r

should be capable of adapting the approach

cavity,.whereas a tvpe I tympanoplasty implies the

n e e d s of the case a n d not vice versa. T h e r e are a

opposite.

Different' types' of

tympanoplasties

and

ossiculoplasties involve procedures in the different

number of

situations

structures of the middle ear at or b e y o n d (medial to)

lighted with

the

are relative.

tympanic membrane.

T h e broad

term

"tympa-

in

which

certain advantages over others.

n o p l a s t y " i s u s e d for a n y p r o c e d u r e w h o s e p u r p o s e

the

one

approach

T h e y will

understanding

to the

that

all

has

be highguidelines

T h e alternative a p p r o a c h e s are the transcanal, the

is to eradicate disease and reconstruct the hearing

endaural, and

mechanism

p r o a c h is u s e d in g e n e r a l for small p e r f o r a t i o n s , or

with

or

without

tympanic

membrane

the

postauricular.

A

for m e d i u m

previously described

that allows a clear visualization of the anterior border

under control,

an

overall

analysis of the required procedure involves several

of the perforation.

aspects.

'hat are

T h e anatomy of the tympanic m e m b r a n e must be

large

in

a

ap-

g r a f t i n g . P r o v i d e d t h a t all t h e i n t e r d e p e n d e n t f a c t o r s are

posterior perforations

transcanal

wide canal

I t i s i n a d e q u a t e for p e r f o r a t i o n s

or

that

involve

the

annulus,

or

for

c a s e s that m i g h t n e e d a n associated m a s t o i d proce-

considered. T h i s includes not only the site and extent

dure. An e n d a u r a l a p p r o a c h p r o v i d e s g o o d visibility,

of the perforation but also the status of the m e m b r a n e

especially

(atrophic, atelectatic, with tympanosclerotic plaques,

perforations, an associated canalplasty is necessary,

and so o n ) . Based on this information, an approach

This approach

i s s e l e c t e d , t y p e s o f s k i n flaps (if a n y ) a n d g r a f t i n g

small,

of

the

posterior quadrants.

allows a

thick meatus.

meatoplasty

provides good

visibility,

especially

the graft is d e c i d e d ( u n d e r l a y u n d e r t h e m e m b r a n e

margin of

tympanic

membrane:

or overlay o v e r the m e m b r a n e ) .

view without a canalplasty.

A

tympanic

membrane

perforation

may

be

re-

in

cases

of a

A postauricular a p p r o a c h also

material to be used are chosen, and positioning of

the

For anterior

of

the

it

anterior

allows

this

It is useful for m e d i u m

to large perforations as well as anteroinferior perfo-

stricted to o n e quadrant a l o n e — t h e posterosuperior,

rations,

posteroinferior, anterosuperior, or anteroinferior. A

Regardless of the approach,

with

or

without

alteration

of the

annulus.

preservation of the an-

perforation of Shrapnell's m e m b r a n e constitutes an

nulus maintains the middle ear space, provides sup-

e x c e p t i o n t o t h i s ; e x p l o r a t i o n i s a d v i s e d i n all c a s e s .

port, a n d r e d u c e s the risk of retraction.

B e c a u s e of the anatomic position of Shrapnell's m e m brane,

epithelial

ingrowth

is

always

a

possibility,

R e v i s i o n s u r g e r y i n g e n e r a l i s d o n e via a n a l t e r n a t e incision that a l l o w s a graft to be o b t a i n e d . T h e m a i n

e v e n w i t h a n o r m a l a u d i o g r a m (for e x a m p l e , a " c o n -

q u e s t i o n s in revisions are (1) W h y did the p r o c e d u r e

ductive" cholesteatoma).

fail

A p e r f o r a t i o n a l s o c a n in-

volve m o r e than o n e quadrant (Fig. 1 2 - 2 A , B), or it

initially?

(2)

Was

failure

caused

by

exposure,

clinical error, or u n d e r l y i n g d i s e a s e ?

m a y i n v o l v e the a n n u l u s . It can be total (Fig. 1 2 - 2 C ) ,

Whichever approach is chosen,

the canal should

central, or marginal. If there are several perforations,

be smooth and there should be no bony overhangs,

underlying disease (such as tuberculosis) should be

If

the

annulus

is

missing,

a

sulcus

(if

necessary)

224

Tympanoplasty 225

Tympanoplasty

should be created (to prevent blunting). If an attico-

a

tomy is performed,

perforation a n d toward the a n n u l u s (Fig.

the attic m u s t be reinforced.

If

flap,

an

incision

is

made

in

the

middle

of

the

1 2 - 5 / 1 , B)

the eustachian tube is dysfunctional a PE tube should

T h e t y m p a n i c m e m b r a n e is carefully reflected, allow-

be considered.

ing e n o u g h space to apply G e l f o a m in

Once formed

the and

approach the

has

tympanic

been

selected

membrane

and

per-

is visualized,

the next decision is the canal incisions to use. (Before elevating

the

flaps,

any

tympanic

membrane

work

the middle

ear a n d a m e d i a l ( u n d e r l a y ) graft (Fig. 1 2 - 5 C ) . T h e tympanic m e m b r a n e is repositioned and Gelfoam is applied over it (Fig. 1 2 - 5 D ) . F o r a s m a l l central p e r f o r a t i o n , an u n d e r l a y graft

[such as trimming the edges] should be performed,

is placed through the perforation (Fig.

12-5E), The

since it is simpler at this time a n d the m e m b r a n e is

edges of the perforation are trimmed

meticulously,

i n its n a t u r a l p o s i t i o n . ) T h e b a s i c p r i n c i p l e i s t o e n t e r

and

the

scraped

middle ear cavity (type

way and

that

allows

adequate

1

tympanoplasty)

inspection

efficient p l a c e m e n t of a graft.

of

the

in

a

cavity

T h e alternatives

the

undersurface

of

(freshened);

this

the

membrane

includes

is

gently

cleansing

(if

n e e d e d ) of the m a n u b r i u m . T h e middle ear cavity is filled with c o m p r e s s e d G e l f o a m (Fig.

12-5F) and a

are m a n y a n d vary according to n e e d a n d preference,

fascia graft is placed t h r o u g h the perforation, m a k i n g

as well as the imagination of the surgeon, A classic

sure that the e d g e s of the perforation are overlapped

p o s t e r i o r c a n a l flap (1 a n d 6 o ' c l o c k vertical i n c i s i o n s )

by the graft by m o r e t h a n 3 0 % . If n e e d e d , a piece of

offers a d e q u a t e e x p o s u r e in

m o s t (if n o t all) c a s e s

fascia i s p l a c e d b e t w e e n the t y m p a n i c m e m b r a n e a n d

a n d is a g o o d alternative. An anterior or an inferior

the long process of the malleus. T h e malleus handle

flap m i g h t suffice ( F i g .

can be de-epithelialized a n d a piece of fascia placed

12-3A-C),

or a

"swinging

d o o r " technique can be used (Fig. 1 2 - 3 D , E). If skin reinforcement

is

needed,

a

pedicled

flap

can

be

utilized. S o m e o f the m o s t c o m m o n l y u s e d flaps will

laterally. T h e s e procedures require a healthy, well-vascularized

tympanic membrane.

be described in the discussion of specific procedures. T h e y are simply alternatives and are not necessarily the only choices.

Overlay Technique in Central Perforation

Small Central Perforation Critical Points T h e edges of the perforation are

touched

with a

blunt pick m o i s t e n e d in trichloroacetic acid (Fig. 1 2 4/1). U p o n contact with the acid, the e d g e s acquire a white a p p e a r a n c e . A p a p e r patch (cigarette paper) is

1. C o m p ' e t e

de-epithelialization.

2. A well-defined,

well-placed anterior tympano-

meatal angle junction. 3 . A t t a c h m e n t o f graft t o h a n d l e o f m a l l e u s .

applied overlying the perforation (Fig. 1 2 - 4 6 ) . It is important

to

prevent a n y acid

from

falling into the

middle ear cavity since this is e x t r e m e l y painful; the

Procedure

i n s t r u m e n t s h o u l d be barely m o i s t e n e d . If this c o m plication

occurs,

neutral

pH

otic

drops

should

be

temporal

i c a t i o n . T h i s d o e s n o t w o r k all t h e t i m e a n d c a n o n l y

posterior c a n a l is m a d e at t h e j u n c t i o n of the lateral

be u s e d

and m i d d l e thirds of the canal.

for a

small

perforation

in

a

healthy mem-

For

T h i s p r o c e d u r e in-

tiny

central

perforations,

the

edges

can

be

d o w n to 2 mm lateral to the a n n u l u s (excepting the

trimmed (Fig. 1 2 - 4 C , D); a small triangle w e d g e with

area of skin c o n t a i n i n g the vascular strip).

its b a s e i n t h e a n n u l u s i s t h e n c r e a t e d ( F i g . 1 2 - 4 E ) .

incisions are m a d e at 10 a n d 1 o'clock (Fig. 1 2 - 6 / 1 ) .

The annulus is elevated (anteroposterior edge) and

T w o circumferential incisions are m a d e ,

slid t o w a r d t h e p r o x i m a l ( n o n e l e v a t e d ) e d g e , a l l o w -

mm

ing

tween 10 and 1 o'clock) and the second at the junction

the edges of the

together (Fig. FIGURI; 12-2

fascial graft o b t a i n e d . T h e incision of the

volves r e m o v a l of the canal skin from this junction

brane.

E

A postauricular approach has been selected and a

used in conjunction with an anti-inflammatory med-

12-4F).

tympanic membrane Small

to come

pieces of Gelfoam

are

applied over the approximated e d g e s F o r a very small central perforation that requires grafting, the e d g e s are t r i m m e d a n d the undersurface of the m e m b r a n e is gently scraped. Instead of raising

lateral

to

the a n n u l u s

(excepting

Vertical

t h e first 2

the

area

be-

of the lateral and middle thirds of the canal. (This is an extension of the canal

incision along the whole

circumference.) T h e skin is carefully elevated in one piece a n d preserved. A canalplasty is d o n e if n e e d e d . The tympanic m e m b r a n e is meticulously de-epitheText

continued

on

page

230

226

Tympanoplasty

Tympanoplasty

1

(~

....""

.....

----------------.,

\

E

fiCURE 12-4 rieUR!' 12-3

227

228

Tympanoplasty

Tympanoplasty

229

Tympanoplasty 230

Tympanoplasty

lialized curets

with

a

(Fig.

joint or

12-68).

No.

The

2 canal

knife or s m a l l

middle ear is

filled

vertical i n c i s i o n s at 1 a n d 6 o ' c l o c k is u s e d ( F i g . 1 >-

with

7 A); t h i s i s a g o o d c h o i c e b u t n o t t h e o n l y o n e . T u e

c o m p r e s s e d G e l f o a m , a n d t h e g r a f t i s n o t c h e d t o fit

flap is raised, a n d

around

beneath

the

manubrium

(Fig.

12-6C).

(The

manu-

the

the m i d d l e ear cavity is enter, d

annulus

Remember

that

the

annul, s

b r i u m is d e - e p i t h e l i a l i z e d a n d c l e a n s e d . ) T h e graft is

p r o v i d e s s u p p o r t a n d a l l o w s for m a i n t e n a n c e of ti e

placed e m b r a c i n g the m a n u b r i u m ; if n e e d e d , a piece

middle ear space. T h e middle ear space is inspecte i.

o f fascia i s p l a c e d o v e r the m a l l e u s h a n d l e (Fig. 1 2 -

(For inspection and evaluation,

6 D ) . T h e s k i n graft i s t h e n r e t u r n e d , o v e r l a p p i n g the

for A t e l e c t a t i c T y m p a n i c M e m b r a n e i n C h a p t e r I f . )

fascia

F o r this p r o c e d u r e (repair of a perforation a n d rein-

for a

few

millimeters.

Special care

must be

o b s e r v e d anteriorly in order to a v o i d b l u n t m g of the

f o r c e m e n t of

graft in the anterior t y m p a n o m e a t a l a n g l e . T h e canal

normal.

is packed,

usually with G e l f o a m in the medial two

the

membrane)

see Tympanoplas y

it

is

assumed

to

t e

A p i e c e o f t h i n S i l a s t i c s h e e t i n g i s p l a c e d f r o m tl"2

thirds (Fig. 1 2 - 6 F ) . In c a s e s w h e r e there is no fibrous

sinus

a n n u l u s , the sulcus should be c h e c k e d ; if shallow, it

m i d d l e e a r c a v i t y is filled w i t h c o m p r e s s e d G e l f o a n ,

can be drilled with a small bur.

a n d a piece of Gelfilm is placed over the i n c u d o s t i -

Incisions are closed

with appropriate sutures a n d a d r e s s i n g is applied.

tympanic

pedial joint

area

(not

to

under

the

the

eustachian

annulus),

tube.

Ths

between

th t

joint and the m e m b r a n e , in order to avoid adhesions from t h e graft t o t h e j o i n t ( F i g . 1 2 - 7 8 ) .

P r o b l e m s and C o m p l i c a t i o n s

The

Blunting of the anterior tympanomeatal the

most

feared

complication,

and

angle is

usually

occurs

w h e n there is no a n n u l u s and no sulcus. Drilling of the sulcus is helpful. Tight packing at this angle is i m p o r t a n t ( r o s e b u d p a c k i n g with O w e n ' s silk w o r k s quite graft

well

for

(lateral

this

purpose).

displacement)

Lateralization

happens

less

of

the

frequently

if the tip of t h e m a l l e u s h a n d l e is p l a c e d o v e r the fascia.

Residual cholesteatoma occurs w h e n dc-epi-

thelialization

of the

tympanic membrane

is incom-

fascia

greater than

graft the

is

positioned

extent

of the

over an

area 3 0 ?

perforation,

since

i:

will retract b y a b o u t 3 0 % ( F i g . 1 2 - 7 C ) . O n e c o n c e r t : with

grafts

is

the

possibility

of

lack

of

adequati

contact with the overlying tympanic m e m b r a n e .

B)

this "falling into the m i d d l e e a r c a v i t y " the bridging function

might

be

lost.

Although

compressed

Gel-

foam p r o v i d e s a d e q u a t e c o n t a c t (if placed c o r r e c t l y ) , a s o u n d alternative (with proven g o o d results) is the use

of

microclips

to

overlying membrane.

secure

the

graft

against

the

If the tympanic m e m b r a n e is

plete. Reperforation anteriorly is especially c o m m o n

w e l l d e - e p i t h e l i a l i z e d t h e c l i p s will not c a u s e a p r o b -

if there is no a n n u l u s . This is involved with support

lem;

o f t h e graft ( b y t h e a n n u l u s ) a n d v a s c u l a r i z a t i o n i n

nique is not d e s c r i b e d in this atlas.) It is useful to

eventually

thev

will

be

extruded.

(This

tech-

l e a v e a tail ( o f t h e f a s c i a ) t o w a r d t h e p o s t e r i o r b o n •

the area

canal

to

be

removed.

c o n s e r v a t i v e l y ( i f a t all having

Underlay Graft for Posterior Perforation in Atrophic Membrane

the

graft

This

should

possible)

rest o v e r the

be

done

verv

in o r d e r to a v o i d

incudostapedial joint

( w h i c h by n o w is c o v e r e d with G e l f i l m ) . T h e graft is placed e m b r a c i n g the handle of the malleus. A small p i e c e of fascia can

then be placed

over the handle.

T h e p i e c e o f s k i n h a r v e s t e d via t h e L e m p e r t I I i n c i Using

an

endaural

approach,

a

temporal

fascia

graft (by L e m p e r t I i n c i s i o n ) a n d a s m a l l s k i n graft (by a L e m p e r t II incision) h a v e b e e n obtained. T h e tympanic

membrane

is

visualized;

if

necessary,

a

sion is placed over the fascia ( c o v e r i n g the perforation) (Fig. Endaural

12-7D). incisions

T h e ear is packed are

closed

with

(Fig.

the

12-7E).

appropriate

sutures, a n d a d r e s s i n g is a p p l i e d .

canalplasty is d o n e . T h e e d g e s of the perforation are trimmed, the undersurface of the m e m b r a n e is gently scraped,

and

the

membrane

is

de-epithelialized.

C o m p l e t e de-epithelialization m u s t be d o n e if a skin graft

is

to

• however,

be

used.

complete

If the

membrane

de-epithelialization

Underlay Graft for Large Anterior Perforation

is atrophic, might

be

m o r e h a r m f u l t h a n useful (an u n d e r l a y graft i s b e i n g u s e d ) b e c a u s e o f t h e p o t e n t i a l for t e a r s . If a PE t u b e is being c o n s i d e r e d , this is the time t o s e l e c t a n a r e a a n d p l a c e it. In this e x a m p l e , a c l a s s i c p o s t e r i o r c a n a l flap w i t h

A t e m p o r a l f a s c i a g r a f t h a s b e e n o b t a i n e d v i a th< postauricular approach. A posterior canal incision v made at

the b o n y cartilaginous junction.

The

tym

p a n i c m e m b r a n e i s v i s u a l i z e d , t h e e d g e s o f t h e perforation

are

trimmed,

the undersurface

is

scraped,

FIGURE 1 2 - 7 .

231

233

Tympanoplasty

a n d t h e m e m b r a n e i s d e - e p i t h e l i a l i z e d . (It i s a s s u m e d

it

that a c a n a l p l a s t y is n o t n e e d e d . )

ossicles,

I n c i s i o n s are m a d e for t h e flap ( a c l a s s i c p o s t e r i o r canal tympanoplasty incision, although others could

the

use

of

the

tympanic

membrane

or

or a t y m p a n i c m e m b r a n e with ossicles.

A

d o n o r m e m b r a n e m u s t be selected of the p r o p e r size a n d s i d e t o fit w e l l i n t h e r e c i p i e n t .

have b e e n m a d e a s well) (Fig. 1 2 - 8 4 ) . T h e " s w i n g i n g doors"

allows

Assuming

either

an

endaural

or

a

postauricular

i m p l y t h e e l e v a t i o n o f s u p e r i o r l y a n d inferi-

approach, e n o u g h b o n e is r e m o v e d (by canalplasty)

orly b a s e d skin flaps. T h e horizontal incision is m a d e

to c o m p l e t e l y visualize the a n n u l u s (or the sulcus, if

5 to 7 mm lateral to t h e a n n u l u s . T h e flap is d i v i d e d

the a n n u l u s is not present).

w i t h a v e r t i c a l i n c i s i o n a t 9 o ' c l o c k (it c o u l d a l s o b e

meticulously cleansed, and the tympanic membrane

at 11 o'clock); this incision involves both the tympanic

remnants

m e m b r a n e a n d the a n n u l u s . T h i s results in two flaps

absent, the sulcus is carefully drilled in o r d e r to seal

(one superiorly a n d o n e inferiorly b a s e d ) , w h i c h are

the allograft in g o o d position.

elevated anteriorly up to (and b e y o n d

if necessary)

the m a l l e u s superiorly, a n d to 6 o'clock (or further) inferiorly.

(It i s a s s u m e d t h a t all t h a t i s n e e d e d i s p l a c e m e n t o f a graft.)

Incisions are

m a d e at

include the annulus,

11,

If

2,

the

and

annulus

is

7 o'clock and

unless the a n n u l u s is complete

S o m e G e l f o a m is placed, a n d allograft is positioned first o v e r t h e m a l l e u s ( F i g . 1 2 - 9 B ) . T h e f l a p s a r e t h e n repositioned.

I f o n l y t h e a n n u l u s i s left a n t e r i o r l y , t h e p r o b l e m support

becomes

an

issue.

foam p a c k i n g should be planned.

Abundant

incisions

3

to 4

mm

in

length

(or

longer

if

Packing

is

done,

the

incisions

are

closed (Fig. 1 2 - 9 C ) , and a dressing is applied

Gel-

A good choice is

to de-epithelialize the a n n u l u s anteriorly and to make small

de-epithelialized.

(Fig. 1 2 - 9 4 ) . T h e flaps e x p o s e the m i d d l e e a r cavity.

T h e middle ear cavity is entered and examined

of.graft

are

T h e malleus handle is

A n a l l o g e n e i c t y m p a n i c m e m b r a n e graft tain

drawbacks.

Different

sides

(right

has cer-

or

left)

sizes m u s t be available in the operating room. not

easy

to

position

the

graft

properly.

and It is

Allografts

n e e d e d ) a n d raise a s m a l l anterior flap. T h e a n n u l u s

tend

i s g e n t l y e l e v a t e d a n t e r i o r l y for t h e s a m e e x t e n t a s

granulation tissue in the middle ear cavity.

the incision ( m a d e in the skin of the canal), a n d the

should be used, as well as G e l f o a m [conservatively]).

fascia

Immunologic

graft is

anterior

canal

flap (Fig. graft

in

pulled and

12-8B,

with

the

small

anterior

C). T h i s avoids retraction of the

critical

rejection

and

are

sometimes

associated

occurs.

a

potential

for t r a n s m i t t i n g viral

positioning is similar to that in the e n d a u r a l a p p r o a c h

easily

eliminated

s o u r c e of the allograft o b v i o u s l y is critical

tympani

to

the

(This

particles from

d e s c r i b e d a b o v e . ) A p i e c e of thin Silastic s h e e t i n g is sinus

with

(Silastic is

fairly w e l l c o n t r o l l e d , h o w e v e r . ) I n a d d i t i o n , t h e r e i s to

the

area.

adhesions

donor

from

a

covered

the

form

( T h e rest of t h e graft

placed

such

beneath the annulus onto

to

the

recipient, by

the

since s o m e viruses are not sterilization

processes.

The

eustachian

t u b e . T h e c a v i t y i s filled w i t h c o m p r e s s e d G e l f o a m ; a piece of Gelfilm is placed over the incudostapedial joint. T h e graft is p l a c e d p o st er i o r l y as well, a n d the

Tympanoplasty-Ossiculoplasty

flaps are r e p o s i t i o n e d (Fig. 1 2 - 8 D ) . ( N o t e the distinct advantage of leaving

the vascular strip u n t o u c h e d . )

Packing is d o n e . Incisions are closed with appropriate s u t u r e s , a n d a d r e s s i n g is applied.

The

title

of

this

section

is

chosen

for

didactic

p u r p o s e s . H o w e v e r , the r e a d e r s h o u l d b e a w a r e that an o s s i c u l o p l a s t y is part of a t y m p a n o p l a s t y . T h e s e procedures involve

restoring

the sound

conduction

capabilities of the ossicular chain with or without a t y m p a n i c m e m b r a n e graft. T h e e n d result s h o u l d b e

Allograft for Total Perforation

continuity in vibration of the n e w c h a i n , with a solid contact with

l

he

tympanic membrane and a

mobile

oval w i n d o w m e m b r a n e o r plate. The allograft

use

of

an

constitutes

allogeneic one

more

tympanic

restoring continuity of the m e m b r a n e .

The

ossicular

chain

or

its

components

can

be

affected by fixation, dislocation, fracture, or dissolu-

Its i n d i c a t i o n s

tion (resorpti j n ) . T h e s e c o n d i t i o n s m a y b e c o n g e n i -

means

are s i m i l a r to o t h e r s , but this graft is e s p e c i a l l y u s e d

tal, o r t h e y c a n b e c a u s e d b y t r a u m a ,

for f a i l u r e s o f s t a n d a r d

re-

i n f e c t i o n . Th-.> c h o i c e o f p r o c e d u r e w i l l d e p e n d u p o n

tympanoplasty

(such

as

neoplasm, or

and

the type of ossicular p r o b l e m , the a n a t o m i c environ-

in c a s e s in w h i c h t h e r e is a high risk of failure with

m e n t , the s p a c e available (intact post wall, canal wall

standard tympanoplasty.

down,

and

(which

in

current

rïCURE 12

membrane of

effective

perforations or lateralization

of grafts),

An allograft is not a pana-

cea and is not easy to position adequately; however,

so turn

on),

and

depends

the

status

upon

the

of

the

status

mucosa of

the

234

Tympanoplasty

•

underlying

disease).

For

practical

purposes,

it

is

a s s u m e d that the u n d e r l y i n g disease is u n d e r control and that the middle ear space is adequate. sible

ossicular

changes

and

examples

b o d y for fitting u n d e r t h e m a l l e u s h a n d l e (Fig.

12-

114, B).

All p o s -

of

235

Tympanoplasty

3. U s i n g

cortical

bone.

A

graft

that

is

shaped

surgical

similar to a sculptured incus or malleus head can be

repair in s e l e c t e d s i t u a t i o n s will be d i s c u s s e d , w i t h

d r i l l e d , c r e a t i n g a c o n c a v e h o l e t o fit o v e r t h e h e a d

the u n d e r s t a n d i n g that there are o t h e r choices avail-

of the stapes a n d a n o t c h or a g r o o v e to fit u n d e r

able.

t h e m a l l e u s h a n d l e ( F i g . 1 2 - 1 1 C , D ) . (If d e s i r e d , a T shaped cortical b o n e can be used.) 4. U s i n g a partial ossicular r e p l a c e m e n t prosthesis

Isolated Ossicular Lesions

( P O R P ) . T h e larger surface area of a P O R P provides more stability; h o w e v e r ,

it m u s t be covered with a

thin piece of cartilage ( s u c h as tragal cartilage) that

Malleus

exceeds

(Fig. 1 2 - 1 0 4 )

must

T h i s is an essential b o n e in ossiculoplasty repair. T h e presence or a b s e n c e of the handle of the malleus, together with

the presence or absence of an

and mobile stapes,

intact

will d e t e r m i n e in great part the

type of procedure to be performed. T h e m a l l e u s is rarely affected alone; if it is, the may

also

associated

be

with

a a

traumatic mobile

dislocation.)

stapes,

an

If

it

is

atticotomy

is

d o n e with e x p o s u r e of the incudomalleal joint (Fig 1 2 - 1 0 B , C) (see C h a p t e r 13). T h e fixation is verified, and the joint is separated with a joint knife. Points to remember:

slight

PORP.

tension

When

over

placed,

the

it

tympanic

the

PORP

and

the

malleus

handle.

If there is no

malleus handle, the cartilage is placed directly under the

tympanic

graft;

in

membrane

these

cases,

a

or

tympanic

large

piece

membrane

of cartilage

is

S o m e s u r g e o n s even suture the cartilage

to the h e a d of the P O R P . In the distal portion of the P O R P , a n o p e n i n g o r n o t c h i s m a d e for b e t t e r c o n t a c t with the h e a d of the stapes and stapedial tendon. In s o m e c a s e s a P O R P can be carved from cartilage, and t h i s t y p e o f g r a f t fits q u i t e w e l l ( F i g . 1 2 - 1 2 B ) . I t a l s o allows trimming of the head of the cartilage P O R P t o fit t h e a n g l e d p o s i t i o n o f t h e m e m b r a n e ( F i g .

12-

the incudosta-

12C). In positioning P O R P s (and T O R P s ) , abundant

pedial joint b e f o r e drilling in the attic. T h i s will h e l p

Gelfoam is placed in the middle ear cavity in order

to avoid inner ear d a m a g e . Reinforcing the postero-

to

superior canal quadrant (atticotomy site) before clo-

positioning the

sure

ramic P O R P s are also available (Fig. 1 2 - 1 2 D ) .

will

discourage

Disarticulate

a

m e m b r a n e (Fig. 1 2 - 1 2 4 ) . T h e cartilage is b e t w e e n

preferred.

p r o b l e m usually is an anterior fixation of the h e a d . (It

the edges of the

provide

retraction

pockets

and

other

provide

support

and

maintain

flaps a n d

position

after re-

tympanic membrane.

Ce-

complications. The

head

of

the

malleus

is

amputated

with

a

m a l l e u s n i p p e r (Fig. 1 2 - 1 0 D ) . T h e i n c u s a l s o i s re-

Incus

(Fig. 1 2 - 1 3 4 )

m o v e d , s i n c e it h a s lost its a r t i c u l a t i o n to the h e a d o f t h e m a l l e u s . R e c o n s t r u c t i o n will b e b a s e d t o w a r d the head of the stapes. laying

the

tympanic

There are two alternatives:

membrane

(intact

or

grafted)

The assume

incus an

problems

intact

and

malleus

repairs handle

discussed

and

here

stapes.

The

incus is the ossicle most c o m m o n l y affected by ear

o v e r t h e h e a d o f t h e s t a p e s ( c l a s s i c t y p e III t y m p a -

infections

n o p l a s t y ) (Fig. 1 2 - 1 0 E ) , a n d placing a graft or pros-

trauma (fracture-dislocation).

(erosion

of

the

lenticular

process)

and

It may also be absent

thesis b e t w e e n the mobile handle of the malleus (the

( o w i n g to t r a u m a or p r e v i o u s s u r g e r y ) or fixed (usu-

fixed h e a d has b e e n a m p u t a t e d ) a n d the h e a d of the

ally i n a s s o c i a t i o n w i t h t h e m a l l e u s h e a d ) .

stapes.

The

establishing

latter course continuity

is

in

better

an

in

adequate

terms

of

middle

reear

space. This can be d o n e in a n u m b e r of ways: 1. Using

the

head

of

the

malleus.

Holding

If e r o s i o n involves a

small

p o r t i o n of the distal

e n d o f t h e l e n t i c u l a r p r o c e s s , c o n t i n u i t y c a n b e reestablished by any of the following methods:

the

1. U s i n g a cortical b o n e c h i p . A s q u a r e of b o n e is

head of the malleus with an ossicle holder, shape it

delineated

t o fit b e t w e e n t h e h e a d o f t h e s t a p e s a n d h a n d l e o f

s m a l l a c e t a b u l u m i s drilled for t h e h e a d o f t h e s t a p e s ,

the m a l l e u s . Drill a h o l e in it to r e c e i v e the h e a d of

a n d a g r o o v e for t h e r e m a i n i n g l o n g p r o c e s s o f t h e

t h e s t a p e s . T h e n flatten it ( n o t c h it a little, m a k i n g a

incus (Fig. 1 2 - 1 3 B - E ) .

g r o o v e ) t o fit u n d e r t h e h a n d l e ( F i g . 1 2 - 1 0 F ) .

2. U s i n g

2. U s i n g the incus. T h e short p r o c e s s of the incus

FIGURE 12-9. is

clipped.

An

acetabulum

is

drilled

in

the

long

shaped

in

a

the cortex,

cartilage

similarly

to

the

removed,

chip.

A

cortical

and shaped.

piece bone

of chip

A

cartilage can

be

used.

p r o c e s s for fitting o v e r t h e h e a d o f t h e s t a p e s . T h i s

3. U s i n ^ a p r o s t h e s i s that e m b r a c e s b o t h t h e re-

is followed by drilling a g r o o v e o v e r the remaining

maining le iticular process and the head of the stapes. Text

continued

on

page

241

236

Tympanoplasty

Tympanoplasty

lncudoma/leal

JOint

II

A

B

c D

Graft

E

FIGURE 12-10.

Type III

FIGURE 12-11

237

Tympanoplasty

FIGURE 12-13.

241

Tympanoplasty

[f there is dislocation, the ideal p r o c e d u r e is reapproximation

and

repositioning

using

Gelfoam

or

rosis. H o w e v e r , it is e s s e n t i a l to do this s t a p e d e c t o m y in a " d r y e a r " a n d as a s i n g l e p r o c e d u r e .

It s h o u l d

" g l u e " (Fibrin or H i s t o a c r y l ) , or both. H o w e v e r , this

not

tympano-

is s e l d o m possible.

plasty b e c a u s e of a high risk of s e n s o r y hearing loss.

In traumatic dislocations, adhe-

sions a n d fixations are very c o m m o n .

be

performed

in

conjunction

If a t y m p a n o p l a s t y is p e r f o r m e d ,

If r e a p p r o x i m a t i o n is not possible, or interposing

a

the stapedectomy

is delayed. Careful staging is crucial.

b o n e o r c a r t i l a g e i n l e n t i c u l a r e r o s i o n d o e s n o t suffice, t h e r e are a l t e r n a t i v e s :

with

Fractures of

the crura

are

treated

with

a

piston

prosthesis from the incus to the oval w i n d o w , unless

1. I n c u s t r a n s p o s i t i o n . A small a t t i c o t o m y is d o n e ,

the fracture is the rare o n e that allows a c r u r o t o m y .

and the incus is carefully separated from the malleus.

Again, t h e s e p r o c e d u r e s are d o n e in a "dry ear." In

It is

cases of fractured crura a n d footplate,

s h a p e d by

removing the

long process,

and

a

it is safer to

n o t c h for t h e s t a p e s h e a d i s m a d e a t t h e e n d o f the

remove

short process. T h e articulating surface is enlarged to

seal the w i n d o w . (A wire c o n n e c t i v e tissue prosthesis

accept the m a l l e u s h a n d l e (Fig. 1 2 - 1 4 / 1 ) .

is preferred but it is not essential.) An alternative in

2. Use

of

the

malleus

head.

Once

the

head

is

r e m o v e d , t h e s i t u a t i o n is as d e s c r i b e d for fixation of

the

footplate a n d

use

connective

tissue

to

fractured crura a n d intact mobile footplate is the use of an inverted allograft s t a p e s (Fig. 1 2 - 1 4 C ) .

the h e a d of the m a l l e u s . T h e s a m e p r o c e d u r e s apply, except

that

if

the

malleus

is

mobile and

the head

Combined Ossicular Problems

itself is not used (and any of the o t h e r alternatives are not preferred),

t h e m a l l e u s h e a d i s left i n p l a c e Repairs b e c o m e more troublesome if the malleus

and only the incus is removed. In

the case of a missing incus,

native

remains

valid.

In

all

of

the s e c o n d alterthese

procedures,

allogeneic (allograft) ossicles and cartilage are also a good

alternative is

to

use

an

thesis m a d e of hydroxyapatite. The

the

malleus

large end

of the

and

interposition

A pocket is created

the overlying

prosthesis

n e w l y created p o c k e t (Fig. that

stability

tympanic

is

membrane.

placed

over

the

is

12-14B). The advantage

provided

membrane

and

by

utilizing

malleus

both

handle,

the

with

no

c o n n e c t i o n t o t h e b o n y a n n u l u s o r facial ridge. T h i s i s a c l e v e r p r o s t h e s i s ( w h i c h still m u s t s t a n d t h e test of time, however).

It must be mentioned, however,

that

is

drilling

in

it

not

so

simple

as

suggested

Patience, carefulness, and copious irrigation are recommended. material

(the

An

This means

w h i c h carries a h i g h e r risk of

failure, or a l o n g e r p r o s t h e s i s m u s t be u s e d from the

additional

Wehrs

incus

prosthesis prosthesis)

of

this

fulfills

same very

Fixation of the head of the malleus associated with a

fixed

paired

stapes with a

has

the

drawbacks

the

drilling

and

been

shown

to be

re-

lateralization

and

loss

It must be r e m e m b e r e d

of that

of the oval w i n d o w is a potential c o m p l i c a t i o n . Reg a r d l e s s of t h e graft or p r o s t h e s i s , an a d e q u a t e seal is essential. Alternatives include the use of a T O R P , a TORP-shaped ceramic

cortical

prosthesis,

or a

bone

ossicle,

sculptured

cartilage,

or

ossicle (autolo-

gous or allogeneic). In c a s e s of fixation of the ossicular c h a i n by tymcompletion

without

has

w h e n e v e r t h e s t a p e s f o o t p l a t e is r e m o v e d , a fistula

malleus

head

of

adequate conductivity.

panosclerosis,

stapes

footplate

malleus-to-oval-window wire connec-

tive t i s s u e p r o s t h e s i s . W h i l e this is a g o o d a l t e r n a t i v e , it

nicely the function of a sculptured incus b e t w e e n the and

(or b o t h ) are a b s e n t .

tympanic membrane,

pros-

h e a d of the s t a p e s a n d the distal (thin) e n d in this is

or stapes

that the p r o s t h e s i s m u s t b e s u p p o r t e d b y t h e grafted

tympanic m e m b r a n e to the oval w i n d o w .

Another method between

handle

of

the the

first

stage

malleus,

implies

mobilization,

disarticulation

of

the

sculpturing of the incus. This too m u s t be evaluated

i n c u s , a n d S J o n . T h i s p r e p a r e s for a s e c o n d p r o c e -

over time.

dure

in

which

the

stapedectomy

is

done.

Surgical

repair involves the alternatives described below. When

both

the

malleus

and

incus

are

absent

(usually s e e n in c h r o n i c otitis m e d i a c a s e s , a n d not

Stapes

uncommonly

in

tympanomastoidectomy

proce-

dures), or w h e n both ossicles are a single, congenital, Fixation of the stapes by otosclerosis is dealt with in C h a p t e r 13.

F i x a t i o n r e l a t e d t o i n f l a m m a t i o n (fi-

nonfunctional t y p e III

" m a s s , " the alternatives are a classic

t y m p a n o p l a s t y or use of a short

prosthesis

brosis) or t y m p a n o s c l e r o s i s is rare in an isolated form

or graft ( d e s c r i b e d a b o v e ) , if the s t a p e s is intact a n d

(that is, n o t affecting o t h e r o s s i c l e s a t t h e s a m e t i m e ) .

mobile.

In t h e s e e x c e p t i o n a l c a s e s , a s t a p e d e c t o m y will suf-

prosthesis ( t y m p a n i c m e m b r a n e to footplate or oval

fice a n d t h e r e s u l t s s h o u l d b e a s g o o d a s i n o t o s c l e -

w i n d o w graft) is n e c e s s a r y

If

the

stapes

is

fixed

or d a m a g e d ,

a

long

243

Tympanoplasty

If the malleus is absent and there is an intact a n d

15C).

A c e r a m i c T O R P can also be u s e d (Fig.

12-

However,

15D), as well as a sculptured incus. T h e latter should

a l o n g p r o s t h e s i s is indicated if the s t a p e s is d a m a g e d

be flattened toward the t y m p a n i c m e m b r a n e in order

(Fig.

to provide a s m o o t h and w i d e contact. If the malleus

mobile stapes, a short prosthesis is used. 12-14E).

In

cases of tympanomastoidectomy,

the concept

handle

is

present,

drilling

a

groove

in

the

TORP

of space b e c o m e s relevant in terms of reconstruction

provides better stability. W h e n e v e r a long prosthesis

At this point a n d with this type of disease, an intact-

( T O R P type) is placed o v e r an oval w i n d o w without

b r i d g e t y m p a n o m a s t o i d e c t o m y m a k e s g o o d s e n s e (if

a f o o t p l a t e , t h e r e is a p o s s i b i l i t y of a fistula a n d g o o d

n e e d e d , of course; if possible, an intact-wall proce-

seal is n e e d e d .

dure is preferred).

(for

As m e n t i o n e d earlier, a critical factor is t h e p r e s ence or absence of the malleus handle.

An equally

example,

If t h e r e is a p o t e n t i a l for retraction eustachian

prostheses may the oval

tube

dysfunction),

lead to fistulization

by

these

sliding into

window.

important factor ( s o m e t i m e s o v e r l o o k e d ) is the prese n c e or a b s e n c e of a mobile footplate. For practical purposes,

the

use

of

a

TORP

will

be

described,

Pertinent Histopathology

followed by other alternatives.

Placement of a

FIGURES 12-16 TO 12-18

TORP

C h r o n i c otitis media with perforation of the tymT w o points of c o n t a c t are crucial. T h e usual ten-

panic m e m b r a n e . T h e lower magnification (Fig. 1 2 -

dehcy.is.to think in terms of extrusion a n d forget the

16)

distal

brane; (1) the o u t e r e p i t h e l i u m (stratified s q u a m o u s

end

window

of the T O R P (over the

footplate or oval

graft).

shows

the

three

layers

of the

tympanic

mem-

epithelium), c o n t i n u o u s with that of the external ear

T h e T O R P is cut to the n e c e s s a r y length. T h i s m a y

canal;

(2)

the

middle

ear

connective

tissue

layer,

b e 3 . 5 m m for a n o p e n c a v i t y , 4 m m i f t h e m a l l e u s

continuous with both the connective tissue layer of

h a n d l e is p r e s e n t , or 5 mm if it is a b s e n t .

the external ear canal and

A thin but large piece of cartilage is placed over the T O R P ( b e n e a t h brane

graft)

to

the

malleus or tympanic mem-

provide

protection

from

extrusion

inner

mucosal

layer,

m i d d l e ear; a n d (3)

continuous

with

that

of

the the

middle ear. T h e higher magnifications (Figs, 12-17, 1 2 - 1 8 ) clearly s h o w the i n g r o w t h o f o u t e r stratified

( s o m e s u r g e o n s suture it to the T O R P ) . If there is a

squamous

footplate or m e m b r a n e , the T O R P is placed o v e r it

removed

and

graft; o t h e r w i s e t h e r e will b e n o m i g r a t i o n o f e p i t h e -

is supported

it in

position.

provide more

with

abundant Gelfoam

A T O R P with a stability at the

to secure

p e g can be u s e d

(arrows).

placement

This

of

a

epithelium

connective

is

tissue

lial c e l l s o v e r t h e g r a f t . T h e p u r p o s e o f t h e g r a f t i s

prevent

to " r e p l a c e " the lost c o n n e c t i v e tissue a n d to serve

slipping (Fig. 1 2 - 1 5 A ) . O n c e the T O R P is placed, it

as a b r i d g e for m i g r a t i o n of e p i t h e l i a l c e l l s to c l o s e

tension

footplate and

to

epithelium before

should

impart s o m e

brane.

A T O R P - s h a p e d piece of cartilage or cortical

to

the

tympanic mem-

the g a p ( p e r f o r a t i o n ) . T h e s e p h o t o m i c r o g r a p h s illustrate

the c o n c e p t s of perforation and grafting; they

b o n e can be used, as well. A small piece of Silastic

are

can be placed, s u r r o u n d i n g the prosthesis at the oval

perforation during an a c u t e e p i s o d e of otitis media,

w i n d o w area, in o r d e r to prevent a d h e s i o n s (Fig. 1 2 -

even if s u p e r i m p o s e d over a chronic process.

not

meant

to

imply

or

to

suggest

grafting

a

244

Tympanoplasty

Tympnnoplasty

.) EXlerna! ear canal .~

External ear canal

,"""

FIGURE 12-17.

245

246

Tympanoplasty

CHAPTER 13 Surgery for Stapes Fixation S t a p e s procedures aim to re-establish s o u n d transmission dary

through

to'

a

fixation

involve partial replacement

stiffened ossicular chain, of

the

or total

with

stapes. removal

mobile

These of

portions

secon-

procedures

without

however,

of

of

it

or

with

a

for

speculum

holders;

speculum holders are

used by a

majority

surgeons.

the

Tjhe

need

authors

prefer

a

procedures

that

have

been

used

ap-

is not hard

to stabilize

at

hand

right-handed surgeon),

here.

Although

a

detailed

description

is

A

well-fitted ear s p e c u l u m holds in place quite well. It

s u c c e s s f u l l y for s t a p e s fixation will not be d i s c u s s e d length

transcanal

proach, u s i n g an ear s p e c u l u m w i t h o u t a holder.

surgical

(for a

the

speculum with while

t h e left using an

b e y o n d the scope of this atlas, the reader should be

i n s r u m e n t (such as a suction tip) at the s a m e time.

a w a r e of t h e m . T h e y are (1) fenestration of the lateral

The procedure

semicircular canal, and (2) sonoinversion. Fenestra-

ulum; o n c e the incisions h a v e b e e n m a d e , a tightly

tion o f t h e lateral s e m i c i r c u l a r c a n a l a l l o w s v i b r a t i o n s

fitting o n e is u s e d .

to reach

the

hair cells t h r o u g h

bypassing the ossicular chain,

the scala

smaller spec-

S m a l l e x o s t o s e s o f t h e c a n a l (if a n y ) a r e r e m o v e d . should

stapedectomy

by

a

(If t h e y a r e l a r g e o r i f a c a n a l p l a s t y i s n e c e s s a r y , t h i s

has

replaced

with

with a resultant mild

a i r - b o n e g a p o f 2 5 t o 3 0 dF3. A l t h o u g h t h i s p r o c e d u r e been

can be started

vcstibuli,

stapedectomy,

it

should

be

kept in m i n d . It can be of use in s o m e unusual cases

be

done

as

a

separate

delayed

until

procedure

complete

and

the

healing

has

been achieved, which could be a matter of months.)

of otosclerosis, as an interval operation in s o m e forms

It should be r e m e m b e r e d that entrance to the middle

of

ear

tympanoplasty,

as a surgical FIGURE 12-1K

surgery

this ossicle and

prosthesis. Two

S o m e s u r g e o n s prefer a small endaural approach, since it provides good exposure and allows bimanual

and

could

eventually

re-emerge

t e c h n i q u e for d e l i v e r y of d r u g s to the

must

be

made

in

a

dry

field

and

beneath

the

annulus. F r o m this point on, the m i c r o s c o p e is used

inner ear. Sonoinversion (technique of Garcia-Ibanez)

at a magnification of at least 10

delivers

there are three basic types of stapedectomy—partial,

vibratory

stimulation

through

the

round

w i n d o w m e m b r a n e by utilizing a prosthesis from the

total,

incus or malleus to the round w i n d o w . T h e normal

general

mechanism of sound

described

transmission

via

the ossicular

chain to the oval w i n d o w is successfully " i n v e r t e d . " T h e basic head position with slight hypertension and

the

transcanal

approach

have already been

and

piston.

approach, on

the

The and basis

x. In general terms

procedure the of

here

different the

will

types

findings

be

will

and

a be

their

indications O n c e t h e a n n u l u s i s e l e v a t e d , t h e first o b j e c t i v e i s

de-

to obtain a d e q u a t e e x p o s u r e and then to e x p l o r e the

s c r i b e d ; t h e d i s c u s s i o n will f o c u s o n p r o c e d u r e s after

ear. W o r k on the stapes is the final step, a n d is only

the a n n u l u s has b e e n elevated.

begun

S t a p e s p r o c e d u r e s g e n e r a l l y are d o n e u n d e r local anesthesia can be

with

used;

preventing

sedation.

however,

the

surgeon

it

General has

from

the

anesthesia

also

disadvantage

monitoring

of

vestibular

s y m p t o m s or hearing gains in the operating room.

after all o t h e r w o r k is c o m p l e t e d .

A

useful

rule o f t h u m b for e x p o s u r e o f t h e o v a l w i n d o w i s t o achieve clear visualization of the pyramidal e m i n e n c e a n d t h e s u p e r i o r a s p e c t o f t h e facial n e r v e . M o s t o f the

time,

posterior

this canal;

requires in

removal

doing

so,

of

the

bone chorda

from

the

tympani

249

S u r g e r y for S t a p e s F i x a t i o n m u s t be freed. U s u a l l y a fine n e e d l e can be u s e d to

On

the b a s i s o f t h e s e o b s e r v a t i o n s a n d t h e pref-

mobilize the chorda anteriorly toward the incus (Fig.

erence and

13-1/1').

surgical

If

maneuver,

the

chorda

will

be

stretched

it is b e t t e r to s e c t i o n

by

this

it s h a r p l y with

a

Bone

of

curetted. stapes

the

The

curets

posterior

authors in

canal

prefer

strokes

can from

ossicles).

O n c e visualization has been achieved,

footplate

is

to

be

removed,

and

a

membrane

If a p r o s t h e s i s will be e m p l o y e d , a firm a n d l a s t i n g contact m u s t be established with the long process of

re-

the incus (or the m a l l e u s handle).

13-1B).

all a n a t o m i c

The presence of an open round window is imporDrilling a round

the

large

l a n d m a r k s are i n s p e c t e d (Fig. 1 3 - 1 Q . tant. T o t a l o b l i t e r a t i o n will lead

of

ossicles

Meticulous

moval of b o n e chips should be d o n e (Fig.

the specific

Regardless

( p r e f e r a b l y c o l l a g e n o u s ) u s e d i n its p l a c e for a s e a l .

with

the

selected.

or

drilled

to curet it

away

(avoiding luxation of the

be

is

p r o c e d u r e , t h e u n d e r l y i n g i d e a i s t h a t all o r p a r t o f the

knife or a Bellucci scissors (Fig. 1 3 - 1 / 1 ) .

experience of the surgeon,

procedure

to a p o o r e r result.

Total Stapedectomy with Prosthesis

w i n d o w also leads to poor results

and complications a n d is not r e c o m m e n d e d . A very s m a l l o p e n i n g (»70/ s u r g i c a l l y i n d u c e d ) i n t h e w i n d o w s h o u l d suffice for a s a t i s f a c t o r y o u t c o m e ; t h i s s h o u l d be

kept in mind.

However,

in

some

patients

with

obliterated round w i n d o w s s o m e gain in hearing can be obtained; since such an improvement might make a s i g n i f i c a n t d i f f e r e n c e in their l i v e s , a s t a p e d e c t o m y should The

be attempted. ossicular

chain

is

then

palpated

(using

an

angled hook or H o u g h hoe) in order to locate points of ossicular fixation (Fig. 1 3 - 1 D , E ) . Special attention is paid to cases of unilateral hearing loss, in which nonotosclerotic fixations are m o r e frequent. Fixation of

the

malleus

fixation

is

atticotomy

at

most the

often

head.

(previously

is

congenital,

This

finding

described)

the h e a d of the m a l l e u s (Fig.

and

the

requires

an

and exposure

of

T h e c l a s s i c total s t a p e d e c t o m y i s u s e d h e r e a s the primary procedure to describe general principles and problems encountered

during surgery. T h e descrip-

tion a s s u m e s that t h e r e i s n o n o b l i t e r a t i v e fixation o f the stapes,

the rest of the ossicles are m o b i l e ,

the

round w i n d o w is patent, a n d the oval w i n d o w is of norma! size. T h e distance between the incus and the footplate

is

measured.

The

average

measurement

from the h e a d of the stapes to the footplate is 3.29 mm

±

0.15

mm,

to w h i c h

is added

1

mm

of

the

lenticular process. T h e average length of a prosthesis is 4.0 mm in w o m e n and 4.25 to 4.50 mm in men. If a wire c o n n e c t i v e tissue p r o s t h e s i s is to be u s e d , it should

be

made

at

this

time.

Connective

tissue

should be h a r v e s t e d at this point as well.

13-2/1). The authors

p r e f e r to u s e c u r e t s , b u t if a drill is u s e d , t h e i n c u s should be separated from the head of the stapes with a

joint

knife

in

order

to

avoid

acoustic

Attachments can sometimes be released,

and small

pieces of Silastic can be placed to avoid fixation (Fig. 13-26); however, mal,

Harvesting a Graft

trauma.

u n l e s s the a t t a c h m e n t s are mini-

this is usually f o l l o w e d by refixation.

A solid

O n c e the stapes has been removed,

the vestibule

is e x p o s e d and a n e w m e m b r a n e is n e e d e d to seal the o p e n i n g . C o n n e c t i v e tissue, specifically collagen,

fixation requires r e m o v a l of the h e a d of the m a l l e u s

allows the formation of a stable seal

with m a l l e u s n i p p e r s (Fig. 1 3 - 2 C ) a n d p l a c e m e n t of

part o f t h e w i n d o w . W h i l e G e l f o a m s t i m u l a t e s tissue

a m a l l e u s to oval w i n d o w p r o s t h e s i s , a b o n e strut,

growth a n d is u s e d satisfactorily by m a n y surgeons,

or a

(TORP)

these m e m b . a n e s tend to be thin and carry a higher

(Fig. 1 3 - 2 D - F ) . ( S e e a l s o C h a p t e r 1 4 for a l t e r n a t i v e

r i s k o f f i s t u l a f o r m a t i o n a n d p e r i l y m p h l e a k a g e . Dif-

procedures utilizing a laser.)

f e r e n t s o u r c e s a r e u s e d , s u c h a s fat a n d c o n n e c t i v e

total

Under

ossicular replacement prosthesis

10

X

or

16

x

magnification,

the

oval

tissue from the earlobe or postauricular area,

w i n d o w and stapes are inspected (Fig. 1 3 - 3 ) . Is there

perichondrium,

a

and

normal-sized

oval

window,

a

promontory

over-

tissue

over

footplate?

Is

there

a

vein.

prostheses,

and

is

T i s s u e from used

tragal

the earlobe

for w i r e c o n n e c t i v e

from p e r i c h o n d r i u m or vein

stapedial

as sealing m e m b r a n e s with simple wires or pistons.

artery? Is the s t a p e s fixed anteriorly or posteriorly?

Type of prosthesis, ease of handling, and individual

I s t h e f o o t p l a t e o f n o r m a l size ( o n a v e r a g e , 1.4 m m

p r e f e r e n c e s will d e t e r m i n e s u c h c h o i c e s

wide a n d 3 . 0 mm long)? Is part,

persistent

or a

postauricular area

h a n g , or a d e h i s c e n t facial n e r v e ? Is t h e facial n e r v e the

that b e c o m e s

h a l f , o r all o f t h e

A s m a l l i n c i s i o n s u f f i c e s for h a r v e s t i n g t i s s u e f r o m

f o o t p l a t e i n v o l v e d ? Is t h e r e obliteration of the foot-

the e a r l o b e or postauricular area (Fig.

plate a n d w i n d o w b y otosclerotic foci?

incision is closed with o n e or two appropriate sutures

13-4A, 6 ) . T h e

250

S u r g e r y for S t a p e s F i x a t i o n

S u r g e r y for S t a p e s F i x a t i o n

FIGURE 13-3.

FIGURE 13-2.

251

S u r g e r y for S t a p e s Fixation

253

a n d t h e t i s s u e i s left i n s a l i n e s o l u t i o n . T r a g a l p e r i -

incus) large • or s h o r t e r , a c c o r d i n g to the size of the

chondrium

long process of the incus.

is

obtained

via a

small

incision in

the

The wire-cutting scissors

undersurface of the tragus, exposing the perichon-

a r e slid u p t o t h e k n o t i n t h e m i d d l e o f t h e g r a f t a n d

d r i u m , w h i c h c a n b e p e e l e d off t h e u n d e r l y i n g c a r -

the wire is sectioned.

tilage (Fig.

unless

1 3 - 4 C ) . Meticulous hemostasis is done,

the

N o s h a r p e n d s s h o u l d b e left

patient has

otosclerosis associated

the incision is closed with t w o or t h r e e a p p r o p r i a t e

endolymphatic hydrops;

sutures,

posely

and

the

perichondrium

is

gently

pressed

left

sharp

in

might

this c a s e ,

work

as

a

an end

with pur-

"conservative

a n d r i n s e d i n s a l i n e . All i n s t r u m e n t s a n d m a t e r i a l s

t a c k . " T h e p r o s t h e s i s i s left i n s a l i n e u n t i l u s e .

u s e d in this a r e a s h o u l d be rinsed in o r d e r to r e m o v e

5-mm

any particles from their surfaces.

in Figure 1 3 - 5 D .

Vein hand

can

by

a

be

harvested

small

from

incision.

the

d o r s u m of the

Both e n d s are carefully

malleus-to-oval

window

prosthesis

is

A

shown

T h e m a k i n g of a wire piston is s h o w n in Figure 1 3 - 6 ; the t e c h n i q u e (after Rosales) is self-explanatory

tied; t h e m i d s e c t i o n of t h e vein (size as n e e d e d ) is removed

and

split

open,

the

endothelial

layer

is

r e m o v e d , a n d the vein is pressed a n d rinsed in saline (Fig.

13-4D).

In

general,

the

adventitial

layer

placed facing the vestibule. W i t h p e r i c h o n d r i u m , the side

in

direct contact

with

the

cartilage

is

Procedure

is

placed

facing the middle ear; o t h e r w i s e small cartilage r e m n a n t s m a y fall i n t o t h e v e s t i b u l e , p o t e n t i a l l y c a u s i n g complications.

T h e footplate is f r a c t u r e d at the midline with a needle (Fig. 1 3 - 7 4 ) . C r e a t i n g a hole in the footplate is f r e q u e n t l y d e s c r i b e d , b u t for a total s t a p e d e c t o m y an a c t u a l f r a c t u r e is b e t t e r a n d p r e v e n t s a floating footplate. T h e m u c o s a is not elevated at the footplate; this a v o i d s bleeding a n d h e l p s to p r e v e n t small, loose f r a g m e n t s f r o m falling i n t o t h e v e s t i b u l e . I f t h e r e i s

Making the Prosthesis

bleeding,

small pieces of G e l f o a m s a t u r a t e d with a

s o l u t i o n o f MOOO e p i n e p h r i n e a r e a p p l i e d t o p i c a l l y . A N o . 2 4 s u c t i o n tip w i t h t h e f i n g e r off t h e h o l e i s Many

satisfactory

available. Celfoam

Except

prostheses

for

prostheses

polyethylene

will

geon's

preference

m a d e at that

on

tissue

surgery.

have

stood

c o n n e c t i v e tissue

wire

used.

It

cannot

be

emphasized

higher

all t i m e s .

pistons

(which

can cause a "dead ear."

the vast majority of

surgical

used.

that

the

Suctioning p e r i l y m p h in the oval w i n d o w

T h e i n c u d o s t a p e d i a l joint is gently s e p a r a t e d with a joint knife (Fig.

1 3 - 7 8 ) ; t h e k n i f e i s slid b e t w e e n

the incus a n d the h e a d of the stapes to e n s u r e that

the

sur-

wire

and

separation is total. T h e stapedial t e n d o n is sectioned

be

with t h e joint knife or a Bellucci scissors (Fig. 1 3 - 7 C ,

T h e s e are the classic prostheses

D). S o m e t i m e s it is possible to g e n t l y peel it a l o n g

and and the

findings a n d

Their

enough

s u c t i o n tip m u s t s t a y a w a y f r o m t h e o v a l w i n d o w a t

have a

satisfactory if properly

depend

connective

struts and

to

tend

t e n d to c a u s e local r e a c t i o n s ) , use

commercially

Plastipore

(which

i n c i d e n c e of fistulae) a n d prostheses are

are

experience. wire test

Teflon of

Both

pistons

time.

The

prosthesis can be

can

wire

tailored

to

and the

with the m u c o p e r i o s t e u m a n d

leave it attached

to

the long p r o c e s s of t h e incus (Fig. 1 3 - 7 E , F ) . This

needed length or bent or c u r v e d in n a r r o w w i n d o w s

allows

o r p r o m i n e n t facial n e r v e s ; i t a l s o p r o v i d e s a n e x c e l -

p e r m i t s better vascularity to the long p r o c e s s of the

lent seal.

incus. In the unusual e v e n t of a p r o m i n e n t pyramidal

The

technique

for

making an

of c o n n e c t i v e

some

protection

from

sound

and

win-

eminence, the tendon is sectioned and the eminence

1 3 - 5 . A piece

curetted. T h e head and c r u r a of the stapes (stapedial

incus-to-oval

d o w prosthesis is depicted in Figure

perhaps

t i s s u e is c u t to a size of 2

x

3 mm.

arch) are mobilized with an angled hook toward the

This is p l a c e d on the e d g e of the die a n d is tied at

p r o m o n t o r y a n d not i n a n a n t e r o p o s t e r i o r d i r e c t i o n

its m i d p o r t i o n w i t h a 0 . 0 0 5 - m m s t a i n l e s s s t e e l w i r e

( w h i c h c a n c a u s e p a r t o f t h e footplate t o d r o p into

(Fig.

the oval w i n d o w ) . Usually the arch fractures at the

13-5/1).

A d r o p of saline helps handling a n d

placing of the tissue in the desired position. W i t h an

junctions

alligator forceps h o l d i n g both e n d s , t h e k n o t is tight-

removed

ened

forceps (Fig. 1 3 - 7 G ) . M e a s u r e m e n t s a r e n o w m a d e

until it d i s a p p e a r s into the c o n n e c t i v e tissue

The wire is looped a r o u n d the larger post of the die

(Fig.

of with

the

crura

with

the angled

the

footplate,

hook or a

and

is

baby alligator

13-7H).

at 4 mm

At this poi.it, the patient is i n s t r u c t e d not to m o v e

T h e connective tissue end is rotated

o r talk. S i m i l a r r e c o m m e n d a t i o n s a p p l y t o t h o s e i n

with

the bottom of the connective

(Fig.

13-58).

tissue

1 3 - 5 C ) . Wire-cutting

the o p e r a t i n g r o o m . T h e footplate is r e m o v e d with a

scissors a r e used to cut the loop (to h o o k into the

H o u g h h o e or a right-angled h o o k (Fig. 1 3 - 8 4 ) . It is

a r o u n d the smaller post (Fig.

254

Surgery for Stapes Fixation

Surgery lor Stapes Fixation

Gelloam

._{f-. . . -,. . -,-,- ~ 0.005 starnless steel wire

A '"

1---4mm--j B

o FICURE 1:\-5

Malleus to oval window

FlCURE 13-.

255

256

S u r g e r y for S t a p e s Fixation

S u r g e r y for S t a p e s F i x a t i o n

257

important to place the instrument just barely beneath

( X y l o c a i n e ) w i t h e p i n e p h r i n e s h o u l d >iof b e u s e d i n

the

the open vestibule since it can cause m a r k e d vestib-

fragments

to

be

removed

in

order

to

avoid Bone

ular d i s t u r b a n c e s . T h e p r e s e n c e o f a n a b n o r m a l j u g -

removed

ular bulb has been described in another chapter; if

damaging the underlying vestibular structures. fragments

are

either

totally

or

partially

(usually by r e m o v i n g the posterior t w o thirds of the

its

footplate), depending upon the procedure to be done

procedure,

(Fig.

persistent

13-8A).

With an alligator forceps or a horizontal o p e n i n g forceps

(which

allows

better visualization)

holding

location

allows it

a

should

stapedial

safe not

exploration

be

artery

a

and

stapes

contraindication.

(running

over

the

A

foot-

p l a t e ) is a v e r y u n u s u a l f i n d i n g . T h i s a r t e r y is fairly large

and

shojld

not

be

confused

with

small

but

the prosthesis is placed

prominent mucoperiosteal vessels in the footplate. If

(Fig. 1 3 - 8 B ) . If it c a n n o t be placed easily in position,

a small o p e n i n g on the footplate can be m a d e and a

it is r e l e a s e d a n d m o b i l i z e d b i m a n u a l l y (for e x a m p l e ,

small

with the s u c t i o n tip a n d a H o u g h h o e ) . If the w i r e is

otherwise, the operation should not take place.

the bare edge of the wire,

bent

during

positioning,

it

is better to

use a

new

p r o s t h e s i s t h a n t o fix it. T h e o v a l w i n d o w s h o u l d b e left

open

time

of

for

the

shortest

exposure

hearing.

excessive effects

done;

Obliteration of the r o u n d w i n d o w and fixation of the malleus have been described. Accidental

Dislocation

of

the

Incus.

The

incus

should

on

be palpated. If the dislocation is partial a n d the incus

d o w p r o s t h e s i s (or an e q u i v a l e n t prosthesis,

tissue is u s e d , the o v a l w i n d o w graft is p l a c e d b e f o r e

scribed in C h a p t e r 12) is substituted.

(Fig.

13-8C).

Such

a

is

be

u s u a l . If it is totally l u x a t e d , a m a l l e u s - t o - o v a l w i n -

precisely;

tissue

can

seal the w i n d o w . If a prosthesis without connective

fit

connective

to

procedure

moves with the malleus, the prosthesis is placed as

prosthesis

wire

possible;

related

the

well

should

the

time

directly

placed,

centered, additional connective tissue can be used to

the

Once

is

piston

graft

ideally

it cannot be too small

or too

Fracture crimping

of

the

the

long

process of the

prosthesis

as de-

incus

while

is rare; if it h a p p e n s ,

the

large. If a piston is used, c o n n e c t i v e tissue is w r a p p e d

prosthesis

a r o u n d it. S m a l l p i e c e s o f G e l f o a m c a n t h e n b e p l a c e d

(Fig. 1 3 - 9 4 ) . If this is i m p o s s i b l e , a malleus-to-oval

over the c o n n e c b v e tissue and around the prosthesis.

window

Piston w i d t h in a s t a p e d e c t o m y is from 0.6 to 0.8

instead.

m m , w h e r e a s in a s t a p e d o t o m y (described b e l o w ) , it is 0 . 4 m m . or an alligator forceps. T h e crimper has the advantage of not closing completely; thus there is less c h a n c e

be

crimped

prosthesis

on

the

remaining

(or its e q u i v a l e n t ) c a n

strut

be

used

Pain. A n o c c a s i o n a l p a t i e n t m i g h t c o m p l a i n o f p a i n when

T h e prosthesis is crimped with a M c G e e crimper

can

the

middle

application

ear

mucosa

of ':.% lidocaine

is

in

touched.

cotton

Topical

or

Gelfoam

drilled

carefully

pledgets suffices. Prominent

Promontory.

This

can

be

of fracturing the long process of the incus (Fig. 1 3 -

i n o r d e r t o pro* ide a d e q u a t e v i s u a l i z a t i o n (Fig.

8D).

9C).

It is a l s o light a n d thin a n d d o e s n o t obstruct

13-

D e p e n d i n g upon the visualization obtained, a

vision. C r i m p i n g is d o n e in an anteroposterior direc-

small piston or A wire c o n n e c t i v e tissue prosthesis is

tion

placed.

and

involves only

otherwise,

the

ring

around

the

incus;

t h e p r o s t h e s i s will b e b e n t a n d will h a v e

An

abnormal

(open

or

redundant)

n e r v e in itself is not a c o n t r a i n d i c a t i o n .

to be changed. Teflon wire pistons bend very easily

possible

if n o t c r i m p e d properly. T h e r o u n d w i n d o w reflex,

a l l o w i n g a n o p e n i n g t o b e m a d e i n t h e f o o t p l a t e for

the mobility of the ossicular chain, and the adequacy

placement

of the prosthesis position are c h e c k e d at this point,

upon

after w h i c h

the flap Is r e p o s i t i o n e d .

T h e patient is

the

to

mobilize of

a

it

gently

prosthesis.

anatomic

with

a

seventh

It m a y be

blunt

Sometimes,

conditions,

a

wire

hook,

depending connective

t i s s u e p r o s t h e s i s c a n b e b e n t t o fit. O n o c c a s i o n , a n

then asked if there is a n y i m p r o v e m e n t in hearing.

o f f s e t R o b i n s o n p r o s t h e s i s fits p r e c i s e l y .

Finally, the ear canal is packed (described below).

a n d u s e o f a p r o s t h e s i s t o fit t h e n e e d a r e p a r a m o u n t ;

Flexibility

the c o u r s e of action s h o u l d reflect the a n a t o m i c and functional n e e d s of the patient and the rational and

Problems and Variations During Surgery

safe a p p r o a c h o f the s u r g e o n . Narrow

Oval

Window.

can

also

represent

u n c o m m o n l y leads Bleeding. S m a l l v e s s e l s r e s p o n d v e r y w e l l t o t o p i c a l

FIGURE 13-7

A

narrow

window

can

be

s e c o n d a r y to a p r o m i n e n t overlying p r o m o n t o r y ; it a

congenital

to a

defect,

perilymph

which

"gusher."

not It

is

a l s o v e r y i m p o r t a n t t o a s s e s s t h e facial n e r v e a n d its

application of cotton balls or Gelfoam saturated with

relationship

epinephrine.

w i n d o w itself is quite narrow a n d a congenital defect

In the footplate it is preferable to use

Gelfoam in order to avoid cotton strands. Lidocaine

is s u s p e c t e d ,

to

the

footplate

(Fig.

13-9D).

If

the

a small o p e n i n g can be m a d e with a

258

Surgery for Stapes Fixation

Surgery for Stapes Fixation

A

A

c

HGURE 1:1-8

FIGURE 13-9.

259

261

S u r g e r v for S t a p e s Fixation

small, s h a r p n e e d l e ; if a g u s h e r is f o u n d , it is c o v e r e d

is

with c o n n e c t i v e t i s s u e a n d G e l f o a m . T h e h e a d o f t h e

delay such procedures but s o m e surgeons do perform

not an e a s y one; in general,

patient is raised a n d the p r o c e d u r e is t e r m i n a t e d . If

them, reportedly with g o o d results.)

there is no g u s h e r , the small o p e n i n g c a n be e n l a r g e d to place a 0 . 4 - m m p i s t o n or a t h i n p r o s t h e s i s . Cerebrospinal

Fluid

Leak.

or

diamond

bur

with

slow

rotation

and is g e n e r a l l y (but not e x c l u s i v e l y ) s e e n in c a s e s

izing e v e n l y and applying just e n o u g h pressure over

of a c o n g e n i t a l l y fixed s t a p e s ( a n d a p a t e n t c o c h l e a r

the

aqueduct). T h e patient's h e a d is elevated a n d a large

lously r e m o v e d . If the footplate is t h i n n e d e v e n l y (to

connective

a

prosthesis

is

cutting

(Fig. 1 3 - 1 1 8 ) . T h i s is d o n e anteroposteriorly, saucer-

wire

"gusher"

A thick footplate m u s t be t h i n n e d with a 0 . 6 - to 1-mm

uncommon,

tissue

A

it s e e m s better to

used

for a

seal,

with a d d i t i o n a l c o n n e c t i v e tissue. Dry Vestibule.

footplate

thin

to be effective.

bluish

plate),

a

Bone

small

dust is meticu-

(0.5-mm)

opening

is

m a d e a n d a piston s u r r o u n d e d by c o n n e c t i v e tissue

If t h e p e r i l y m p h is a c c i d e n t a l l y s u c -

i s p l a c e d (Fig. 1 3 - 1 1 C - E ) . L e s s c o m m o n l y , the foot-

tioned o u t o f the oval w i n d o w (the s u c t i o n tip s h o u l d

plate is fractured a n d r e m o v e d , a n d a graft is placed.

nettcr b e p u t i n t o t h e o v a l w i n d o w [ F i g . 1 3 - 1 0 E , F ] ) , the w i n d o w will refill. If it d o e s n o t , a f e w d r o p s of s a l i n e a r e u s e d t o fill it.

Blood m i g h t stimulate an

inflammatory reaction in the vestibule. Floating

Footplate.

This

refers

to

a

footplate

Stapedotomy

that

becomes mobile before an opening is m a d e in it and after r e m o v a l o f t h e a r c h ( t h e s u p e r s t r u c t u r e c o n s i s t ing o f t h e h e a d a n d c r u r a ) . T h i s i s a difficult c h a l lenge. O n e w a y to a v o i d it is to fracture the footplate before r e m o v i n g t h e a r c h . A floating footplate t e n d s to occur in a s t a p e s that has b e e n previously mobilized o r i n o n e w i t h p o o r f i x a t i o n . S o m e t i m e s the footplate can be carefully r e m o v e d with a n a n g l e d h o o k . I f t h i s i s i m p o s s i b l e , a n o p e n i n g can be m a d e w i t h a d i a m o n d b u r or s m a l l b u r in the anteroinferior

margin,

and

the

footplate

removed

with a h o o k (Fig. 1 3 - 1 0 4 , 8 ) . If this t o o is i m p o s s i b l e and

the

placed

footplate over

refixation

it

not

and

occurs

can b e r e v i s e d

is

a

depressed, shorter

(which

is

fascia

piston

likely),

This

procedure

advocates

a d h e s i o n s b e t w e e n the graft a n d vestibular c o n t e n t s , and less mobility of the oval w i n d o w as a w h o l e . As with

all

surgical

innovations,

time and

experience

will tell. T h e p r o c e d u r e a l s o c a n be d o n e with a laser (see C h a p t e r 14). T h e operation is similar to a classic stapedectomy,

u p t o t h e p o i n t o f o p e n i n g t h e foot-

plate. T h e n the footplate is perforated with a sharp needle (or special microdrill) in three different spots. E n l a r g e m e n t of these o p e n i n g s is d o n e very carefully

placed.

If

o p e n i n g that is slightly larger than 0.4 m m . T h e size

footplate

can be m e a s u r e d with a 0 . 4 - m m measuring rod. This

the

with angled

fragments

can

be

hooks,

trying to leave a single central

step can be d o n e without removing the stapes arch, mobilization

of

the

stapes.

Once

c r u r a a r e sectioned w i t h c r u r o t o m y s c i s s o r s ;

vestibule s h o u l d be a v o i d e d ; it is better to leave the

thesis

fragments

footplate

the vestibule and

use ample amounts

of steroids, topically and parenterally. S o m e authors recommend

placing

a

few

drops

of

blood

in

this

is

d o n e , the incudostapedial joint is s e p a r a t e d and the

removed carefully with a hook, but " f i s h i n g " in the in

in

involves less risk of inner ear d a m a g e , less c h a n c e of

avoiding Depressed

many

be

with better c h a n c e s of s u c c e s s (Fig

Fragments.

gained

can

13-10C). Depressed

has

recent years b e c a u s e it has b e e n suggested that it

is

then

placed

opening

and

over

the

incus

surrounded

and

with

the prosinto

the

connective

tissue.

the

vestibule a n d a l l o w i n g t h e m to clot; w h e n t h e clot is removed the fragments m a y c o m e out with it (Fig. 13-10D).

Stapes Interposition

Obliterative Otosclerosis

In the p r e s e n c e of a wide niche, an anterior fixation,

and a healthy posterior crus,

procedure If an obliterative focus is f o u n d — f o r e x a m p l e , if

is a

rational alternative.

an interposition It

represents

a

safe a n d logical a p p r o a c h b u t is difficult to p e r f o r m

the o v a l w i n d o w h a s n o d i s c e r n i b l e f o o t p l a t e o w i n g

properly, requiring ability and e x p e r i e n c e . T h e pro-

to otosclerotic c h a n g e (Fig. 1 3 - 1 1 4 ) — t h e p r o c e d u r e

cedure involves removing a portion of the footplate

is different.

(fixed) a n d mobilizing the posterior crus (as a "pros-

focus,

it

is

If the p a t i e n t is a c h i l d w i t h an active better

to

delay

question of operating on

!

this

children

procedure. with

(The

otosclerosis

t h e s i s " ) o v e r an u n d e r l y i n g graft, t h u s re-establishing the continuity and mobility of the ossicular chain.

S u r g e r y for S t a p e s Fixation Initially the anterior crus is s e c t i o n e d with a n g l e d c r u r o t o m y scissors (Fig.

1 3 - 1 2 / 1 ) . P o r t m a n n (an ad-

263

thesis, but it is p l a c e d at a right a n g l e to the m a l l e u s handle (Fig.

13-146).

O n c e it is over the malleus

vocate of this p r o c e d u r e ) r e c o m m e n d s sectioning in

handle

the main axis of the stapes, introducing the scissors

d o w n so that it is p e r p e n d i c u l a r to the handle; this

b e t w e e n the malleus a n d the incus, since the simpler

m a n e u v e r m a k e s positioning easier.

approach through the p r o m o n t o r y carries the risk of

satisfactory,

fracturing the stapes at a n o t h e r site. T h i s is followed

the

by sectioning of the stapedial tendon. T h e posterior

graft i s p l a c e d o v e r t h e o v a l w i n d o w . T h e p r o s t h e s i s

crus is t h e n carefully fractured with a m i c r o h o o k at

is

its j u n c t i o n

W h e n the posterior

a n a n g l e d h o o k a n d s u c t i o n tip o r b l u n t i n s t r u m e n t )

crus is free (from m u c o s a l a d h e s i o n s as w e l l ) , it is

along the undersurface of the malleus (Fig. 1 3 - 1 4 C ) .

m o b i l i z e d a n t e r i o r l y w h i l e the i n c u s is lifted w i t h a

It

H o u g h h o e (thus avoiding fractures in the posterior

well the prosthesis m i g h t fit, it is anatomically a n d

crus) (Fig. 1 3 - 1 2 B ) . T h e footplate is fractured a n d the

functionally less efficient than a s t a p e d e c t o m y pros-

posterior t w o thirds are r e m o v e d (Fig.

1 3 - 1 2 C and

thesis; at the s a m e time, the oval w i n d o w is subjected

Fig. 1 3 - 1 3 A ) . A graft is p l a c e d a n d t h e p o s t e r i o r c r u s

to m o r e trauma (the mobility of the malleus is greater

is

than that of the incus a n d has less d a m p e n i n g effect).

with

repositioned

lifted),

the footplate.

over

the

graft

(while

the

incus

re-establishing ossicular continuity and

is

(under

the

footplate positioned

should

the

be

is

periosteal

prosthesis removed,

and

then

is

pocket),

turned

anteriorly,

connective

tightened

that,

is

If the length is

displaced

and a

remembered

it

tissue

bimanually

regardless

(with

of h o w

mo-

bility (Fig. 1 3 - 1 3 B - D ) . S o m e s u r g e o n s perform this p r o c e d u r e b y r e m o v ing part of the a n t e r i o r crus a n d the anterior half of

Closure and Packing

the footplate (an anterior c r u r o t o m y ) . T h e r e m a i n i n g mobile plate

posterior

are

crus

mobilized

and

underlying

toward

the

mobile

center of

foot-

the

oval

T h e flap is carefully r e p o s i t i o n e d . If a small tear is

w i n d o w (over the graft). T h e stapedial tendon might

present,

or

necessary,

might

posterior

not

be

sectioned,

crurotomy

also

according

can

be

to

done

need.

in

A

reverse

the

edges

small

are

carefully

pieces

approximated.

of Gelfoam

or

If

connective

t i s s u e c a n b e u s e d , a n d t h e flap left s o m e w h a t l o o s e .

fashion, but usually the point of footplate fixation is

For larger perforations,

anterior.

a m o u n t s of antibiotics and anti-inflammatory medications are used. scribed.

a graft is p l a c e d a n d a m p l e

Packing techniques h a v e b e e n de-

T h e p a t i e n t m u s t lie w i t h t h e o p e r a t e d ear

up and is closely followed postoperatively; the need

Malleus-to-Oval Window Prosthesis

to a v o i d straining, lifting, or u n d u e effort c a n n o t be emphasized enough.

Complications continue

to be

v e r y p o s s i b l e until c o m p l e t e h e a l i n g h a s o c c u r r e d (at four The

aim

of

this

procedure

a

weeks)

and

may

still

occur

thereafter.

prosthesis from the h a n d l e of the malleus to the oval

operative procedure. It has been argued that prophy-

window.

lactic antibiotics are u n n e c e s s a r y ; h o w e v e r ,

place

place

six

S o m e failures can be traced to o v e r c o n f i d e n c e in the

to

to

to

wire

It is i m p o r t a n t

is

the wire u n d e r a

the au-

J

subperiosteal pocket in the handle of the malleus, as

thors strongiy r e c o m m e n d the use of intraoperative

close to the short process as possible.

and postoperative antibiotics.

Such prostheses are commercially available, but a wire connective tissue can be m a d e . S t a p e s prosthesis wire and

a

b e n d i n g die are

used

to

manufacture a

prosthesis; only the large post of the die is used to

Complications

shape the " c r o o k " or " h a n d l e " (see Fig. 1 3 - 5 ) . With

a joint knife,

an

incision

is

made

through

the m u c o p e r i o s t e u m on the undersurface of the handle of the malleus, (Fig.

13-14/1).

of contact to

place

with

creating a

subperiosteal

pocket

On occasion it is necessary (because the overlying tympanic m e m b r a n e )

the prosthesis at the

neck of the

malleus.

A s i n a n y surgical p r o c e d u r e , a w a r e n e s s a n d prevention of possible c o m p l i c a t i o n s are the keys. nosis,

a n d rational surgical plans are of paramount

importance.

The

patient

on

T h e s t a p e s a r c h i s r e m o v e d first, a n d t h e p r o s t h e s i s

a s s u m e d to have had a

is p l a c e d to e n s u r e correct length. Initially the pros-

cluding

thesis is held in a m a n n e r similar to a s t a p e s pros-

logic p r o b l e m s , and so o n ) .

!

Ad-

equate preoperative evaluation, a well-defined diag-

cardiovascular

the

operating

table

is

t h o r o u g h overall c h e c k (instatus,

allergies,

endocrino-

264

Surgery for Stapes Fixation

Surgery for Stapes Fixation

B

c

FIGURE 13-12.

FIGURE 13-13.

265

t • S u r g e r y for S t a p e s Fixation D y s g e u s i a following injury to the chorda t y m p a n i

b i m a n u a l l y a n d the

prosthesis shortened.

is characterized by tingling or a metallic taste on the

i m p o s s i b l e "or i n a d e q u a t e ,

tongue on

the operated

replaced.

rteplacement

improves,

but

vestibular

adhesions.

the

side,

reason

or both.

for

the

This always

improvement

is

the

Infection is rare, especially if a d e q u a t e prophylaxis

carries

the

Vertigo

risk

leading

persist

eventually require surgical correction.

obtained

(if

possible),

and

anti-

pulling sensory

but can occur up

(including meticulous cleansing of the ear canal) has cultures

of to

is be

t o t h r e e t o »ix y e a r s later. O n o c c a s i o n , v e r t i g o m i g h t

b e e n undertaken. If it occurs, the packing should be removed,

If this

prosthesis should

d e a f n e s s is rare after o n e m o n t h ,

unclear.

267

for

years,

even

with

good

hearing;

it

may

Patients usually have a mild sensation of echoing

biotics given (or c h a n g e d ) topically a n d parenterally.

along with

Infection

a n d a feeling of r e s o n a n c e m a y indicate fistulae or

may

lead

to

labyrinthitis

and

should

be

palsy

may

follow

injection

of

thetics, but should be only temporary. diately

following

damage

to

an

stapedectomy

exposed

during the procedure. dicated.

It

should

rare*

nerve;

nerve

the

anes-

Palsy i m m e -

probably

in

kept

in

mind

to local e d e m a

sectioning of the

Delayed

local

signals

oval

window

S u r g i c a l r e - e x p l o r a t i o n i s in-

be

probably is restricted of the

paralysis

must

that

damage

or puncturing

nerve is extremely

be

evaluated,

and

is

treated in the s a m e m a n n e r as Bell's palsy. Vertigo

is

fairly

common

postoperative

days;

however,

during

the

symptoms

first

few

should

be

ular sedatives. V e r t i g i n o u s s y m p t o m s s h o u l d not be left

lightly;

they could be a

unattended

deafness.

significance,

but tinnitus

might

Persistence

lead of

warning sign,

to

irreversible

vertigo

or

Reparative granuloma is o n e of the few e m e r g e n cies

following stapedectomy.

It occurs one to two

w e e k s after surgery and

is characterized by dimin-

ished

an

hearing

following

initial

gain.

Additional

s y m p t o m s include aural fullness, loss of discrimination,

and

disequilibrium.

The

tympanic

m a y be dull, red, a n d thickened, cular

flap

quadrant.

and

inflammation

in

membrane

with a hypervas-

the

posterosuperior

R e m o v a l of the granuloma

is d o n e in a

p i e c e m e a l fashion, a n d fascia is placed o v e r the graft.

mild, short lived, a n d r e s p o n s i v e to rest a n d vestibtaken

no

labyrinthitis, especially if a c c o m p a n i e d by vertigo.

treated aggressively. Facial

tinnitus of

severe

which

sensory vertigo

T h e prosthesis can be replaced by a n e w connective tissue

wire

prosthesis.

Granulomas

have

not

been

s h o w n to recur. Conductive

hearing

losses

occurring

after

initial

g a i n s are i n d i c a t i o n s for revision. A p r u d e n t w a i t i n g period

is

suggested.

A

perforated

tympanic

b r a n e will r e q u i r e a m y r i n g o p l a s t y .

mem-

A delayed con-

m i g h t be indicative of a p e r i l y m p h fistula, a thin or

ductive

leaky graft, p e r i p r o s t h e s i s leak a r o u n d a Teflon

pis-

b r a n e s u g g ists p r o b l e m s with t h e p r o s t h e s i s . I f t h e r e

ton (associated with fluctuating h e a r i n g loss), a pros-

are a d h e s i o n s a r o u n d the p r o s t h e s i s , t h e y s h o u l d b e

thesis

sharply

that

granuloma.

is

too

long,

labyrinthitis,

or

reparative

hearing loss with

excised

and

an intact t y m p a n i c m e m -

Gelfilm

or

Silastic

placed.

If

Operative causes include trauma during

n e c e s s a r y , the prosthesis is replaced. P r o s t h e s e s that

the operation or loose b o n e fragments in the vesti-

are d i s p l a c e d can be e i t h e r r e p o s i t i o n e d or r e p l a c e d ;

bule.

if the latter, t h e y are g e n t l y l o o s e n e d from the l o n g

Early

trauma

or

barotrauma

mnv

displace

a

p r o s t h e s i s , l e a d i n g to a fistula. If these s y m p t o m s persist

process of the incus with angled hooks bimanually.

in

spite of therapeutic

m e a s u r e s and clinical j u d g m e n t

suggests a compli-

If this is impossible, they can be s e c t i o n e d with small scissors a n d replaced. If necrosis of the long process

cation, or if there is a s e n s o r y hearing i n v o l v e m e n t ,

of the incus is present,

exploration is indicated. W h e n revising a stapedec-

the r e m n a n t . If this is i m p o s s i b l e , a malleus-to-oval

tomy

(or a n y ear p r o c e d u r e ) ,

w i n d o w p r o s t h e s i s ( o r p l a c e m e n t o f a b o n e graft o r

taken

in

lifting

a

thin

skin

important point might lead sary

tears

general, and

in

the

flap

or

special flap.

w i n d o w graft.

tissue The

is

round

this

to serious and unnecestympanic

not m u c h graft i s r e m o v e d

connective

care must be

Overlooking

placed window

membrane.

In

w h e n revising,

around

the

is evaluated

oval for

the prosthesis is placed in

T O R P ) is indicated. A piston is used if there is recurrent b o n e d e p o sition with c l o s u r e of the oval w i n d o w . If the focus is active a n d risk is i n v o l v e d ,

t h i n g s s h o u l d b e left

a s t h e y a r e for t h e t i m e b e i n g .

It should be kept in

mind

that

'.he

results

of revision

stapedectomy

are

tears; if it is q u e s t i o n a b l e , a s m a l l p i e c e of G e l f o a m

not so g o o d as in primary procedures; at the s a m e

can be used to obliterate the niche. If the prosthesis

time, vestibular involvement with secondary sensory

is found to be too long, the wire can be gently bent

hearing loss is m o r e likely.

I

268

S u r g e r y for S t a p e s F i x a t i o n

S u r g e r y for S t a p e s F i x a t i o n

269

Pertinent Histopathology FIGURE

13-15

This horizontal section s h o w s a large otosclerotic

of ( a c o b s o n ' s

nerve

on

focus fixing the s t a p e s a n t e r i o r l y a n d posteriorly. T h e

rows) a r e a l m o s t e n t i r e l y

stapes footplate is thickened. N o t e that the branches

bone.

the

promontory

(parallel

it-

s u r r o u n d e d by otosclerc'.ic

FIGURE

13-16

This section at the level of the oval w i n d o w area

footplate h a s b e e n e x c i s e d ; the site is evident. T h e

is from the temporal b o n e of an individual w h o had

vestibule is intact.

a successful stapedectomy.

vestibular contents.

1

Part of the otosclerotic

N o t e t h e close proximity of the

270

S u r g e r y for S t a p e s F i x a t i o n

S u r g e r y for S t a p e s F i x a t i o n

271

Cochlea

FIGURE This

13-17

section

individual

who

FIGURE 13-18 is

can

be

seen

the

underwent

piston prosthesis. it

from

a

temporal

bone

stapedectomy

of

an

with

a

T h e site of p l a c e m e n t is evident;

that

the

piston

was

too

deep

and

impinged on

the vestibular structures.

The surgicij

result w a s not ideal, a n d the patient had t w o piston ; placed subsequently

This

horizontal

otosclerosis and a caused

by

otitis

section shows a

stapes

middle ear cavity media.

The

section

fixed

by

with c h a n g e s shows

very

clearly that if the footplate w e r e r e m o v e d under these

conditions,

the

middle

ear

process

would

immedi-

ately penetrate the vestibule, with disastrous potential c o m p l i c a t i o n s . ( S o m e i n f l a m m a t i o n o f t h e v e s t i bule is evident.)

Fi Lasers in Otologic Surgery . Power density

CHAPTER 14

273

Power = Spot size

Lasers in Otologic Surgery T h e w o r d l a s e r i s a n a c r o n y m for light a m p l i f i c a -

T h e d e v e l o p m e n t of the laser in otologic surgery

tion by stimulated emission of radiation. In the early

has

2 0 t h century Albert Einstein predicted that this form

tool, h o w e v e r , it m u s t be used correctly. U n d e r s t a n d

o f e n e r g y e x i s t e d . I t w a s not until 1 9 6 0 that T h e o d o r e

ing

M a i m o n d e v e l o p e d t h e first w o r k i n g l a s e r , m a d e o f

training

a ruby crystal. Next, the gas laser was developed by

before one can

Alec Javon

tool.

come

the

in

1961.

many

From

advanced

these

early

lasers

have

models

in

medical

use

today.

been

a

the

remarkable

laser

is

advance;

absolutely

through

a

any

essential,

"hands-on"

efficiently

like

and

course

and

safely

is

prope-

use this

nev

t e r m s m u s t be d e f i n e d : power,

spot size,

anc

pulse duration. T h e p o w e r o f t h e b e a m i s i t s e n e r g y

for u s e i n t h e h e a d a n d n e c k a r e a . T h e a u t h o r s feel

o u t p u t a n d i s m e a s u r e d i n w a t t s . S p o t s i z e r e f e r s t'/

that the visible-wavelength lasers—the argon a n d the

the d i a m e t e r o f the b e a m , a n d c a n vary from microns

K T P - 5 3 2 — a r e b e s t s u i t e d for o t o l o g i c w o r k .

to millimeters. Pulse duration is the a m o u n t of timi

lasers

are

most

useful

for a n u m b e r of r e a s o n s : 1. T h e y

allow

fiberoptic cables. arms

are

intricate

needed spaces

for and of

energy

transmission no

delivery

the

in

which

the

function;

Therefore,

through

articulating, of

middle

the

ear

beam

is

bulky to

more

may

accomplished.

be

beam

actively

it m a y be m e a s u r e d continuous.

All

performs in

its

surgicc

m i l l i s e c o n d s or i

of these

functions can

b>

varied at a n y t i m e for different surgical n e e d s .

the

easily

Power

density

understood.

It

is

is

another concept defined

as

the

that

power

must per

bun:

v o l u m e (Fig. 1 4 - 1 / 1 ) . T h e p o w e r of the laser b e a m i

2. T h e visible-spectrum lasers do not need a car-

constant, but by varying the spot size of the b e a m a

FIGURE 14-1.

rier b e a m to be seen by the n a k e d eye. W i t h the C O ,

the focal point, t h e p o w e r d e n s i t y c a n b e s i g n i f i c a n t ! "

b e a m , w h i c h u s e s an invisible w a v e l e n g t h , a carrier

altered. Focusing the b e a m to a very small spot siz :

beam

in order to focus the b e a m on the

greatly increases the p o w e r d e n s i t y ; with a large spo*

s u r g i c a l s i t e ; i f t h e s e b e a m s a r e n o t exactly c o a x i a l , o r

size the p o w e r density is decreased. T h i s is a crucia'

is needed

r

if the mirrors of the articulating arm are imperfectly

c o n c e p t in laser s u r g e r y a n d is vital in u n d e r s t a n d s ; ,

aligned,

the surgical ramifications of the laser.

the

surgical

beam

may

not

be

delivered

precisely w h e r e it is n e e d e d . 3. The

visible-wavelength

T h e surgical b e a m s are readily

ab-

s o r b e d b y p i g m e n t a n d not b y c l e a r fluids, s o h e m o stasis can be accomplished. 4. Along

with

cutting,

and

tissue

tissue vaporization

spot

size

of

the

beam

and

varying

the

power.

Cutting of tissue requires the highest p o w e r density,

h a n d pieces have b e e n developed, allowing the b e a m

so a very small spot size and large a m o u n t s of p o w e r

to

are

delivered

by

an

alternate

a

effects of the laser b e a m are coagulation,

( F i g . 14— I S ) . T h e y c a n b e a c h i e v e d b y m a n i p u l a t i n g the

fiberoptic capability

tissue

n u m b e r of

be

COAGULATION Large spol Low power

necessar

A n u m b e r of laser systems are currently available

visible-wavelength

VAPORIZATION Large spol High power

In discussing the surgical applications of the laser three

These

CUTTING Small spol HiQh power

surgici!

method.

The

hand

used.

For vaporization of tissue,

full

power

i;

p i e c e is held like a scalpel, a n d the b e a m is focused

used with a larger spot size; the depth of vaporization

by moving it up and down.

can be controlled. Coagulation requires a large spot

size a n d a l o w p o w e r setting. Coagulation of vessels

site. Pulse duration a n d p o w e r are set on the m a c h i n e

can

visible-wavelength

itself or by a r e m o t e control at the operating table.

not

T h e b e a m is activated by a foot pedal.

only

lasers

be

(argon

accomplished and

KTP-532)

with and

with

the

C 0

2

laser. Actual

manipulation of the beam is d o n e by

the

surgeon. T h e spot size c a n be altered in two w a y s . With

Laser Stapedotomy

the b e a m delivery device attached directly to

the m i c r o s c o p e , the spot size is c h a n g e d by a rheostat-type

device

on

the

visualizing the beam,

microscope;

while

directly

t h e s u r g e o n c a n v a r y t h e di-

This section describes applications of the laser in the

middle

ear,

but

the

principles

and

techniques

ameter of the b e a m as n e e d e d . T h e hand-held deliv-

also apply to mastoid work. Specific approaches to

ery system

the surgical site (incisions,

focuses as

the hand

piece is m o v e d up

and d o w n while the b e a m is w a t c h e d at the surgical

flaps,

and

so on)

have

b e e n d e s c r i b e d e l s e w h e r e . T h e d i s c u s s i o n will focus

274

Lasers in Otologic Surgery

only

on

laser

applications

to

Lasers in Otologic Surgery

tissues;

any

The

specific

stapes

flap

is

rotated

anteriorly

until

thj

posterior border of the malleus is directly visualized

a p p r o a c h e s t h a t are c a l l e d for a r e e x p l a i n e d .

The

bony

scutum

is

then

removed

until

the

facial

nerve is visualized above the stapes and the pyramidal

Highlights

process

of

posteriorly.

It

the is

stapedial

tendon

very important

is

identified

to visualize

their

two structures to ensure adequate working room. Manipulation

1. G o o d local a n e s t h e s i a 2. Cood

done

hemostasis.

5. Superior

the

malleus

fixation

and

incus

is

thei.

of either structure as

th •

Attention

I •

n o w f o c u s e d o n t h e s t a p e s ; a g a i n , m a n i p u l a t i o n wiMi

nursing assistants

a small right-angled h o o k is d o n e to confirm fixation

instrumentation

T h e i n c u s - s t a p e s j o i n t i s s e p a r a t e d . T h e s t a p e s hold,?

6. U s e of a stapes holder.

is then b r o u g h t into the field.

7. Preservation of the chorda tympani.

With adjustment of the laser spot size and b e a -

8. Visualization of the p y r a m i d a l p r o c e s s a n d the

parameters

facial n e r v e .

done

preoperatively,

the

actual

lasei

work begins. T h e stapedial tendon is focused on a n c

9. Understanding of laser techniques and use. 10.

of

rule out

c a u s e of the c o n d u c t i v e h e a r i n g loss.

3. R e m o v a l of the s c u t u m . 4. Knowledgeable

to

vaporized, using the laser at 2.0 watts of p o w e r a r o

C o m p l e t e visualization of the ossicles.

a

pulsed

b e a m o f 0.;1

second.

T h e b e a m is sharp';

focused on the tendon by a " j o y stick" m o u n t e d cr t h e m i c r o s c o p e , a n d i s fired b y a foot c o n t r o l w h e n

Pitfalls

the

operator is

ready.

The

smoke

plume

is drawr

a w a y by a N o . 22 s u c t i o n tip h e l d in t h e o p e r a t o r ? left h a n d ( F i g . 1 4 - 2 A ) . 1. F o r m i n g

blebs

in

the

external

auditory

canal

while injecting

O n c e the tendon has been vaporized, a m e a s u r e m e n t i s t a k e n f r o m t h e l a t e r a l s u r f a c e o f t h e i n c u s ::•

2. Tearing the tympanic m e m b r a n e during elevation.

the

footplate of the stapes.

measurement

3. Inadequate

exposure.

4. Tearing the chorda

gives

Adding 0.5 mm to th s

the proper

length

t h e s i s . T h i s l e n g t h will v a r y w i t h

tympani.

for t h e

pro: -

the type of p r e -

thesis, point of m e a s u r e m e n t , a n d other factors. Th-'

5. Inexperienced scrub nurse.

laser b e a m

is then

6 . I n j u r i n g t h e facial n e r v e .

the stapes

Again, with a pulsed b e a m and (he sam •

7. Placing

the

prosthesis

too

deep

in

the

oval

window.

f o c u s e d on

the posterior crus t i

p o w e r settings, the crus is lased a w a y (Fig.

14-28).

T w o s u g g e s t i o n s m a y b e helpful a t this s t a g e : 1 . I f t h e h e m e i s v e r y w h i t e , v a p o r i z a t i o n m a y r>.» slow because the b e a m is absorbed

Procedure

help gre.itlv. ops. The

laser

stapedotomv

efficient procedure. draped done

in

the

under

bv pigment.

/.

d r o p o f b l o o d , b o n e c h a r , o r e v e n g e n t i a n violet will

usual

local

is

a

verv

successful

and

Initially the ear is p r e p a r e d and fashion.

All s t a p e d o t o m i e s are

anesthesia;

the

authors

use

2%

O n c e the

initial d a r k h o n v c h a r d e v e l

vaporization proceeds verv quicklv.

2. W h e n excess char builds up around

the b o n e

vaporization may again be slow. The char should bi gently chipped a w a y with a small right-angled pick O n c e the posterior crus has been is

addressed.

Often

it

can

be

th*

anterior

quadrant injection is m a d e with a 2 7 - g a u g e needle.

directly and r e m o v e d in the s a m e w a y as the poste

T h e ear is then

rior c r u s .

irrigated with povidone-iodine (Be-

crus

vaporized,

l i d o c a i n e with 1:20,000 e p i n e p h r i n e . A s t a n d a r d four-

W h e n the anterior crus cannot be directly

visualized because of the body of the Incus,

tadine) through a bulb syringe.

seei

a spe

round

cially d e s i g n e d m i r r o r is n e e d e d to reflect the b e a m

knife. A s e m i c i r c u l a r incision is m a d e starting at the

o n t o it. T h e b e a m i s f i r s t f o c u s e d o n t h e p r o m o n t o r v

6 o'clock

just

A

standard

stapes

position,

flap

is

traveling

elevated up

the

with

a

posterior canal

wall, and e n d i n g at the 12 o'clock position just above

anterior

introduced

to

until

the

anterior

crus.

The

mirror

the anterior crus is reflected.

is

The

t h e s h o r t p r o c e s s o f t h e m a l l e u s . T h e flap i s e l e v a t e d

b e a m is then b o u n c e d off the m i r r o r o n t o the anterio'"

to the a n n u l u s a n d the m i d d l e e a r is e n t e r e d in the

c r u s until it is v a p o r i z e d (Fig. 1 4 - 2 C ) .

usual fashion. T h e chorda t y m p a n i nerve is identified and

preserved

Attention

is

then

turned

to the

footplate of

the

stapes. T h e authors use either a 0 . 8 - m m or a 0 . 6 - m m FIGURE 14-2.

275

276

Lasers in O t o l o g i c S u r g e r y

o p e n i n g into

the

inner ear;

the

Lasers in Otologic Surgery

former is

preferred

Ossicles

unless there is not e n o u g h room. A template is placed on the footplate,

m a k i n g a visual i m a g e of the 0 . 8 -

m m site ( F i g . 1 4 - 2 D ) . T h e l a s e r i s t u r n e d t o 1.8 w a t t s and a 0.1-second pulsed beam.

A rosette pattern is

T h e laser has b e e n very beneficial in w o r k a r o u n d the ossicles. Since manipulation of the ossicles and

m a d e on the footplate, corresponding to the 0.8-mm

corresponding

stapedotomy opening.

rineural hearing loss and ossicular disarticulation,

the footplate.

Usually one

p u l s e will o p e n

It is important to overlap these laser

is

desirable

trauma to

potentially

minimize

this

may cause sensomanipulation.

i*

The

" h i t s , " b e c a u s e t h e c h a r f r o m e a c h p r e v i o u s hit will

highly focused b e a m of the laser can virtually elimi-

absorb

nate manual trauma involving the ossicles.

The

the

heat

template

and

is

allow

for

reintroduced

better to

vaporization

ensure

that

the

opening is the proper size. T h e prosthesis is then positioned over the incus

in

the presence of

cholesteatoma or adhesions around

T h e laser is especially useful

the stapes or ir

the oval w i n d o w niche.

a n d into the s t a p e d o t o m y o p e n i n g and c r i m p e d into

disarticulation

position (Fig. 14—2£). T h e part of t h e p r o s t h e s i s that

w a y s a hazard. U s i n g a finely f o c u s e d b e a m of short

fits i n t o t h e v e s t i b u l e i s e x a c t l y 1 m m i n l e n g t h ; w h e n

pulse duration (0.1 to 0.3 s e c o n d s ) a n d low p o w e r (i

p r o p e r l y p o s i t i o n e d , h a l f o f it, o r 0 . 5 m m , s i t s i n t h e

to 3 watts), disease can be vaporized without trauma

vestibule. S i n c e this section of t h e prosthesis is only

to the nearby ossicles.

1 mm long, it is easy to j u d g e the correct depth.

with

With very adherent disease

adhesions and

1. If s o m e of the laser hits do not c a u s e perilymph

for

the way

t h r o u g h the

or reducing and

through

the

bone,

the

prosthesis

will

easily break through the remaining ones 2. S o m e t i m e s from

a

small

amount

t h e v a p o r i z a t i o n i s left o n

of

the

the

crimped, All

sound

prosthesis

the in

tympanic the

is

at

material.

parameters,

Setting

surface

the b e a m

coagulation

of

faster

this

nuisance bleeding

procedure.

In

permits a

addition,

safer

vaporization

of

residual

char

o f the b e a m p a r a m e t e r s . A g a i n , this eliminates m u c h

footplate.

It is

of the vibratory trauma, reduces bleeding, and allows the surgeon to r e m o v e the a d h e s i o n s layer by layer

correctly

membrane

operating

is

the adhesions can be accomplished with adjustment

not n e c e s s a r y to r e m o v e this. Once

leak

these small vessels can be accomplished. Eliminating

the

go

polypoid

coagulation

f o o t p l a t e b o n e , t h i s i s n o t c a u s e for a l a r m . I f m o s t o f hits

perilymph

A n o t h e r u s e for t h e l a s e r i s i n t h e e a r filled w i t h

T w o additional suggestions are relevant here; t o f l o w a n d d o n o t e x t e n d all

resultant

suite

positioned is

and

repositioned.

(monitors,

fans,

(Fig. 1 4 — 3 8 ) . T h i s precision, e s p e c i a l l y in the d e p t h s of the oval w i n d o w with disease around the stapes greatly e n h a n c e s the ability to r e m o v e tissue w i t h o u

lasers, and so o n ) is reduced, and the patient is asked

trauma

to c o u n t n u m b e r s to obtain a subjective hearing level.

tures.

W h e n the s u r g e o n is satisfied with the hearing level,

to

the

surrounding

normal

anatomic

struc

A n o t h e r i d e a l s i t u a t i o n for L i - . l t w o r k i s e r o s i o r

the footplate is revisualized. If the p r o s t h e s i s is firmly

of

fixed in position, o n e or t w o small drops of autoge-

eroded

the

lenticular and

process

n o u s blood are instilled in the oval w i n d o w to act as

stapes,

the lenticular process often has e n o u g h bont

a seal. T h e flap is t h e n r e p o s i t i o n e d a n d p a c k e d with

left t o m a k e r e c o n s t r u c t i o n d i f f i c u l t .

G e l f o a m , a m a s t o i d dressing is placed, a n d the pa-

the surgeon can vaporize the b o n e quickly, sharply,

tient is taken to the recovery room.

a n d atraumatically to allow m o r e r o o m (or the recon-

lacking

a

of

bony

the

incus.

Although

connection

with

the

Using the laser

structive procedure (Fig. 1 4 - 3 / 1 ) . The

laser also is quite useful

in

tympanic mem-

brane work. Freshening the e d g e s of a perforation ir p r e p a r a t i o n for a graft c a n b e d o n e e a s i l y a n d q u i c k l y .

Laser Applications in the Middle Ear

A pulsed or continuous b e a m focused on the periplv ery of the

perforation

can

be

used

to

remove

thf

rolled e d g e s of the perforation (Fig. 1 4 - 3 C ) . W h e n elevation of the periosteum of the malleuc is required

Initially restricted to s t a p e d o t o m y p r o c e d u r e s , use of the laser has b e e n e x p a n d e d to include every case

the

umbo

in grafting techniques, is

pulling of this

always

very

the area around

adherent.

Tugging

and

tissue causes considerable vibratory

in the authors' otologic practice. It has proved to be

trauma

extremely useful in reconstruction and cholesteatoma

again, tissue can be lased a w a y without trauma (Fig

w o r k in the middle ear and mastoid.

14-3D).

throughout

the

ossicular

chain.

Once

FIGURE 14-3.

277

278

Lasers in Otologic Surgery

Lasers in Otologic Surgery

As m e n t i o n e d previously, the argon a n d KTP-532 lasers are readily a b s o r b e d by p i g m e n t a n d h e m o g l o bin.

Because

of

this

affinity,

hemostasis

of

Neurotology and the Laser |:

small

m i d d l e e a r cleft b l e e d i n g can often be a c c o m p l i s h e d .

T h e laser also is used extensively in neuroto!oj;ic

W i t h a large spot size, pulsed b e a m , a n d low power,

practice,

nuisance

be con-

a c o u s t i c n e u r o m a w o r k . It is u s e d for t h r e e f u n c t i o ; s:

A g a i n , the s p e e d a n d precision of the laser

(1) h e m o s t a s i s , (2) vaporization of the t u m o r , a n d i3)

trolled.

bleeding

from

mucosal

areas can

in h e m o s t a s i s lends itself greatly to the e n h a n c e m e n t

and

has

been

an

invaluable

addition, to

t u m o r c u t t i n g for r e m o v a l .

of reconstructive work. The

laser

is

ideally

suited

for

repair of a

fixed

m a l l e u s . T h e difficulty in drilling a r o u n d the ossicles

Procedure

In the attic is greatly reduced. Also, disarticulation of the incus-stapes joint is not n e e d e d b e c a u s e of the atraumatic bone vaporization.

A standard

postauric-

ular incision is m a d e a n d an a t t i c o t o m y is p e r f o r m e d (described e l s e w h e r e in this b o o k ) .

Drilling is d o n e

until the fixed o s s i c l e s are identified. In the a u t h o r s ' e x p e r i e n c e , the difficulty lies in freeing the fixation, which is usually anterior and medial to the malleus and incus.

I t i s e x t r e m e l y difficult t o drill this b o n e

a w a y ; c u r e t t i n g also i s c r u d e a n d difficult. O n c e the fixation is v i s u a l i z e d , the laser p r o v i d e s an ideal w a y to remove the bone without trauma

to the ossicles.

A pulsed or continuous b e a m sharply focused on the b o n y f i x a t i o n v a p o r i z e s t h e b o n e , a l l o w i n g free m o bility of the chain

(Fig.

14-3E).

A

small

piece of

Silastic is then inserted b e t w e e n the ossicles and the area of fixation to help prevent b o n e r e g r o w t h .

T u m o r exposure is accomplished by the standard approaches to the posterior and middle fossa, which have been described elsewhere. thine approach,

the internal

t h i n n e d o n its s u p e r i o r ,

posterior, and

is

inferior bor-

d e r s . O n c e t h e e g g s h e l l - t h i n b o n e i s left, t h e l a s e r j s used initially

for s u r f a c e c o a g u l a t i o n ( F i g .

14-4.").

T h e a r e a o v e r t h e facial n e r v e in t h e a n t e r o s u p e r i >r quadrant

is covered

with

Cottonoid

for

protection.

T h e laser is u s e d at a p p r o x i m a t e l y 4 to 6 w a t t s power

with

Because

a

of

pulsed

the

beam

beam's

and

affinity

a

large

for

spot

pigment,

if

sizr. it

is

absorbed by the hemoglobin. Coagulation is accomplished the

over

the surface of the

eggshell-thin

small

capillaries

bone.

tumor and

Surface

before

internal auditory canal

Summary

In the translabyrin-

auditory canal b o m

opening

through

coagulation the

dura

of

the

of

the

reduces and sometimes com-

pletely p r e v e n t s n u i s a n c e bleeding from small duril tumor vessels.

O n c e surface coagulation

is accom-

p l i s h e d , t h e facial n e r v e is identified in t h e i n t e r n i l The

laser

has

markedly

reduced

the

degree

of

auditory

canal.

Dissection

is

vibratory trauma to the ossicles and thus to the inner

c a n a l in the s t a n d a r d f a s h i o n .

ear

is identified a n d C o t t o n o i d

fluids.

By

minimizing

trauma,

the

surgeon

re-

jccomplished

in

is p a c k e d a r o u n d

it

duces the chances of iatrogenic sensorineural hearing

protection,

loss. T h e precision of the b e a m allows the surgeon

a w a y (Fig.

t o r e a c h a r e a s o f t h e m i d d l e e a r cleft s a f e l y , quickly,

tings and

and with

safely and quickly, often with m i n i m a l b l e e d i n g . '

less potential

for i n j u r y

to the patient.

A

s e c o n d m a j o r a d v a n t a g e lies in the h e m o s t a t i c prop-

the

After the facial ne ' e -dr

the tumor bulk in the canal is v a p o r L e c 14-4B). beam

Standard

By manipulating the p o w e r iet

spot size,

posterior

tumor can

fossa

be

vaporb ec

procedures—protect'jn

erties of the visible-spectrum laser. T h e confines of

of

the

m i d d l e e a r h a v e a l w a y s b e e n difficult to

brainstem with Cottonoid—are followed o n c e tun or

for

conventional

tive

properties

coagulation.

of the

The

reach

pigment-absorp-

visible-spectrum

beams

have

greatly e n h a n c e d this p r o c e d u r e . T h e s e two features

other

cranial

removal in

nerves,

the

cerebellum,

and

he

the a n g l e is b e g u n . T h e facial n e r v e is

a l w a y s kept in view but is protected with C o t t o n o . d T u m o r r e m o v a l b y v a p o r i z a t i o n i s d o n e a l m o s t e x c tt-

of the laser have added a n e w dimension to otologic

sively with

surgery.

The authors use

the laser in the cerebellopontine angle. full

p o w e r (8 to 10 watts) witt

a

FIGURE 14-4.

279

280

L a s e r s in O t o l o g i c S u r g e r y

continuous beam removal

is

and

done

a

from

medium the

spot

interior

size.

Tumor

protected with Cottonoid; the vestibular nerve is t h e t

the

tumor,

vaporized away.

of

In this c a s e ,

however,

the authora

initially k e e p i n g the c a p s u l e intact. S u c t i o n is used

feel t h a t c o n v e n t i o n a l s e c t i o n i n g w i t h s c i s s o r s is ju t

to draw a w a y the s m o k e p l u m e from the vaporization

as

sule collapses a n d further dissection of the capsule

icum

from

Small

surrounding

structures

With very large tumors, away

with

the

laser.

can

be

accomplished.

the t u m o r itself c a n be cut The

beam

parameters

are

tumors,

also can be debulked

with

the

lase:.

feeder vessels are easily coagulated with

th";

visible-spectrum beam. T h e capsule of the tumor cauterized

with

low

power

settings

and

a

;

diffused

c h a n g e d t o a v e r y s h a r p f o c u s w i t h full p o w e r a n d

beam. This use of the laser " t o u g h e n s " the capsule

c o n t i n u o u s duration. Using this b e a m , tumor bulk is

allowing

cut a w a y easily with m i n i m a l b l e e d i n g (Fig. 1 4 - 4 C ) .

tumor.

Large vessels cannot be coagulated with thr

beam,

but

T h e t e c h n i q u e s and u s e s of the laser in the suboccipital a p p r o a c h are similar. that

the

dura

over the

An additional step is

p o s t e r i o r lip

of the

for

easier

by

and

reducing

safer the

manipulation

feeder

vessels,

of

th'i

tumo •

removal is facilitated. In s u m m a r y ,

internal

the laser has proved to be an inva!

auditory canal is lased away; again, it can be removed

uable tool in otologic and n e u r o t o l o g i c w o r k . S t a m

quickly and without bleeding, and less time is needed

dard t e c h n i q u e s are greatly facilitated by the laser; if

for b i p o l a r c a u t e r y o r d r i l l i n g .

is

Sectioning of the vestibular nerve can also be done with

the

laser.

techniques,

and

The

nerve

is

isolated

the cochlear and

facial

by

standard

nerves are

CHAPTER 15

effective. Vascular lesions, especially small glomus t y m p a r -

p r o c e s s . A s its i n t e r i o r i s v a p o r i z e d , t h e t u m o r c a p -

precise,

probably

fast,

become

safe,

and

standard

very in

the

efficient, near

and

future.

wB Tht

next hurdle in otology is the inner ear, a n d the l a s » m a y be of benefit in the not too distant future.

Surgical Approach for Bone Conduction Hearing Devices B o n e conduction hearing devices are in an early

Aim

p h a s e o f d e v e l o p m e n t , b u t a first g e n e r a t i o n i s n o w available for clinical u s e . T h i s area o f o t o l o g y s h o u l d w i t n e s s significant positive c h a n g e s in future years. C o n d u c t o r s are neous the

and

available

in

transcutaneous.

surgical

two

This

types,

chapter

technique (Hough's

percutadescribes

technique)

for im-

T o e x p o s e i a site i n the area o f the linea t e m p o r a l i s for s a f e

placement

of the

receiver,

while

allowing

a d e q u a t e s k i n c o v e r a g e a n d a p o s i t i o n for t h e e x t e r n a l device that is comfortable and harmless.

plantation of the X o m e d audiant bone conductor. This

bone

c o n d u c t o r is

a

transcutaneous

device

consisting of an external and an internal c o m p o n e n t . Externally

(outside

the

patient),

a

microphone

re-

Procedure

ceives s o u n d and c h a n n e l s it to a s o u n d processor; this d i r e c t s an a m p l i f i e d signal a c r o s s the skin to the implant (the internal c o m p o n e n t ) ,

which is screwed

After preparation a n d s h a v i n g of the postauricular

into the skull. T h e amplified signal is transmitted by

area, the ear is sterilely d r a p e d . A postauricular line

skult vibration into the inner ear and

is traced h o r i z o n t a l l y at a level i m m e d i a t e l y superior

sound

is per-

ceived. T h e external and internal parts of the device are h e l d t o g e t h e r e l e c t r o m a g n e t i c a l l y . T h e s y s t e m is battery This

operated. device

to the tragus. T h e receiver (implant) is to be placed behind

the

mately 15

currently

is

used

in

patients

with

posterior to

template is

conduction

delineated (Fig,

benefit

from

congenital other

discrimination

conventional

hearing

who

aids

cannot

(owing

to

m a l f o r m a t i o n s , c h r o n i c external otitis or

factors).

expanded.

speech

Indications

for

the

device

will

be

edge

of

from

this

the

pinna.

positioned

and

Approxi-

posterior edge and

i m m e d i a t e l y a b o v e the horizontal line,

external or middle ear impairments with good bone and

18 mm

the bur hole

the site of the

receiver

15-24).

An incision site is traced at least 1 cm posterior to the edge of the receiver a n d injected with 2% caine (Xylocaine)

with 1:100,000 epinephrine.

lidoThe

S o m e b a s i c i n s t r u m e n t s ( X o m e d kit) are

i n c i s i o n is d e e p e n e d d o w n to t h e p e r i o s t e u m , a flap

required in order to position the internal receiver in

is e l e v a t e d , a n d the linea t e m p o r a l i s is identified. If

the skull; they are s h o w n in Figure 1 5 - 1 .

t h e s u b c u t a n e o u s t i s s u e s a r e t h i c k , t h e a r e a t h a t will

282

Surgical Approach for Bone Conduction Hearing Devices

Surgical Approach for Bone Conduction Hearing Devices

TIghtening tool

Universal wrenell handle

Full tap

Spanner attachment

Implant Guide cylinder

Deplh SlOp burs

Template

fiGURE 15-1

FIGURE 15-2.

283

S u r g i c a l A p p r o a c h for B o n e C o n d u c t i o n H e a r i n g D e v i c e s cover

the

adequate

receiver

is

thinned

in

order

transcutaneous transmission

to

and

permit

until t h e g a p b e t w e e n t h e w r e n c h h a n d l e a n d g u i d e

magnetic

c y l i n d e r i s c l o s e d . T h e full t a p i s t h e n r e m o v e d f r o m

coupling between the external and internal devices. The

area

where

reidentified, without

the

marked,

drilling

deep

receiver

will

and

evened

into

the

(This area needs depth

be

placed

with

bone

285

a

is

bur

(Fig.

kit

15-2B).

to receive the screw of the

implant.)

the s c r e w hole. T h e thread in the center hole is n o w r e a d y for t h e s c r e w o f t h e i m p l a n t . T h e full t a p i s r e m o v e d f r o m t h e u n i v e r s a l w r e n c h handle

and

replaced

with

the

spanner

attachment,

which is designed to hold the implant both mechanically a n d e l e c t r o m a g n e t i c a l l y . T h e i m p l a n t i s placed

U s i n g the larger bur in

t h e kit ( t h e b u r s h a v e a

in the spanner and inserted

through the guide cyl-

depth s t o p ) , the c e n t e r hole is drilled (Fig. 1 5 - 2 C ) . If

inder until it faces the center hole (Fig. 1 5 ^ 3 4 ) . T h e

a c e r e b r o s p i n a l fluid l e a k o c c u r s ,

implant

the site is sealed

with b o n e w a x a n d an adjacent site is used. Using the small

b u r in the set a n d

guide,

three

small

turned

the bur hole

control

holes

are

(with

the

screw

facing the

hole)

'/i-turn c o u n t e r c l o c k w i s e (again,

is

gently

in order not

to alter the thread in the hole), a n d then clockwise

template as

a

drilled (Fig.

1 5 - 2 D ) . T h e larger central hole is des-

cylinder is c l o s e d a n d there is a feeling of resistance

until t h e g a p b e t w e e n t h e w r e n c h

handle and guide

tined for t h e central s c r e w of t h e i m p l a n t . T h e three

(Fig. 1 5 - 3 B ) . T h e w r e n c h a n d the g u i d e c y l i n d e r are

a d j a c e n t control h o l e s will receive the three p e g s of

r e m o v e d . T h e i m p l a n t i s g e n t l y c h e c k e d for t i g h t n e s s

t h e g u i d e c y l i n d e r a n d i m p a r t s t a b i l i t y t o it.

(Fig. 1 5 - 3 C ) . T h e flap is r e p o s i t i o n e d , the i n c i s i o n is

T h e next step is to develop a thread in the center h o l e for t h e s c r e w of t h e i m p l a n t . T h i s is d o n e in t w o stages,

using

the

"half

tap"

and

"full

tap"

instruments. The

closed

in

layers

with

appropriate

sutures,

and

a

mastoid dressing is applied. Testing and use of the external device begins at 8 to 12 w e e k s , d e p e n d i n g u p o n the healing process.

guide

cylinder

is

placed

upright.

The

three

pegs are inserted in the corresponding three holes to keep the cylinder perpendicular to the b o n e surface. The

first

tightened

tap

to

to be

the

used

universal

is the

half tap;

wrench

this

handle with

the

tightening tool. T h e universal w r e n c h (with the half tap

tightened

cylinder

t o it)

and

is

rotated

then

slid

through

clockwise,

firmly

the guide pressing

This

is a

trauma; raising

the m a i n

handle and guide

The

half

loosened

tap

and

is

a

postauricular potential

fluid l e a k . removed

removed

from

from the

the

skull,

universal

then

wrench.

procedure

in

terms

be d o n e u n d e r local

of surgical

anesthesia and

has few complications. O t h e r than those inherent in

until

the gap b e t w e e n the wrench

simple

it can

a g a i n s t t h e s k u l l . R o t a t i o n c o n t i n u e s for % of a turn, cylinder is closed.

FIGURE 15-3.

Complications

is

flap

(discussed

elsewhere),

problem is that of cerebrospinal

B u r s with a " s t o p " (such as those in the

kit) do n o t a l l o w a d e e p p e n e t r a t i o n ; if a l e a k d o e s occur,

sealing the ;

opening

Prophylactic

with

bone

slid t h r o u g h t h e g u i d e c y l i n d e r , a n d p l a c e d o v e r t h e

these cases.

c e n t e r o f t h e s c r e w h o l e . F i r s t , i t i s g e n t l y t u r n e d '/2-

intravenous antibiotics is r e c o m m e n d e d . O t h e r comare

initial

t u r n c o u n t e r c l o c k w i s e (in o r d e r n o t t o a l t e r t h e t h r e a d

plications

previously m a d e by the half tap)*«nd t h e n c l o c k w i s e

surgical techniques.

caused

high by

dose

failure

be

should

suffice.

An

antibiotics could

wax

T h e full t a p i s n o w t i g h t e n e d t o t h e u n i v e r s a l w r e n c h ,

useful

in

of intraoperative to

follow

careful

287

Surgical A p p r o a c h e s for C o c h l e a r I m p l a n t s

CHAPTER 16

4. Removal of temporal muscle.

securing the electrode at this level with

5. D r i l l i n g of a s e a t for t h e i n t e r n a l r e c e i v e r .

sutures.

6. Simple mastoidectomy.

The

window

niche

is

visualized

through

7 . O p e n i n g o f t h e facial r e c e s s .

t h e facial r e c e s s ( F i g . 1 6 - 2 D ) . U s i n g a s m a l l b u r , t h e

8. Exposure of the round window.

a n t e r o s u p e r i o r lip o f t h e n i c h e i s r e m o v e d a n d

9. Placement of the internal receiver.

round

window

view.

If the

10. Insertion of the electrode via the round window

Surgical Approaches for Cochlear Implants

round

permanent

membrane

is

brought

directly

w i n d o w cannot be visualized,

the into

drilling

toward the p r o m o n t o r y will h e l p to p r o v i d e a straight

opening.

11. Securing of the internal receiver.

view of the basal turn, bypassing the " h o o k . " This

12. Closure, packing, and a mastoid dressing.

should be d o n e cautiously, in a step-by-step fashion. If b o n e

g r o w t h is

position"

p r e s e n t in

this area,

a

"straight

is reached a n d drilling is d o n e anteriorly

(forward) into the scala t y m p a n i . T h i s will lead to an

Procedure

o p e n s c a l a or p r o v i d e a s p a c e for p l a c i n g t h e e l e c trode.

i:

A

dummy

postauricular

electrode

is

position

of

used the

to

determine

internal

the

receiver.

It

should be at or a b o v e the linea temporalis, allowing enough

space

eyeglasses.

without

Some

interfering

surgeons

with

prefer

to

the

use

of

place

the

re-

ceiver m o r e inferiorly. T h e receiver site can be traced with a m a r k i n g p e n or a circular i m p r e s s i o n can be

The electrode

is

then

w i n d o w niche is sealed nonserrated should blunt

be

or used

wire

introduced

specially

coated

for e l e c t r o d e

guides

or

and

the

with fascia (Fig.

hoes.

alligator

insertion,

Extreme

round

16-3). helped

care

A

forceps must

by be

used w h e n handling the electrode in order to avoid damaging

it.

With

the

3M

House

type,

only

the

noninsulated portion is introduced.

left b y p r e s s i n g a d u m m y r e c e i v e r a g a i n s t t h e s k i n . A l t h o u g h there are m a r k e d differences a m o n g the different types of cochlear implants, ciples of and

the b a s i c prin-

s u r g i c a l a p p r o a c h e s for t h e s e d e v i c e s

detail.

As

in

the

facial

recess

approach,

a

larfe

Infiltration of the postauricular incision site is the

L

p o s t a u r i c u l a r flap i s e l e v a t e d i n c o n t i n u i t y w i t h t e

membrar?I

skin of the posterior canal a n d t y m p a n i c

same

as

in a

mastoidectomy;

directly exposing the middle ear cavity. A groove, s

sion.

T h e incision is

surgical a p p r o a c h e s that apply to implants in wide-

created

edge

of

spread

region of the round w i n d o w to the anterior margi i

the

of the

toward

Cochlear implants consist of an external

and

an

in

the

posterior canal,

extending

from

tte

mastoid cortex. T h e groove is covered with

it is m o r e

extensive b e c a u s e of the posterior e x t e n t of the inci-

are similar. T h i s c h a p t e r will d e s c r i b e o n l y the b a s i c use.

however,

the internal

level

of

it,

the

in

made

cm behind

receiver and

mastoid

order

1

to

outer

extends down

process avoid

the

without

to

bending

compromise

of

the

internal c o m p o n e n t . Externally, a m i c r o p h o n e picks

cortical b o n e a n d t e m p o r a l fascia o r with acrylic b o n e

occipital

up the s o u n d stimulation and sends it to the sound

cement,

b e t w e e n the scalp a n d the t e m p o r a l m u s c l e until the

processor,

the groove and contacting the electrode lead. Surgic? 1

stimulus

transforming

that

An internal

is carried

it

into

a

coded

to

the internal

electrical

component.

receiver c h a n n e l s this s t i m u l u s through

preparation and

purpose of stimulating the auditory

is

more

that

is the

artery.

The

flap

is

developed

spine of Henle is exposed.

similar

to

that flr

area

be

shavíl

portion of the temporal b o n e is r e m o v e d , as well as

a

regu'r

t e m p o r a l f a s c i a . T h i s a l l o w s for a n a d e q u a t e s e a t for

extensive

to

than

in

A

piece

of temporal

muscle over

the

squamous

the receiver, and

of cautery.

n e o u s d e v i c e is to be used.

away

field, t h e use o f c a u t e r y m i g h t lead t o t h e t r a n s m i -

receiver is drilled (Fig. 16—IB). It is i m p o r t a n t to do this in a p l a n e parallel to t h e s c a l p surface.

usually

placed

in

the

temporal

types of implant devices ground

if the latter,

require

it

is

muscle.

Different

sión

different

types of

potentially

electrodes.

The

internal

receiver can be

placed

either under

of

When

electrical

the electrodes are in the surgi'iil currents

into

devastating effects.

the

cochlea,

Judicious

use

through

the

round

surgical a p p r o a c h e s

window

of

the

cochlea.

Two

for p l a c e m e n t o f the e l e c t r o d e

it

receiver

W i t h a 2 - m m pilot drill,

with

permanent

1

A s e a t for* t h e i n t e r n a l

is

useful

sutures

to

(Fig.

(facial

recess);

(2)

the

mastoi-

sutures

are

passed

through

the

2-mm

holes

drilled a r o u n d the seat (Fig. 1 6 - 4 / 1 ) . F o r a percutaneous

plug,

an

opening

is

created

just

above

the

p l u g , a v o i d i n g s k i n t e n s i o n a t all c o s t s . T h e o p e n i n g is m a d e with a skin p u n c h of the s a m e size as the p l u g p r o v i d e d i n t h e m a n u f a c t u r e r ' s s u r g i c a l kit. T h e postauricular incision is closed with 3-0 abs o r b a b l e s u t u r e s for t h e s u b c u t a n e o u s t i s s u e s a n d 4 0 silk for t h e s k i n . A P e n r o s e drain c a n be u s e d . T h i s is followed by application of a m a s t o i d dressing.

Mastoidotomy/Tympanotomy Approach

With a

secure

the

16-2A,

8).

i

Advantages

two holes 2 mm apart are

Posterior Tympanotomy (Facial Recess)

to 0.75 cm from the outer edge; a passage b e t w e e n

1. T e c h n i c a l simplicity.

the holes is m a d e with a 0 . 5 - m m cutting b u r at a 3 0 -

2. Involves less b o n e drilling a n d tissue removal.

degree angle. For a percutaneous device, additional

3 . C a r r i e s a l m o s t n o r i s k t o t h e facial n e r v e .

h o l e s c a n b e drilled for p l a c e m e n t o f s c r e w s (Fig. 1 6 2/V).

T h r e e basic a p p r o a c h e s can be used: (1) the pos-

silk

drilled on both sides of the seat, at a distance of 0.5

will be d e s c r i b e d .

terior t y m p a n o t o m y

device,

the e l e c t r o d e s are in the surgical field.

protruding from the skin ( p e r c u t a n e o u s stimulation). the active electrode is placed on or

transcutaneous

for a t h i n n e r s c a l p if a t r a n s c u t a -

polar c a u t e r y , o r n o c a u t e r y a t all, i s i n d i c a t e d o n i ;

the skin ( t r a n s c u t a n e o u s stimulation) or with a plug In most cases,

wilt of ri-

the internal

anteriorly

mastoidectomy. An important point concerns the e » *

the active electrode;

"in-

prepared

positioning except

from dipping into

different" or g r o u n d electrode is placed close to or from

An

and

mastoidectomy,

o n e o r m o r e a c t i v e e l e c t r o d e s t o the c o c h l e a , for t h e nerve.

in order to prevent skin

O n c e the electrode has b e e n placed,

receiver is secured. For a t r a n s c u t a n e o u s device, 4-0

Surgical Steps

d o t o m y / t y m p a n o t o m y ; a n d (3) the external auditory

4 . A l l o w ; for direct v i e w o f a n d w o r k i n t h e r o u n d window

A s i m p l e m a s t o i d e c t o m y a n d o p e n i n g o f t h e facial recess is d o n e (Fig. 1 6 - 1 A ) (see C h a p t e r 7 ) ; the only

tissue

difference

ously).

is

that

the

edges

of

the

cavity

are

not

groove

for

niches.

5. A c t i v e electrode is c o v e r e d by a thick layer of along

its

entire

course

(not

just

subcutane-

' c a n a l g r o o v e . T h e a p p r o a c h via t h e e x t e r n a l a u d i t o r y

1. Positioning of the internal receiver site.

saucerized

the

6. P r o v i d e s a better a n g l e in the basal turn of the

i canal

2. Postauricular incision.

electrode. T w o additional holes c a n be drilled in the

c o c h l e a for s l i d i n g t h e e l e c t r o d e , m a k i n g full i n s e r t i o n

3. E l e v a t i o n of a p o s t a u r i c u l a r flap.

border

easier.

I San

groove has been used Francisco devices;

for s o m e o f t h e S t o r z -

it will

not be d e s c r i b e d

in

of

in the

order

to

mastoid

allow cavity

for for

a

the

purpose

of

288

Surgical Approaches for Cochlear Implants Surgical Approaches for Cochlear Implants

Internal receiver seat

B

Round window niche

FIGURE 16-1. FIGURE 16-2

289

Surgical

Approaches

for C o c h l e a r

Implants

S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s

Internal receiver 1

FIGURE l ( M FIGURE 1 6 - 3

291

292

S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s

7. S m a l l p o s t a u r i c u l a r flap c a r r i e s less risk of h e -

S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s small

bur

and

the

round

window

m a t o m a or infection; requires no drains; m a k e s heal-

brought directly into view (Fig.

ing easier;

tional

and

percutaneous

allows

no tension

of the

skin

with

plugs.

drilling n e e d e d

8. Allows faster recovery and shorter hospitaliza-

piece of G e l f o a m

is

used

to c o v e r the round

window and a

large piece of cotton

the

This

ear

canal.

A

mastoidotomy

mastoidea opening

1. E n d a u r a l i n c i s i o n s ( L e m p e r t 1 a n d II).

is placed over

avoids contamination

by

bone

is d o n e by drilling in t h e fossa

toward

should

the

be

antrum

large

(Fig.

enough

16-5D).

to

The

visualize

the

a n t r u m . T h e p o s t e r i o r e d g e i s b e v e l e d a n d all s h a r p

2. C a n a l i n c i s i o n s at 6 a n d 2 o ' c l o c k .

bony e d g e s are s m o o t h e d . T h e incus is disarticulated

3. Exposure of the middle ear. 4.. Drilling of the r o u n d w i n d o w niche a n d visalization of the round w i n d o w m e m b r a n e .

from its s t a p e s a n d m a l l e u s a t t a c h m e n t s w i t h a j o i n t knife

and

totally

removed.

If

desired,

a

dummy

electrode can be inserted through the m a s t o i d o t o m y

5. Small atticotomy.

o p e n i n g and into the niche to verify the a d e q u a c y of

Mastoidotomy.

the exposure. T h e middle ear a n d

7. Postauricular incision. 8. Removal of temporal muscle and periosteum s e a t for t h e i n t e r n a l r e c e i v e r .

1 0 . T u n n e l i n g of the e l e c t r o d e from the postauricular incision into the m a s t o i d o t o m y o p e n i n g 11. Introduction of the electrode into the a n t r u m and

until

dust a n d debris from the m a s t o i d o t o m y drilling.

Surgical Steps

a

is delayed

[Facial Recess] A p p r o a c h ) . A

9. Drilling of

for e x p o s u r e

is

A n y addi-

the electrode is inserted (see Posterior T y m p a n o t o m y

tion

6.

membrane

16-5C).

middle ear

mastoid are then

filled w i t h a n a n t i b i o t i c s o l u t i o n . A

postauricular

incision

is

needed

for

the

sole

purpose of placing the internal receiver; it should be made

at

enough

or

above

space

the

without

linea

temporalis,

interfering

with

allowing

the

use

of

e y e g l a s s e s . Lidocaine ( X y l o c a i n e ) 2% with 1:100,000 e p i n e p h r i n e is injected. T h e circumferential incision

12. Insertion of the electrode into the cochlea.

m e a s u r e s 3 to 3.5 cm and is d e e p e n e d

13. S e c u r i n g of the internal receiver. 14. C r e a t i o n of a skin o p e n i n g (for p e r c u t a n e o u s receivers).

subcutaneous

tissues

until

the

t h r o u g h the

temporal

muscle

is

r e a c h e d ( F i g . 1 6 - 5 E , F). T h e s e a t s i z e f o r t h e i n t e r n a l receiver is m e a s u r e d , and the corresponding under-

15. Closure, packing, and a mastoid dressing.

lying temporal m u s c l e a n d p e r i o s t e u m are r e m o v e d . T h e p e r i o s t e u m i s s a v e d for g r a f t i n g t h e r o u n d wind o w niche. T h e b o n e seat is drilled d o w n to accom-

Procedure

modate

the

receiver

(Fig.

16-6/1)

and,

depending

u p o n the type of receiver, a d d i t i o n a l Iw4es are drilled e i t h e r for s u t u r e s o r for s c r e w p l a c e m e n t ( s e e P o s t e T h e first i n c i s i o n ( L e m p e r t I ) i s m a d e s e m i c i r c u m -

rior T y m p a n o t o m y [Facial R e c e s s ] A p p r o a c h ) .

ferentially b e t w e e n 6 and 12 o'clock on the posterior

An electrode guide is passed from the endaural to

wall at the b o n y cartilaginous junction. T h e second

the postauricular incision bv t u n n e l i n g it b e n e a t h the

incision

(Lempert

II)

runs

between

the

tragus and

temporal muscle.

An electrode guide, which is sim-

h e l i x (at t h e i n c i s u r a ) . T h e e x t e n s i o n o f t h i s i n c i s i o n

ilar t o a n a n t r u m t r o c a r , i s s p e c i a l l y c u r v e d a n d h a s

is approximately 0.75 cm.

a

(cartilaginous portion)

The

posterior canal skin

blunt

distal

opening

to avoid

d a m a g i n g the elec-

is p r e s e r v e d a n d g e n t l y ele-

t r o d e (Fig. 1 6 - 6 8 ) . T h e o b t u r a t o r i s r e m o v e d a n d the

vated with a small periosteal elevator, clearly expos-

e l e c t r o d e i n t r o d u c e d into the g u i d e (Fig. 1 6 - 6 C ) ; the

ing the entire posterior b o n y canal (Fig. 1 6 - 5 / 1 ) . T w o -

guide is then withdrawn and,

prong retractors are used

is carried into the m a s t o i d o t o m y o p e n i n g . It is then

three-prong

for e x p o s u r e ; o c c a s i o n a l l y

retractors are needed.

passed

W i t h a scalpel, vertical incisions are m a d e at 6 a n d

to the a n t r u m and

exposed

w i t h it,

the electrode

into the middle ear.

The

round w i n d o w m e m b r a n e is detached with

2 o ' c l o c k . In a c o m p l e t e l y d r y field, a flap is e l e v a t e d

an a n g l e d pick, and the electrode is introduced with

and

a

the

annulus.

middle

ear

cavity

is

entered

beneath

the

All a n a t o m i c s t r u c t u r e s a n d l a n d m a r k s a r e

visualized.

Using stapes curets,

the posterior canal

nonserrated

baby

pointing toward

alligator

the basal

mediately past the h o o k (Fig.

wall is e n l a r g e d and a small a t t i c o t o m y is d o n e (Fig.

of

1 6 - 5 8 ) . Special attention is paid to the round w i n d o w

wrapped

niche. T h e anterosuperior portion is removed with a

pieces

the

round of

window

around

the

Celfoam

is

of

then

in

an

angle

the cochlea,

im-

16-6D). The opening

sealed

electrode are

forceps

turn

with

periosteum

(Fig.

16-7A).

placed

lateral

Small to

the

FIGURE 16-5

293

294

Surglcal Approaches for Cochlear Implants

Surgical Approaches for Cochlear Implants

Ground electrode

A

FIGURE 1&--7

295

296

S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s

p e r i o s t e u m graft.

With a S y m b i o n implant,

the pro-

plug is

made anterior

to

the

periauricular incision

m o n t o r y electrode is positioned over the p r o m o n t o r y

with a skin p u n c h of the s a m e s i z e as the plug (Fig.

and secured

1 6 - 7 C ) . Skin tension should be avoided.

w i t h a c o v e r i n g of p e r i o s t e u m graft as

well.

T h e canal

T h e internal receiver is then s e c u r e d in place with sutures o r s c r e w s (Fig.

1 6 - 7 B ) , the ground electrode

flap

is

repositioned.

Gelfoam and

of the canal,

and

gauze

is e m b e d d e d

in antibiotic

(if s e p a r a t e ) is p l a c e d in t h e t e m p o r a l m u s c l e fibers,

o i n t m e n t in the distal o n e third. Incisions are closed

and

with

the

antrum.

rest of the If a

periosteum

percutaneous

is

used

plug is being

t o seal, t h e used,

im-

p e d a n c e i s c h e c k e d a t t h i s p o i n t . A n o p e n i n g for t h e

CHAPTER 17

an

antibiotic o i n t m e n t are used in the distal t w o thirds

s u b c u t a n e o u s 3-0 c h r o m i c catgut and

skin su-

tures of 4-0 silk (Fig. 1 6 - 7 D ) , a n d a m a s t o i d dressing is a p p l i e d .

Surgery for ; Incapacitating Peripheral Vertigo The

title o f this c h a p t e r h a s b e e n

lected

to

indicate

that

the

surgical

purposely seprocedures

Endolymphatic Sac Procedures

de-

scribed h e r e a r e d e s i g n e d for t r e a t m e n t o f v e r t i g o o f labyrinthine origin.

At the s a m e time,

the term "in-

These procedures constitute a conservative,

usu-

c a p a c i t a t i n g " i m p l i e s t h a t s y m p t o m s a r e still p r e s e n t

a l l y e f f i c i e n t a p p r o a c h for v e r t i g o , a n d a r e t h e initial

after a d e q u a t e m e d i c a l e v a l u a t i o n a n d

It

choice (not u n c o m m o n l y the only choice necessary)

procedures are

of m a n y surgeons. Despite the location of the sac in

is understood,

therefore,

that

these

treatment.

performed in a small p e r c e n t a g e of patients, since in

the posterior fossa dura,

the m a j o r i t y o f c a s e s

and

adequate

safe

operation.

suffice.

(Evaluation

m e d i c a l t r e a t m e n t a l o n e will

and

medical

treatment are out-

side the s c o p e of this b o o k . ) In a d d i t i o n ,

it should

surgical In

the

k n o w l e d g e o f its a n a t o m y

technique event

usually

of

failure,

permit any

a

other

p r o c e d u r e can be d o n e w i t h o u t a d d e d difficulty

be kept in m i n d that vertigo is a m a n i f e s t a t i o n of an underlying

problem

that

must

be

assessed

and

(if

possible) defined; d e p e n d i n g on the c a u s e , different surgical a l t e r n a t i v e s will b e s e l e c t e d . T h i s i s o n e o f

Aim

the a r e a s i n o t o l o g y w h e r e o u r l a c k o f t r u e k n o w l e d g e is most evident; therefore, careful and nondestructive c h o i c e s a r e r e c o m m e n d e d i f a t all p o s s i b l e . Surgical procedures can be destructive or conser-

To

identify

overlying

the

and

expose

dura

mater

the of

endolymphatic

the

posterior

sac

cranial

fossa.

vative i n n a t u r e . T h e y m a y b e a i m e d a t d r a i n i n g a n assumed

endolymphatic

hydrops,

whether

at

the

endolymphatic sac level or at the saccule, they m a y involve

destruction

tomy) and/or other

nerves,

of

sectioning such

as

the

labyrinth

of

the

the

singular

posterior semicircular canal.

(labyrinthec-

vestibular

nerve

nerve

of

the

N o n e of the m a n y sur-

gical p r o c e d u r e s a v a i l a b l e a r e u n i v e r s a l l y a c c e p t e d o r provide

1009c

relief.

T h e s e are

factors

to

keep

in

mind w h e n selecting a specific approach. This chapter

will

most

describe

commonly,

those

that

without

are

used

implying

described are useless or unimportant.

or

that

discussed those

Highlights and Surgical Steps

or

not

1. P e r f o r m a c o m p l e t e s i m p l e m a s t o i d e c t o m y . 2. Drill to, b u t not b e l o w ,

the d o m e of the hori-

zontal semicircular canal. 3. Identify,

preserve, and measure the hard angle

c o n t a i n i n g the posterior semicircular canal. 4. Identify the position of the sigmoid its r e l a t i o n s h i p t o T r a u t m a n n ' s t r i a n g l e .

sinus and

298

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

I.

Decompress

the lateral

sinus and

dissect

the

6.

tends to partially c o v e r the dura or m a k e a c c e s s to it difficult,

i n f r a l a b y r i n l h i n e cell tract.

the

patient's

position

should

be

checked

first; t h e h e a d m i g h t b e b e n t t o o far f o r w a r d . I f a f t e r

Incise the e n d o l y m p h a t i c sac.

r e p o s i t i o n i n g t h e h e a d o f t h e p a t i e n t t h e s i n u s i s still prominent,

it should be d e c o m p r e s s e d by removing

part o f its b o n y c o v e r i n g l a c i n g t h e d u r a ,

Pitfalls

infralaby-

rinthine cells m a y h a v e to be drilled (leading toward, the jugular bulb). T h e sac is identified. At this point, there are several alternatives:

1. S k e l e t o n i z i n g or d a m a g i n g the posterior semicircular canal. 3. Failing

to identify

1. D e c o m p r e s s i o n of the sac (removal of the b o n y c o v e r i n g ) i s all t h a t i s d o n e .

2. Insufficiently unroofing the dural plate. the e n d o l y m p h a t i c sac and

its l u m e n .

2 . T h e s a c i s i n c i s e d i n its l a t e r a l s u r f a c e w i t h a s h a r p knife (for e x a m p l e , a sickle knife). T h i s is the o r i g i n a l ( a n d c u r r e n t ) P o r t m a n n p r o c e d u r e ( F i g . 17-

4. D a m a g i n g the incus.

2C).

5. Debris in the middle ear.

3 . A v a l v e i s p l a c e d i n t h e l u m e n (in t h e e x p e c t a -

6. B l e e d i n g in the lateral sinus,

tion

that

microliters

of

excessive

endolymph

wiF

drain). 4. A small incision is m a d e on the medial surface

Procedure

of

the

sac

space.

inserted. In e n d o l y m p h a t i c sac surgery, a thorough simple

in

Into

order

this

to

open

opening

a

up

the

flanged

subarachnoid

Teflon

tube

is

The o u t e r s u r f a c e is tightly p a c k e d (a p i e c e

of fascia can be u s e d ) .

mastoidectomy (see Chapter 7) is advocated. During

5. A thin piece of Silastic s h e e t i n g (0.01 c m ) is cut

this step the b o n y plate o v e r l y i n g the posterior cra-

in a T - s h a p e d fashion a n d placed in the l u m e n . S m a l l

nial f o s s a d u r a i s i d e n t i f i e d . T r a u t m a n n ' s t r i a n g l e i s

pieces of Silastic s h e e t i n g (spacers) are used to sep-

defined and

arate the dura from the floor of the posterior canal.

the hard b o n e containing the poslerior

semicircular cana!

is identified

(Fig.

\7-\A.

H).

The

s a c c o m e s toward the dura from the direction of (he

A Silastic " a p r o n " is applied a n d held in place with C-elfoam (Fig.

it

exits

(he

hard

angle

intact.

A

good

method

of

17-3/1-D).

1 lie m a s t o i d c a v i t y i s p a c k e d w i t h G e l t o a m o v e i

posterior semicircular canal and can be identified as

the d e c o m p r e s s e d a r e a , and the incision is c l o s e d in

preventing d a m a g e to the posterior semicircular canal

lavers

i s t o m e a s u r e t h e a r e a c o n t a i n i n g t h i s s t r u c t u r e ,uul

procedure,

l e a v e it u n t o u c h e d ( u n d r i l l e d ) . W i t h a l e n e s t r o n i e t e r ,

t v m p a n i c m e m b r a n e (Fig.

measure

t h o r o u g h l y c l e a n s e the m a s t o i d c a \

the

H I m m f r o m t h e tip o f t h e s h o r t p r o c e s s o t

incus

or

horizontal

fossa

incudis,

along

semicircular canal

[he

a\is

(30 d e g r e e s

ol

[he

from

the

with

a p p r o p r i a t e Mitures. a ventilation

the end

of

the

ho p l a c e d

in

the

At

tube m a \

11

I7--3/ V 1

is i m p o r t a n t to h e I ore c l o s u r e .

'

I h e e f f e c t i v e n e s s of this p r o c e d u r e m a v he d u e to decompression

ol

oveilving

hone,

drainage

of

en

l e g m e n ) ; t h e n m e a s u r e 12 mm from Ihe loss.i i m u d i s

d o l v m p h b v o p e n i n g o l I h e sac, i n c r e a s e d v a s c u l a r -

at an angle ot

i t y , o r o t h e r l a c l o r s , , i d i s i u s s i o n i s o u t s i d e the s c o p e

IS d e g r e e s k o n i the l e g m e n l l i g .

17

\H). T h i s a r e . i i s lett u n t o u c h e d w h i l e ( h e i n l r a l . i l n -

nl

r i n t h i n e cell tract is drilled In e x p o s e the s a c location

that i n v o h e s o p e n i n g t h e s a c h a s c o m p a r a b l e r e s u l t s .

(Fig.

C).

\7-\H.

Special

attention

is

paid

to

the

this book.

Ihe

Complications

are

remains

those

of

(he dural

plate,

reducing

triangle (interestingly,

this

merit is

prevention.

posterior

(see

c a n a l , a n d c e r e b r o s p i n a l fluid f i s t u l a e . T h e b e s t treat- '

Trautmann's

the

mastoidectomy

sion,

partially overlies

of

procedure'

Chapter

it

opening

that a n v

position of (lie s i g m o i d s i n u s (Fig. 1 7 - 2 / 1 ) ; on o c c a the size of

7),

lad

semicircular

T h e technique of isolating the

i s fairly c o m m o n i n p a t i e n t s w i t h M e n i e r e ' s d i s e a s e ) .

hard angle is practical. If the posterior semicircular

The

plate

canal

then

gently elevated and separated

is

thinned

down

to

eggshell from

thickness, the

under-

is accidentally o p e n e d ,

lying d u r a with a duckbill elevator. T h e sac is iden-

certain.

tifiable as a t h i c k e n e d w h i t e area

uncommon

t h e thin s u r r o u n d i n g dura (Fig.

o f t h e d u r a ewer

I 7 - 2 R ) . T h e posterior

semicircular canal s h o u l d not be t h i n n e d or skeletonized.

Drilling

is

done

immediately

inferior

to

this

a r e a . If t h e lateral s i n u s is in s u c h a p o s i t i o n that it

the

fistula

should

be

grafted i m m e d i a t e l y ; h o w e v e r , a " d e a d e a r " is a l m o s t

should

Fistulae and

be used

uncommon

that

leak

cerebrospinal

self-limiting;

high-dose

in o r d e r to a v o i d

fluid

meningitis.

to h a v e to re-explore and

are

antibiotics

place a

It is large

piece of fascia a n d m u s c l e ( a l o n g with tight p a c k i n g of the mastoid eavitv with C e l f o a m ) .

FIGURE 17-1

300

Surgery for Inc~pacitaling Peripheral Ver";;n

Surgery for Incapacitating Peripheral Vertigo

Apron 0.01 ern Silastic

T-strut IOserted

E IICUgl: 17-2. HCUgE 17-}

301

302

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

Saccule Procedures

a t t e m p t i n g this p r o c e d u r e ,

a

reasonable

n u m b e r of

temporal b o n e dissections are r e c o m m e n d e d . Destruction T h e s e a r e m e n t i o n e d for t h e s a k e o f c o m p l e t e n e s s and an overall concept. T h e most c o m m o n (such as the

Fick and

severe, are

tack

procedures)

irreversible

rarely

used.

are

sensorineural

(An

associated hearing

intermediate,

loss

with and

safer alternative

of

the

posterior

labyrinth

by

ultra-

sound

(Arslan's p r o c e d u r e ) is not described in

book.

Its i n d i c a t i o n s a r e f e w a n d c a n b e c o v e r e d b y

the

other

procedures;

furthermore,

the

author

this has

n o e x p e r i e n c e w i t h it. T h e r e a d e r i s r e f e r r e d t o t h e

Incus

literature.

used occasionally in cases of otosclerosis associated flfcith h y d r o p s is a wire c o n n e c t i v e tissue prosthesis with a small peg [from the wire a r o u n d the c o n n e c tive tissue] [Fig. 1 7 - 4 4 ) ; this is d e s c r i b e d in C h a p t e r

Labyrinthectomy

13.) Both procedures are intended to d e c o m p r e s s a dilated s a c c u l e u n d e r the a n t e r i o r portion of the oval window, through

which a

is clearly

transcanal

exposed.

approach.

T h e v are

done

T h e Fick operation

involves o p e n i n g the footplate and then the saccule (Fig.

17-4C),

whereas

the

tack

procedure involves

the p l a c e m e n t of a sharp tack through the footplate ( a n t e r i o r a s p e c t ) ( F i g . 1 7 - 4 8 ) . It is i m p o r t a n t to seal the

footplate with connective

Icom presses"

the

saccule

tissue.

when

it

The

tack

"de-

b e c o m e s dilated.

Labyrinthectomy, a monly

employed,

labyrinth. usable

p r o c e d u r e that is fairly c o m -

entails

total

destruction

of

hearing;

even

then,

the

significance

of

the

p r o c e d u r e m u s t be c o n s i d e r e d . Is the causative disease bilateral? C o u l d it eventually b e c o m e bilateral? Is t h e r e a n y c h a n c e that the patient n e e d s a c o c h l e a r implant? A l a b y r i n t h e c t o m y c a n be d o n e t h r o u g h a

C l o s u r e is s i m i l a r to t h a t for a s t a p e d e c t o m y .

the

It s h o u l d be r e s e r v e d for p a t i e n t s w i t h no

trans-

canal or a t r a n s m a s t o i d a p p r o a c h .

Singular Neurectomy Transcanal

Approach

1 his selectively destructive p r o c e d u r e entails sec-

Highlights

tioning the n e r v e of the posterior semicircular canal (.singular n e r v e )

for t h e t r e a t m e n t o f b e n i g n

periph-

eral positional v e r t i g o ( c a u s e d by an alteration in the

1. C l e a r i d e n t i f i c a t i o n of t h e facial n e r v e is e s s e n -

fflpsterior semicircular canal, such as cupulolithiasis).

tial

T h e nerve r u n s parallel to the a n t e r o s u p e r i o r portion

the oval

of the round w i n d o w m e m b r a n e (Fig. ft T h e round canal

17-5/1).

w i n d o w n i c h e i s e x p o s e d via a

approach.

If

necessary,

(he

to avoid a n y potential lesions

hile drilling in

window.

2. R e m o v a l of the oval w i n d o w c o n t e n t s m u s t be trans-

posteroinferior

done without d e e p e n i n g the w i n d o w or pushing the instrument

hard

into

the

walls.

Only

a

thin

plate

c a n a l w a l l i s c u r e t t e d for b e t t e r e x p o s u r e . T h e b o n v

s e p a r a t e s this area

r o u n d w i n d o w n i c h e is drilled carefully with a small

a n d a c e r e b r o s p i n a l fluid leak is a p o t e n t i a l c o m p l i -

bur

cation.

and

the

anterosuperior

portion

of

the

round

w i n d o w m e m b r a n e i s e x p o s e d (Fig. 17-5H). T h e b o n e Htmcdiately

anterior

to

the

membrane

is

thinned

from

the internal auditory canal,

E x p o s u r e i s o b t a i n e d via a n e x p l o r a t o r y t y m p a n otomy approach (see Chapter 5).

Both the oval and

d o w n (without involving the m e m b r a n e and leaving

the r o u n d

It is i m p o r t a n t to

a

the m e m b r a n e and

visualize and identify the position and status of the

1.5 t o 2 m m d e e p

facial n e r v e i n r e l a t i o n s h i p t o t h e o v a l w i n d o w ( F i g .

piece of b o n e

the thinned

intact

area).

The

between nerve is

(slightly d e e p e r is the basal turn of the c o c h l e a ) ; it is •rentified

and

sectioned

with an angled

h o o k (Fig.

p—5C), and the area is covered with Gelfoam. I

T h i s p r o c e d u r e is m o r e e a s i l y d e s c r i b e d t h a n per-

w i n d o w s are exposed.

1 7 - 6 ) . T h e stapes is r e m o v e d a n d the c o n t e n t s of the oval w i n d o w a r e s u c t i o n e d . W i t h a h o o k , the rest of the c o n t e n t s are r e m o v e d (Fig.

f o r m e d . It is q u i t e difficult to find t h e n e r v e { e v e n in

(Fig.

a

saturated with

temporal

bone

in

the

laboratory).

For

anybody

1 7 - 7 / 1 , B). T h e p r o -

m o n t o r y is drilled a n d both w i n d o w s are c o n n e c t e d 17-7C).

The

labyrinth is filled

with G e l f o a m

streptomycin sulfate. Text

continued

on

page

307

FIGURE

V-4

303

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

FIGURE 17-6.

307

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

Transmastoid Approach (Transmastoid Labyrinthine Dissection)

4. Bone

must

be

completely

sinodural angle and 5. A

dural

flap

removed

from

the

posterior fossa. is

hinged

anteriorly

and

draped

nerve

is sec-

over the posterior semicircular canal. 6. T h e superior half of the eighth tioned.

Aim C o m p l e t e removal of the semicircular canals and

Pitfalls

the soft t i s s u e o f t h e v e s t i b u l e

Highlights

1. Failing

to

remove

bone adequately

up

to

the

posterior semicircular canal. 1. T h e

sinodural

angle

must

be

completely

2. Inadvertently entering the labyrinth.

thinned for a d e q u a t e e x p o s u r e o f the vestibule.

3. Failing to d e c o m p r e s s the sigmoid sinus ade-

2 . T h e t e g m e n m u s t b e t h i n n e d for a d e q u a t e vis-

quately, leading t3 poor visualization.

ualization of the superior aspect of the semicircular

4. Incompletely sectioning the vestibular nerve.

canals.

5. Inadvertently sectioning the cochlear nerve fi-

A simple m a s t o i d e c t o m y is done. T h e three semi-

bers.

circular c a n a l s are s k e l e t o n i z e d until t h e m e m b r a n o u s labyrinth is visible t h r o u g h the b o n e as a thin blue line ( F i g . 1 7 - 8 / 1 ) . T h e r e l a t i o n s h i p o f t h e f a c i a l n e r v e

Procedure

to the h o r i z o n t a l s e m i c i r c u l a r c a n a l is d e f i n e d (Fig. 1 7 - 8 8 ) . T h e three canals are drilled ( o n e b y o n e ) a n d their c o n t e n t s carefully r e m o v e d b y s u c t i o n a n d t h e use o f h o o k s (Fig.

1 7 - 8 C ) . T h e s p a c e i s filled w i t h

Gelfoam saturated with streptomycin sulfate.

For

this

approach,

the

patient

lies

supine.

The

preparation a n d draping of the patient are the s a m e as for a s t a n d a r d ear p r o c e d u r e ,

with the exception

that a larger area of the head is s h a v e d . T h e patient's h e a d is p o s i t i o n e d at t h e foot of t h e table to a l l o w

Retrolabyrinthine Approach to the Cerebellopontine Angle and Sectioning of the Vestibular Nerve

the

surgeon's

T h e patient since

legs

frequent

patient's

ample

room

beneath

the

table.

must be securely strapped to the table,

left

side-to-side low;er

rotation

abdomen

is

is also

needed.

The

prepared

and

d r a p e d f o r h a r v e s t i n g o f a n a b d o m i n a l fat g r a f t . T h e postaurictilar incision is m a d e as usual but is located

further

posteriorly—2

to 3 cm

(at

its

most

p o s t e r i o r p o s i t i o n ) — t o allow drilling p o s t e r i o r to the

Aim

sigmoid

sinus,

compression

this

of

is

the

essential

sigmoid

for

sinus,

complete which

de-

permits

proper angulation and visualization into the cerebelExposure

of

eighth cranial

the nerve

cerebellopontine with

angle

preservation

and

of the

the

laby-

rinth.

lopontine

angle.

The

incision

runs

in

a

semilunar

fashion and is carried t h r o u g h the p e r i o s t e u m of the mastoid cortex, avoiding the temporal muscle superiorly. T h e p e r i o s t e u m is then elevated a n d the ear held

Highlights

forward

with

cerebellar

retractors.

Retractors

p l a c e d in a s u p e r i o r - t o - i n f e r i o r d i r e c t i o n will h o l d t h e t e m p o r a l m u s c l e o u t o f t h e s u r g i c a l field. Using

1. M a n n i t o l m a y be g i v e n to aid s h r i n k a g e of the cerebellum.

as

2. T h e a n t e r i o r limit of the d i s s e c t i o n is the posterior s e m i c i r c u l a r c a n a l . 3. The sigmoid sinus must be adequately decompressed and

mobilized.

the

largest cutting

bur and

suction

irriga-

tion, drilling is b e g u n . T h e m a s t o i d cortex is r e m o v e d in

a

saucerize opening

routine the as

mastoidectomy.

edges

wide

as

and

to

possible.

Care

keep

the

Removal

is

taken

to

lateralmost of bone

is

e x t e n d e d b e h i n d t h e s i g m o i d s i n u s for a d i s t a n c e o f up to 1 c m ; the b o n e is thinned to eggshell thickness,

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

309

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o and

final

removal

accomplished

from

later

the

with

for e m i s s a r y v e i n s that

sigmoid

and

the d i a m o n d

bur.

run

from

dura

is

Be alert

the sigmoid sinus

lated e n d of t h e posterior s e m i c i r c u l a r canal a n d runs in a

plane

canal.

in

line with

the horizontal

With adequate exposure,

be seen anterosuperiorly,

to the mastoid cortex. At this point the operating m i c r o s c o p e is b r o u g h t

semicircular

t h e fifth

nerve may

Inferiorly the ninth, tenth,

and eleventh nerves can be seen. T h e seventh nerve

mastoidectomy is completed as

lies m e d i a l to the e i g h t h a n d c a n be visualized with

described in C h a p t e r s 5 and 7, a n d the basic land-

g e n t l e retraction of the latter. O f t e n the lateral b r a n c h

marks (the

of the anteroinferior cerebellar artery is seen between

into the

and

field.

the

The

horizontal semicircular canal,

course

of

the

facial

nerve)

the incus,

are

visualized.

the

seventh

and

eighth cranial

nerve

rootlets (Fig.

W i t h t h e s e l a n d m a r k s , accurate identification of the

1 7 - 1 0 / 1 ) . A r a c h n o i d a d h e s i o n s m a y o b s c u r e the cer-

posterior semicircular canal can be m a d e . T h i s rep-

ebellopontine angle and

resents

section

the

exposure

anterior

into

the

limit

for r e m o v a l o f b o n e a n d

cerebellopontine

angle;

if

bone

with

a

sharp

its s t r u c t u r e s .

hook

may

be

Careful

needed

dis-

to

lyse

these adhesions.

r e m o v a l is not c o m p l e t e up to the posterior semicir-

At

this

level,

the

eighth

nerve

consists

of one

c u l a r c a n a l , a t r o u b l e s o m e r i d g e o f b o n e will h i n d e r

trunk.

adequate exposure to the angle. Interiorly the dissec-

perior to the c o c h l e a r s e g m e n t . Usually, careful high-

tion is c o n t i n u e d into the infralabyrinthine a n d retro-

p o w e r i n s p e c t i o n o f t h e n e r v e t r u n k will r e v e a l t h e

facial cell t r a c t s . B o n e r e m o v a l i s a l s o n e c e s s a r y h e r e

cleavage

for a d e q u a t e e x p o s u r e o f t h e c e r e b e l l o p o n t i n e a n g l e

often h i g h l i g h t e d by a small v e s s e l on the surface of

and

the nerve (Fig.

the

dura

eighth

cranial

is.followed

superiorly

nerve.

The

medially and

located,

is

posterior

fossa

the jugular bulb,

exposed.

The

superior

if

limit

T h e v e s t i b u l a r s e g m e n t o f the n e r v e lies su-

patients,

plane

separating

the

segments;

it

is

1 7 - 1 0 8 ) . (In a p p r o x i m a t e l y 2 0 % o f

this p l a n e is difficult to d i s c e r n . ) U s i n g a

small hook, the cleavage plane is developed. Section-

w i t h i n t h e i n f r a l a b y r i n t h i n e cell tract will b e the h a r d

ing of the vestibular division

bone of the labyrinth.

hook

Although it is not necessary

two

or

microscissors,

facial

or cochlear

is d o n e with a sharp

carefully

avoiding

injury

to

t o " b l u e - l i n e " it, c o n s t a n t a w a r e n e s s o f t h e l o c a t i o n

the

of

vestibular d i v i s i o n is s e c t i o n e d the e n d s will retract,

the

descending

portion

of

the

facial

nerve

is

n e e d e d t o a v o i d i n j u r y t o it. T h e e n d o l y m p h a t i c s a c

irrigation.

The

removal Bill's

and

island

the

large

diamond

avoids of b o n e

diamond bur

tearing

bur and

suction

allows

for

safer

of

dura

or

is often

the

17-10C).

As

the

After sectioning of the nerve, the cerebellopontine

B o n e removal from the posterior fossa dura is n o w with

(Fig.

leaving a 3- to 4 - m m gap.

is located within the dura at this level. completed

nerves

bone sinus.

left o v e r t h e s i g m o i d

a n g l e is i n s p e c t e d for g o o d

hemostasis.

The previ-

o u s l y h a r v e s t e d a b d o m i n a l fat i s c u t i n t o l o n g s t r i p s , which

are

placed

just

into

the

dural

opening

t h e tails b r o u g h t o u t t o the m a s t o i d c a v i t y . and

tight

with

Careful

placement of these strips has been

found

sinus to protect it d u r i n g retraction or further drilling

to p r o v i d e a g o o d seal a g a i n s t p o s t o p e r a t i v e c e r e b r o -

medially

spinal fluid

T h e dural o p e n i n g is m a d e with a N o . 59S Beaver

leakage.

The l o n g tails are t h e n

into the

mastoid and antrum, is

and

knife or similar sharp instrument. T h e

first i n c i s i o n

incision

parallels

between

the

a p p l i e d a n d left i n p l a c e f o r t w o d a y s .

sinus and the e n d o l y m p h a t i c sac interiorly (Fig.

17-

the

sigmoid

sinus

and

runs

closed.

A

mastoid

folded

the postauricular

pressure

dressing

is

9/1). T h e superior incision parallels the superior petrosal s i n u s a n d

runs in

the sinodural angle.

(Care

Intraoperative Complications or Problems

must be taken to avoid injury to the vessels and the cerebellum

immediately

under the dura.) T h e

dural

flap c r e a t e d i s h i n g e d a n t e r o m e d i a l l y a t t h e l e v e l o f the posterior semicircular canal (Fig.

17-98);

it is With good training and expertise,

draped o v e r the canal a n d a stay suture is placed if needed.

Long

Cottonoids

are

placed

over

the

ex-

p o s e d c e r e b e l l u m (for p r o t e c t i o n ) a n d g e n t l e r e t r a c tion

is

bluntly

probed

The to

cisterna

provide

a

lateralis profuse

inferiorly

is

cerebrospinal

remarkably

free

of

this p r o c e d u r e

intraoperative complications.

T h e most c o m m o n p r o b l e m s are caused by bleeding from injury to the s i n u s e s ;

they are treated as dis-

c u s s e d in C h a p t e r 5 (Translabyrinthine A p p r o a c h to

the

the Internal Auditory Canal).

With careful prepara-

cerebellum to relax. G o o d visualization of the cere-

tion and m e t i c u l o u s e x p o s u r e ,

o t h e r p r o b l e m s listed

b e l l o p o n t i n e a n g l e a n d its s t r u c t u r e s i s t h e n o b t a i n e d .

there should be avoided.

fluid

FIGURI-'

applied.

is

leak if one

has

not occurred;

this allows

T h e e i g h t h n e r v e lies near the level o f the a m p u l -

Additional

potential

prob-

lems are those a c c o m p a n y i n g a m a s t o i d e c t o m y .

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l Vertigo

F1CUKE 17-9 FIGURE 17-10.

312

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

313

Pertinent Histopathology FIGURE

17-11

canal sided

This

temporal

bone was

from

an

individual

who

u n d e r w e n t fenestration of the horizontal semicircular

appear

for a v e r t i g i n o u s s y n d r o m e . T h e v e r t i g o sub- | temporarily. to

be

This

simple

section

shows

conservative

that

what I

"fenestrations"

result in localized reactions with n e w b o n e formation. ,

FIGURE This

17-12

patient

underwent

an

unsuccessful

w i n d o w l a b y r i n t h o t o m y " for v e r t i g o . sorineural

hearing

loss

lively did

not c h a n g e

that

was

"round

A severe sen-

present

postoperatively.

preopera-

This

section

s h o w s the marked localized inflammatory reaction in the

round

window

niche

that

seemingly m i n o r surgical trauma,

is

associated

with

314

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

CHAPTER 18 Intratemporal Facial Nerve Surgery

Middle c a r caviry

T h e a i m of the p r o c e d u r e s d i s c u s s e d in this c h a p -

Transmastoid Approach

ter is to re-establish safe c o n t i n u i t y of the a x o n s of the

facial

trauma the

or

nerve

that

disease.

procedure

have

This

involves

rcanastomosing.

been

compromised

remains freeing,

constant

by

whether

decompressing,

A c o m p l e t e d i s c u s s i o n of the indi-

c a t i o n s for s u r g i c a l e x p l o r a t i o n o f t h e facial n e r v e o r

1

T h o s e of a simple mastoidectomy

a n y of its s e g m e n t s is o u t s i d e the s c o p e of this atlas;

2

T h o s e o f a f a c i a l r e c e s s a p p r o a c h (if n e e d e d )

3

I d e n t i f y i n g t h e d i f f e r e n t s e g m e n t s o f t h e facial

here ate intended onlv

the c o m m e n t s to a

t h o r o u g h u n d e r s t a n d i n g of specific

to contribute procedures

I n f r a t e m p o r a l facial n e r v e p a r a l v s i s c a n b e c a u s e d b v I-TCUKF

nerv : a n d s k e l e t o n i z i n g t h e facial c a n a l 1

m a y a l s o b e laid t o p r o t e c t t h e c e r e b e l l u m a n d h e l p

bleeding

in d e v e l o p i n g the plane. D e v e l o p i n g the proper plane

abundant.

will p r o d u c e l e s s b l e e d i n g .

traverse the capsule interiorly. Usuallv the anteroi .-

At

this

point

the

lateral

end

of

the

tumor

is

within

tumor growth.

away

area

vestibular and

is

brought

facial

into

nerves are

tumor,

which the

occasionally

ninth

nerve

:

s

m- v

( e r i o r c e r e b e l l a r a r t e r y h a s b e e n p u s h e d i n f e r i o r l y '~y

m o b i l i z e d from t h e facial n e r v e . B y r o t a t i n g the table the

the

With large tumors,

S u p e r i o r l y t h e fifth

n e r v e m a y ere? s

The

superior

the c a p s u l e in large t u m o r s ; o c c a s i o n a l l y , the s e v e n ; i

identified.

Using a

nerve may

view.

traverse the superior e d g e of the

tumo:.

FIGURE 19-5.

336

T u m o r s of the Middle and Inner Ear

337

Tumors of the M i d d l e and Inner Ear During mobilization and tumor removal, these struc-

loss; h o w e v e r , if b o n e removal has b e e n c o m p l e t e d

t u r e s m u s t b e w a t c h e d for a n d p r o t e c t e d .

there are no b o n y ledges against which to w e d g e the

A f t e r a d e q u a t e d e b u l k j n g , t h e p l a n e for t h e facial

packing. ally;

to

drill, c r e a t i n g a w h i p p i n g a c t i o n w i t h t h e S u r g i c e l .

be

rolled

toward

the

surgeon.

It

is

important

in

Large packs hinder dissection more medi-

nerve is further developed and the t u m o r continues

addition,

b o n e w a x draped over Bill's island; a long strip of

to

follow

the

and

facial

nerve

removing

the

to

the

Cottonoid is then draped over the area and the entire a malleable retractor h o o k e d to the cerebellar retrac-

to be developed.

nerve usually thins considerably,

making

tors.

Again, bleeding usually can be controlled; the

the d i s s e c t i o n difficult. Often it is n e c e s s a r y to return

objective is

to the posterior, inferior, and superior borders of the

without

t u m o r t o d e v e l o p t h i s p l a n e (if n e e d e d Always

for m a n e u -

Bleeding.

Inadvertent

injury

to

the

i m m e d i a t e l y will control the b l e e d i n g . C a u t i o n m u s t be

the

e n h a n c e visualization

(Fig.

tween

tumor

the

remaining

tumor

is

19-6/:). and

the

Bulb

the

of

pushing

Jugular

a n t e r i o r l y . O n c e the facial n e r v e h a s b e e n freed from bulk

avoid

farther medially

jugular bulb is signaled by profuse bleeding. Packing

the

to

to continue dissection

hindrance.

tumor

tumor,

try

packing with

the porus acusticus

the

the

vering).

the

c o m p l e x is retracted with the suction irrigator or with

as

continues facial

to cover

plane

tumor

At

brainstem,

is

the

One

separating

this

m a y be caught in

inward, which m a y stretch the thinned nerve. best

to

packs

( a l t h o u g h difficult) to a v o i d p u s h i n g the t u m o r m a s s It is

solution

the

removed

to

T h e plane be-

the

brainstem

developed and care is exercised superiorly

is

for t h e

exercised

since

the

ninth,

tenth,

and

eleventh

n e r v e s are in this area a n d m a y be injured by injudicious packing. For small tears in the jugular bulb, packing

may

control

the

bleeding

and

allow

the

fifth n e r v e a n d i n f e r i o r l v f o r t h e a n t e r o i n f e r i o r c e r e -

procedure to c o n t i n u e . O n l y large pieces of packing

bellar artery (Fig.

material

1 9 - 6 £ ) . Vessels that traverse the

are

to be

used

here,

in order to

prevent

tumor surface are dissected away, if possible; if not,

d i s p l a c e m e n t of material into the l u m e n of the vein

they are carefully clipped or cauterized. With careful

and a

d i s s e c t i o n , total r e m o v a l o f t h e t u m o r c a n b e a c c o m -

concern with tears in the s i g m o i d ) . For large tears, it

p l i s h e d i n a l m o s t all c a s e s .

i s o f t e n n e c e s s a r y a n d s a f e r t o tie t h e v e i n o f f i n t h e

Before closure,

sufficient time

must be taken to

e n s u r e that a d e q u a t e h e m o s t a s i s is o b t a i n e d the c e r e b e l l o p o n t i n e angle. abdomen

and

placed

in

Fat

is

taken

long strips just

within

against

postoperative cerebrospinal

n e c k by e x t e n d i n g t h e postauricular incision interio r l y ( f o r all n e u r o l o g i c p r o c e d u r e s t h e u p p e r n e c k i s

from

the

included

inside

the

packed intraluminally to prevent back-bleeding,

dural o p e n i n g ; this has b e e n found to provide a g o o d seal

resulting p u l m o n a r y e m b o l u s (this is also a

fluid

leak-

Facial

in

the draping).

Nerw

Avulsion.

If

T h e jugular bulb is then

the

facial

avulsed during tumor removal,

nerve

is

a decision

lost

a g e . T h e l o n g tails o f the strips are t h e n folded into

made whether to attempt immediate or delayed

the m a s t o i d cavitv a n d a n t r u m , and the postauricular

habilitation.

incision is closed.

Because

the best

and

most

or

must be re-

consistent

results are o b t a i n e d from i m m e d i a t e rehabilitation, it should be attempted if possible. If the brainstem side of the avulsed

Intraoperative Complications or Problems

mobilized

in

maneuver, obtained

is long e n o u g h ,

an

its e n t i r e t y

from

additional

1-cm

(bypassing

the

its c a n a l . length

With

of

labyrinthine and

this

nerve

is

temporal

1. S i g m o i d and superior petrosal sinus bleeding.

course of the nerve) and an end-to-end anastomosis

2. Jugular bulb bleeding.

m a y be a t t e m p t e d . If p o s s i b l e , a s u t u r e is placed to

3. Facial nerve avulsion.

hold

4. Vital sign c h a n g e s .

has been

Sinus Bleeding.

in a p p o s i t i o n ) . If this is n o t feasible, a h y p o g l o s s a l -

B l e e d i n g a r i s i n g from i n j u r y to the

sinus during bone removal may be profuse at times. Although alarming, with proper m a n a g e m e n t it may

FIGURE 19-6.

nerve is found and

t h e i n f r a t e m p o r a l p o r t i o n o f t h e facial n e r v e m a y b e

the avulsed

ends

placed around

together (collagen

[Avitenej

the t w o e n d s to hold them

facial n e r v e a n a s t o m o s i s i s p e r f o r m e d l a t e r . Vital Sign Changes. V i t a l s i g n s a r e c o n s t a n t l y m o n -

be controlled without serious consequences. Sigmoid

itored

bleeding arising from e m i s s a r y veins usually can be

ous cardiac monitoring is d o n e , as well as monitoring

controlled

of blood p r e s s u r e with arterial lines.

b y full e x p o s u r e o f t h e v e i n a n d b i p o l a r

throughout tumor removal surgery.

Continu-

W i t h a n y rise

cautery; packing with b o n e wax or Surgicel is another

or c h a n g e in blood pressure or pulse regularity, the

o p t i o n . For tears w i t h i n the s i n u s itself, p a c k i n g with

surgeon

S u r g i c e l will c o n t r o l t h e i m m e d i a t e p r o b l e m o f b l o o d

Cottonoid packing is r e m o v e d in order to eliminate

is notified,

traction

is stopped,

and

large

CHAPTER 20 Plastic Surgery of the Pinna T h e p i n n a , or auricle, is the projecting part of the

Highlights

ear t h a t lies o u t s i d e t h e h e a d ; its b a s i c a n a t o m y i s s h o w n in Figure 2 0 - 1 .

It consists of two types of

tissue: elastic (yellow) cartilage and, in the ear lobe, fibroareolar tissue.

pressure

on

normal in a they

vessels.

Usually

responses

return

to

few minutes and surgery continues,

it

has

usually

time

improved

the brainstem circulation

from

tumor

debulking

of

superior, the

anterior,

Blood

is

and

supplied

superficial

to

temporal

p o s t e r i o r aurithe

pinna

and

by

posterior

the

greater

auricular

and

auriculotemporal

Pertinent Histopathology

after

the

repair;

even

a

lightweight

small

branch

of

the

vagus

nerve

in

the concha

Pitfalls

bowl. This chapter describes several surgical proced u r e s for repair a n d r e c o n s t r u c t i o n o f t h e p i n n a .

and

1. F a i l i n g to p e r f o r m a Z - p l a s t y o f t e n r e s u l t s in a FIGURE

notch at the free m a r g i n of the lobe a n d a d e p r e s s e d

19-7

m e n t of blood loss is important to prevent earlv signs of s h o c k ( i n c r e a s e d pulse, d e c r e a s e d B P ) from offset-

hole

e a r r i n g will e n l a r g e the h o l e p o s t o p e r a t i v e l y .

nerves,

release of pressure, a n d total t u m o r r e m o v a l can be performed safely. Constant monitoring and replace-

2. Do not u s e a p o s t - t y p e earring to m a i n t a i n the earring

auricular arteries, and it is innervated by b r a n c h e s of

a

i s left b e h i n d , i t m a y b e r e m o v e d e l e c t i v e l y i n a b o u t By that

the

1. M a k e a Z-plasty or V - p l a s t y at the free m a r g i n to prevent postoperative notching.

the mastoid branch of the lesser occipital nerve, and

surgery but only perform a subtotal removal; if t u m o r months.

by

muscles.

branches ting the effect of vessel traction or s p a s m ( d e c r e a s e d pulse, increased BP).

recur, a decision is m a d e w h e t h e r to continue

six

scalp cular

It is c o n n e c t e d to the head and

This horizontal section of a temporal b o n e show?

Treatment of the Cleft Ear Lobe

the p r e s e n c e o f a n acoustic n e u r o m a .

scar. 2. If the

patient wears an

e a r r i n g too s o o n after

the r e p a i r , a n e n l a r g e d e a r r i n g h o l e will r e s u l t P a t i e n t s are often s e e n in the clinic w i t h cleft ear l o b e s s e c o n d a r y t o t r a u m a f r o m p i e r c i n g t h e e a r for e a r r i n g s . T h e y m o s t often p r e s e n t with a h e a l e d cleft, but o c c a s i o n a l l y w i t h a " f r e s h " or i n c o m p l e t e cleft;

Instruments

v e r y r a r e l y a c o n g e n i t a l cleft is s e e n . R e g a r d l e s s of the p r e s e n t a t i o n , t h e t r e a t m e n t i s the s a m e

No. 11 and N o . 15 scalpel blades and handles. T w o skin h o o k s , either single or double h o o k type. 0.5-mm ophthalmic forceps.

Aim

Fine Storz "stitch" scissors. S u t u r e s : 5-0 Vicryl on a cutting n e e d l e , 6-0 c h r o m i c or 6-0 n y l o n on a small cutting n e e d l e , 0 p r o l e n e

To c o r r e c t a cleft e a r l o b e d e f e c t

or nylon

340

341

Plastic S u r g e r y of the P i n n a

Plastic Surgery of the Pinna

Procedure

2.

Stay as close as possible to

the

stalk of the

keloid during excision, in order to preserve as m u c h Ant. auricular muscle

normal skin of the ear lobe as possible. Lidocaine 1 to 2% with 1:100,000 e p i n e p h r i n e is u s e d . First t h e e d g e s o f t h e cleft a r e e x c i s e d - I f t h e cleft i s n o t q u i t e c o m p l e t e , t h e s m a l l b r i d g e o f s k i n also

is

(Fig.

excised.

20-2-A-C).

A

Z-plasty

One

can

is

also

fashioned be

made

anteriorly

Pitfalls

posteriorly,

but this is not n e c e s s a r y . A Z-plasty s h o u l d also be made

at

the

free

margin

of the

lobe

to

prevent

a

small notch from forming during the healing process A l t e r n a t i v e l y , the free m a r g i n c a n be c l o s e d in a " V "

1. R e p i e r c i n g of the lobe after successful treatment of a keloid is not r e c o m m e n d e d . 2. Failing

to

prevent

a

recurrence

p r o b l e m after e x c i s i o n

the

common

to h a v e a p i e r c e d e a r , a l e n g t h of 0 p r o l e n e s u t u r e is

follow-up

f o r m e d i n t o a 1-in l o o p p a s s i n g t h r o u g h t h e f o r m e r

the best m e t h o d s of preventing a recurrence.

and

the use

of

of a

is

t o n g u e - a n d - g r o o v e f a s h i o n . I f t h e p a t i e n t still w i s h e s

keloid.

intralesional

most Close

steroids are

earring site. S o m e patients, not wishing to have the

3. T h e patient with large keloids m u s t be advised

l o o p o f s u t u r e i n t h e i r l o b e for s e v e r a l w e e k s , m a y

that the ear lobe m a y be less fleshy after e x c i s i o n of

decide

the

the k e l o i d ; t h a t o w i n g t o t h e m a s s o f t h e k e l o i d , little

repair has healed. T h e fibroareolar tissue is closed

fibrofatty t i s s u e is a v a i l a b l e for a d v a n c e m e n t into t h e

with

w o u n d for c l o s u r e ; that t h e l o b e m a y b e s m a l l e r after

simply

to

interrupted

have

the

ear

5-0 Vicryl a n d

repierced the skin

after

is closed

excision of the keloid, o w i n g to the excision of skin

with interrupted 6-0 nylon or 6-0 c h r o m i c sutures. B a c i t r a c i n o i n t m e n t is a p p l i e d to t h e i n c i s i o n for a few d a y s . 6-0 nylon sutures are r e m o v e d at four to five d a y s . I f 6-0 c h r o m i c s u t u r e s a r e u s e d , t h e p a t i e n t can be seen at seven to 10 days, at which time the

on both surfaces of the lobe; a n d that the lobe m a y be rotated slightly anteriorly after the excision of a lateral keloid a n d slightly posteriorly after the excision of a m e d i a l keloid.

r e m a i n i n g w i s p s o f s u t u r e c a n b e g e n t l y w i p e d off. A n e a r r i n g m a y b e w o r n after four w e e k s .

Instruments Treatment of Keloids No. 1 and N o . 15 scalpel blades and handles. 0.5-mm ophthalmic forceps. Keloids are a c o m m o n

problem of the ear lobe,

A fine n e e d l e h o l d e r .

especially in blacks. T h e y usually involve the medial

Storz "stitch" scissors.

aspect of the lobe, a n d m o s t often are the result of

Skin hooks, either single or double.

d e e p dermal injury to the lobe of the ear w h e n the

Sutures: 5-0 c h r o m i c or Vicryl, a n d 6-0 c h r o m i c or 6-

ears are pierced painful

when

for e a r r i n g s .

holding a

telephone

the ear or w h e n sleeping. to c a u s e a

Large lesions can be

0 n y l o n on a small c u t t i n g n e e d l e .

receiver against

A n y keloid large e n o u g h

c o s m e t i c or functional defect should

be

excised.

Aim

Procedure T h e treatment of keloids involves three treatment modalities,

steroid

therapy,

pressure

therapy,

and

excision. T h e s e modalities are often used at different To excise and prevent the recurrence of the ear lobe keloid.

times in the treatment of the s a m e keloid. Small keloids can be treated with injections of 40 mg per ml of triamcinolone acetonide every four to six w e e k s . T h e s t e r o i d c a n e i t h e r b e d e l i v e r e d w i t h a

Highlights

Dermajet apparatus or injected into the d e r m i s with a 25-

or

27-gauge

needle.

A

Dermajet

needleless

injector d i s p e n s e s 0.1 ml of the steroid s o l u t i o n in a 1. T h e key to treatment is to prevent recurrence

fine

droplet

form

uniformly

into

the

tissues;

this

after e x c i s i o n . T h i s is a c c o m p l i s h e d with intralesional

avoids the b o l u s injection of steroids that can result

steroid injections and the use of pressure earrings.

from direct n e e d l e injection i n t o d e n s e s c a r tissue.

343

Plastic S u r g e r y of the Pinna

O v e r z e a l o u s injection can c a u s e skin a t r o p h y , telan-

before

giectasis, a n d h y p o p i g m e n t a t i o n . It m a y t a k e six to

requires more extensive surgery.

the clot organizes.

An

organized

hematoma

12 m o n t h s to resolve the keloid. It is a l s o p o s s i b l e to treat small keloids with pressure therapy.

A pressure-type clasp earring (Padgett

Co, Kansas City, M O ) m a y supply e n o u g h pressure to blanch

the capillaries supplying the fibrous tissue

and cause a regression of the lesion. It must be worn continuously

for s e v e r a l

months.

is

the

can

taken

off

keloid

W h e n the earring

recur;

therefore,

it

is

Aim To drain

the hematoma,

prevent reaccumulation,

avoid s e c o n d a r y cellulitis or perichondritis, a n d prevent

the

deformity

caused

by

organization

of

the

h e m a t o m a (cauliflower ear).

probably best to c o m b i n e use of the pressure earring with m o n t h l y steroid injections.

Highlights

F o r k e l o i d s t h a t a r e t o o l a r g e for p r e s s u r e t h e r a p y or that do not r e s p o n d to s t e r o i d s , e x c i s i o n is indicated. T h e entire keloid should be excised. Delicate handling is necessary to prevent trauma to the surr o u n d i n g tissues. If the keloid is especially large, it is i m p o r t a n t to free up s u r r o u n d i n g fibrofatty tissue t o fill i n t h e s o f t t i s s u e d e f e c t . A W - p l a s t y o r Z - p l a s t y

1. T h e m o s t important s t e p is the p l a c e m e n t of a w e l l - m o l d e d dressing to prevent a recurrence 2. The

incision

should

be

hidden

or should

run

favorably with the a n a t o m y of the pinna. 3. A drain m a y be n e c e s s a r y w h e n treating a large hematoma.

is u s e d to c a m o u f l a g e the repair. S o m e t i m e s a small r o t a t i o n a l flap m u s t b e u s e d for c l o s u r e . S t e r o i d s c a n be injected directly into the surgical site at the end

Pitfalls

o f t h e p r o c e d u r e . 5 - 0 c h r o m i c o r V i c r y l i s u s e d for deep sutures and 6-0 c h r o m i c or nylon

is used

on

1.

R e c u r r e n c e o f t h e h e m a t o m a o w i n g t o a n in-

adequate

the skin.

dressing.

B a c i t r a c i n i s a p p l i e d for a f e w d a y s . N y l o n s u t u r e s can b e r e m o v e d after four t o five d a y s . W h e n e x c i s i o n

I n s t r u m e n t s a n d Supplies

alone is u s e d the r e c u r r e n c e rate is o v e r 50vl; therefore, the s u r g i c a l site s h o u l d be injected w i t h s t e r o i d s

No. 11 or No. 15 scalpel and handle.

every month

Curved

the

scar is

for a p p r o x i m a t e l y six mature.

using the Dermajet, blade against

To stabilize it

m o n t h s or

the ear kibe

is helpful

until when

to p l a c e a t o n g u e

the lateral surface of the lobe.

At the

first s i g n o f r e c u r r e n c e , a p r e s s u r e e a r r i n g s h o u l d b e added to the treatment regimen

hemostat (mosquito)

0.25-in Penrose drain (optional) Cotton balls. Povidone-iodine (Betadine) ointment 5 0 - 5 0 m i x t u r e o f m i n e r a l oil a n d

Betadine solution

(optional). 4 x 4

"Fluffs."

2-in r o l l e d b a n d a g e s 2-0 n y l o n or p r o l e n e on a large cutting n e e d l e

Traumatic Injuries of the Pinna

Hibiclens or Betadine scrub. Normal saline irrigating solution.

Injuries of the p i n n a are classified as follows:

Procedure

1. T r a u m a t i c h e m a t o m a with or without cellulitis or

perichondritis Lidocaine 1%

2. Laceration without tissue loss

with 1:100,000 epinephrine can be

3. Laceration with skin or cartilage loss, or both.

u s e d as a field b l o c k or i n j e c t e d l o c a l l y . T h e e a r is

4. Total amputation of the pinna.

p r e p a r e d with H i b i c l e n s or B e t a d i n e scrub. A vertical curvilinear incision is m a d e over or along the side of the

hematoma

(usually

under either

the

helical

or

a n t h e l i c a l fold to c a m o u f l a g e it). It is b e t t e r to m a k e

Hematoma of the Pinna

a n i n c i s i o n l a r g e e n o u g h for g o o d d r a i n a g e a n d deal with the resultant scar later than to be faced with a persistent

A

hematoma

of

the

pinna

is

caused

by

blunt

trauma a n d m o s t often affects t h e lateral s u r f a c e (Fig. 20-2D).

It

should

be

drained

as

soon

as

possible

or

perichondritis. used

to open

hematoma

recurrent

hematoma

and

secondary

A curved mosquito hemostat m a y be up a n y loculations.

should

be

taken

A culture of the

if cellulitis

is

present.

344

Piasi ic S u r g e r y of the Pinna

The

hematoma

can

then

be

Plastic S u r g e r y of the P i n n a

irrigated

gently

Highlights

with

t i m e a s t e n t m u c h like t h a t for a h e a r i n g aid c a n be

s t e r i l e n o r m a l s a l i n e . A >/i-in P e n r o s e d r a i n o r r u b b e r

placed to prevent post-traumatic stenosis of the canal

b a n d d r a i n s h o u l d b e u s e d for e x t e n s i v e h e m a t o m a s .

1. Intracartilaginous s u t u r e s are often

Skin

2. Apparently

sutures

should

then

approximate

the

skin

of

nonvital

tissue

(Fig

necessary.

should

be

saved

l a r g e i n c i s i o n s b u t still a l l o w a d e q u a t e d r a i n a g e . N e x t

whenever possible.

cotton balls saturated

sists, the skin of the pinna h a s a r e m a r k a b l e abtlit.

with

B e t a d i n e o i n t m e n t (or a

If a c u t a n e o u s l i n k o f s k i n

per1

2 0 - 2 H ) . A central hole should be drilled to allow

h e a r i n g . T h e stent s h o u l d be w o r n for three Bacitracin

is applied

t o w i t h s t a n d v a s c u l a r c o m p r o m i s e . T h e n o n v i t a l tis-

crusting.

If

are formed into s h a p e s that precisely c o r r e s p o n d to

sue

dressing

with

the folds of the

debrided

additional

pinna o v e r l y i n g the

piece of cotton

should

hematoma.

be

molded

An

to

fit

into the postauricular c r e a s e (Fig. 2 0 - 2 E ) . A n exact fit

is

necessary

hematomas.

to

prevent

reaccumulation

of

3.

then

days

later

and

can

be

then.

Use

of

pinna

a

stent

with

external

auditory

canal

hematomas

is

extensive,

molding

but

(like

without

a

that

usually

"Fluffs"

two and

will

a

suffice.

2-in

rolled

A

Pitfalls

mastoid

bandage are

the

mattress

1. Post-traumatic tattooing d u e to i n c o m p l e t e de-

mastoid

s u t u r e s ) s h o u l d b e a p p l i e d a n d w o r n for t w o t o t h r e e

dressing and

cotton

balls can

General anesthesia

needed

and

the cotton

two to three days.

bolsters are

rehas

type

of

precise

cotton

packing

with

tissue loss is similar to that after the resection of a

teral

cultures should

antibiotics

started.

through-and-through

A

suction

be

taken and

Penrose irrigation

or

system

a

mav

be necessarv. If there is evidence of cartilage necrosis, w i d e d e b r i d e m e n t o f n e c r o t i c soft t i s s u e a n d cartilage is needed. T h e reconstruction of any defects resulting from p e r i c h o n d r i t i s is similar to that p e r f o r m e d after neoplasm resection (described below).

In

Total Amputation of the Pinna Fortunately,

Procedure

putated Usually can

be

17,

used.

compromised

total

or

subtotal

p i n n a is a rare o c c u r r e n c e . lidocaine with If

there

blood

epinephrine should

are

flaps

supply, be

1:100,000 epinephrine 1V
i u.rtie.il | K 1 radical. I'M modilied. 1X5, I'M mucoid, histopathology of. 199 myringotomy and tubes for. 164-171. Sec al-l intact bridge mastoidectomy as, 63, 67, 68 labyrinthectomy as, 71, 73 . 7 4 - 7 5 middle ear dissection as. 75, 76-81 middle fossa approach to internal auditor,' canal as, 93, 95-96, 97 ossiculoplasty as, 62, 63, 65-66 petrous drainage as, 71, 72 radical mastoidectomy as, 63, 67, 70, 71 modified, 63, 67, 69 retrolabyrinthine approach to cerebellopontine angle as, 82, 85, 87, 88 Simple mastoidectomy as, 4 4 - 4 7 , 48 transcanal'labyrinthectomy as, 82, 85, 86 transcochlear approach to skull bone as, 90, 92, 93, 94 translabyrinthine approach to internal auditory canal as. 87, 89, 90, 91 transmastoid facial nerve decompression as, 59, 60-67 underlay graft of tympanic membrane as, 62, 63, 64 facial nerve in, 17

Temporal bone (Continual) histology of, 2 3 2 7 imaging of by computed tomography, 28, 29-31, 34 by magnetic resonance, 28, 3 7 - 3 4 high resolution, 2 8 - 3 5 paraganglioma of, MR imaging of, 32 pneumatizaHon of, 16-17 removal of, 3 9 - 4 3 resection of, subtotal, 153, 755, 156 total, 136, 157-75S Tensor tympanic muscle, 12 Terminal incisure, 4 Thiersch graft, 140-143 debridement of granulation tissue from mastoid cavity for, 141-143 harvesting thin skin for, 742, 143 of mastoid cavity, 142, 143 Thrombophlebitis, sigmoid sinus, complicating suppurative otitis media, 194, 196-197, 198 Tissue adhesions, for ossicular chain grafting, 223 Transcanal approach, to external ear canal and middle car, 121-127, 128 closure in, 125 I evaluation of flaps in, 123, 124, 125 exposure of middle ear in, 125, 726 highlights of, 121 incisions in. 123, 124 injection of local anesthetic in, 123, 724 inspection and cleansing in, 121, 123 packing in, 127, 728 pitfalls in, 121 revisions in, 125, 127 to intra temporal facial nerve surgery, 317, 379, 320 to labyrinthectomy, for incapacitating peripheral vertigo, 302, 306 Transcanal labyrinthectomy, 82, 85. 86 Transcochlear approach, to skull bone, 90, 92, 93, 94 Translabyrinthine approach, to acoustic neuromas, 331-338 aim of, 331 highlights of, 331 intraoperative complications or problems with, 3 3 7 - 3 3 8 pitfalls of, 331 procedure for, 331-337 to internal auditory canal, 87, 89, 90, 9? Transmastoid approach, to infratemporal facial nerve surgery, 315-317, 378 to labyrinthectomy, for incapacitating peripheral vertigo, 307, 308 Transmastoid labyrinthine dissection, 71, 73, 74-75 r

Transmeatal permanent aeration tubes, for otitis media, 171-173 Transmoid facial nerve decompression, 59, 60-61 Transverse crest of fundus, 21 Trigeminal nerve, auriculotemporal branch of, 8 Tumor(s), external auditory canal, 151, 153, 754-155, 156. 757-758' inner ear, 331-338 middle ear, 325-331 glomus tympanicum, 325-327 glomus jugulare, 327-331 of pinna, total, plastic surgerv for, 347, 349-353 Tympanic artery. 14