Schriftenreihe Neurologie

Transcription

1 Schriftenreihe Neurologie 18 Neurology Series Herausgeber H.I Bauer, Gottingen. H. Ganshirt, Heidelberg P. Vogel, Heidelberg Beirat H.Caspers, Munster H.Hager, GieBen M.Mumenthaler, Bern A. Pentschew, Baltimore G. Pilleri, Bern G. Quadbeck, Heidelberg F. Seitelberger, Wien. W. Tonnis, KOln

2 Erlo Esslen The Acute Facial Palsies Investigations on the Localization and Pathogenesis of Meato-Labyrinthine Facial Palsies With a Foreword by U. Fisch, Zurich With 127 Figures Springer-Verlag Berlin Heidelberg New York 1977

3 Privatdozent Erlo Esslen, M.D. Division of Neurology, Kantonsspital Aarau, Switzerland The investigations were performed at the University Hospital of Neurology, Zurich, Switzerland. ISBN-13: e-isbn-13: DOl: / Library of Congress Cataloging in Publication Data. Esslen, Erlo. The acute facial palsies. (Schriftenreihe Neurologie). Bibliograpby: p. Includes index.!. Paralysis, Facial-Etiology. 2. Facial nerve-diseases-diagnosis. 3. Facial nerve-surgery. 4. EIectrodiagnosis. I. Title. II. Series. [DNLM: I. Facial paralysis-etiology. 2. Facial nerve-pathology. 3. Constriction, Pathologic-Complications. 4. Herpes zoster-complications. 5. Labyrinth. 6. Petrous bone. WISC344 Bd. 18/WL330 E78a]. RC418.E ' This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. Under 54 of the German Copyright Law, where copies are made for other than private use, a fee is payable to the publisher, the amount of the fee to be determined by agreement with the publisher. by Springer-Verlag Berlin Heidelberg Softcover reprint ofthe hardcover 1st edition 1977 The use of registered namens, trademarks, etc., in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Offset printing and bookbinding: Briihlsche UniversiHitsdruckerei, Lahn-GieBen 2123/

4 Foreword v I have been privileged to work with Dr. Esslen for more than ten years and to have witnessed how surgical progress combined with accurate clinical and electrophysiological investigations have revolutionized the diagnostic and therapeutic approach to the paralysed face. The long journey ofthe VIIth nerve through the temporal bone has been considered for years responsible for the particular liability of this nerve to acute palsies. The disappointing results obtained with surgical decompression confined of necessity to the mastoid and tympanic segments of the fallopian canalled us in the sixties to apply modern otoneurosurgical techniques in order to achieve total exposure of the intratemporal course of the facial nerve. At that time Esslen started to record with surface electrodes the compound action potential evoked by maximal percutaneous stimulation in representative areas of the facial muscles. With this method, called electroneuronography, exact determination ot the percentage of degenerated nerve fibers could be achieved in the early stages ofthe palsy. Precise electroneuronographic criteria for the selection of patients requiring surgery in order possibly to improve the outcome of their disfiguring paralysis were worked out. At surgery d ect stimulation of the totally exposed intratemporal portion of the facial nerve was used for the first time in combination with electroneurography in order to determine objectively the degree of the lesion. In contrast to what has been believed for years the pathology related with acute facial palsy has been found to be situated in the majority of the cases at the entrance and not toward the exit of the fallopian canal. Although further studies are necessary to establish without question the value of timely surgery, the present monograph establishes without doubt that, in order to be effective, it has to be performed in the most hidden labyrinthine and meatal portions of the facial nerve. In any case, the electroneuronographic criteria indicate that less than 5% of the patients can be considered as candidates for surgery. In view of the localisation of pathology familiarity with the most modern otoneurosurgical procedure is an essential prerequisite for a successful operation. The work of Esslen has deeply extended our knowledge on the natural history of the most common acute facial palsies and has established valid criteria for surgical indications. There is no doubt that Esslen's monograph will remain for years to come the basis for a logical therapeutic approach to the acutely paralysed face. Zurich, March 1977 U. Fisch

5 VII Preface This treatise is the result of 10 years of close cooperation between neurologist and otologist. The cooperation began with the question of how the results of "decompression" of facial nerve could be assessed. This intervention had then for more than 10 years been part of the repertoire of otologic operations. It implies the opening of the tympanic or mastoidal section of the fallopian canal and slitting of the epineurium. The indication for this intervention was, however, rather vague and opinions on the most appropriate time varied considerably among otologic surgeons. We tried to answer the question of the usefulness of decompression of facial nerve by combined clinical and electromyographic investigations. Several years of work on this revealed that decompression of the facial nerve did not improve the prognosis. This was confirmed some time later by other investigators (Naumann et ai., 1968; Adour and Swanson, 1971). This disappointing result was enhanced by the fact that the exploration of the facial nerve after opening of its canal did not show any impressive alteration of nerve tissue suggesting that one had found the site of the essential pathogenetic processes causing palsy. For both of these reasons, the ineffectiveness of decompression as well as the vanishing evidence of the underlying pathogenetic concept, this intervention was given up in 1967 in Zurich. The new technique of transtemporal opening of the internal auditory channel and of the fallopian canal, introduced in Zurich in 1968, completely changed the situation. The first probatory openings of the internal auditory channel in cases of herpes zoster oticus, later of Bell's palsy as well, revealed an enormous edema and hemorrhage, infarction ofthe facial nerve just before the entrance to the fallopian canal, and a severe strangulation of the nerve at the transition of the relatively wide fundus of the internal meatus acusticus and the much narrower canal of the facial nerve. The grossly bulging facial nerve could not enter its proper canal without a two to threefold reduction of its diameter. These observations induced new concepts about the localization and the essential pathogenetic factors involved in different types of acute facial palsies. Considering the severe morphologic alteration of the facial nerve at the entrance to its canal it was assumed that this was also the site of functional disturbance. In order to test this assumption, the facial nerve was electrically stimulated along its whole course through the petrosal bone after opening of the internal auditory channel and the fallopian canal and the evoked compound muscle action potential of facial muscles was recorded. The results of these investigations and the integration of morphologic and electrophysiologic findings form part of the first section of the monograph. In relation to the new operative technique and the outlook of a very much improved method of decompression of the facial nerve, an ever growing need for more reliable methods of pre- and postoperative evaluation and documentation of the functional and morphologic state of the facial nerve became obvious. All electrodiagnostic

6 VIII methods hitherto applied did not allow the establishment of a profile of the day-to-day alterations of the facial nerve and did not make possible a close follow-up of the natural history of facial palsies of different genesis. The application of an electroneurographic method adapted especially for this purpose has led to the discovery of "rules" of this natural history. The knowledge of these rules has created a new basis for earlier and more reliable prognoses in acute facial palsies. Furthermore it has established an essential similarity of natural history in facial palsies of different etiology. I am indebted to Prof. Baumgartner, Head of the University Hospital of Neurology, Zurich, for kind support of this work. Zurich, March 1977 E. Esslen

7 IX Contents Introduction Anatomical Considerations 3 Course of the Facial Nerve in the Petrosal Bone Composition and Fiber Spectrum of Facial Nerve 7 Intraneural Topography of Facial Nerve Evaluation of Present Views on Etiology and Pathogenesis of Acute Facial Nerve Palsy Idiopathic Facial Palsy (Bell's Palsy) 8 Herpes Oticus with Concomitant Facial Palsy (Ramsey Hunt Syndrome) 12 Bilateral Facial Palsies Investigations, Part I: Intratemporal Stimulation of Facial Nerve for Localization of Conduction Block in Idiopathic Facial Palsy, Herpes Oticus, and Melkersson-Rosenthal Syndrome Operative Access to the Internal Auditory Channel and Other Intrapetrosal Sections of the Facial Nerve, 17 Intraoperative Stimulation and Recording Technique 17 Results of Intraoperative Stimulation of Facial Nerve in the Internal Acoustic Meatus and Facial Canal. Aspect of the Facial Nerve Under the Operative Microscope 18 Findings in Favor of a Revised Conception of the Relevant Pathogenetic Factors in Acute Facial Palsies 25 Histopathologic Findings in Idiopathic Facial Palsy 25 Histopathologic Findings in Herpes Oticus 29 Integration of Morphologic and Electrophysiologic Findings 35 Investigations, Part II: Electrophysiologic Investigations on the Natural History of Acute Facial Palsies 39 Electrodiagnosis of the Facial Nerve General Considerations Special Problems of Electrodiagnosis of the Facial Nerve Electrodiagnostic Methods Hitherto Applied for Diagnosis in Facial Palsy A New Method for the Determination of the Degree of Degeneration of Facial Nerve 45 Remarks on Some Clinical Features ofacute Facial Palsies 50 Implications oftopical Diagnosis 51 Case Reports Discussion ofthe Graphical Presentation of Results 55

8 x Results. Idiopathic Facial Palsy (Groups 1-9). General Principles that Emerge from the Histories of Idiopathic Facial Palsy. 1. Nerve Fiber Degeneration. 2. Conduction Block and the Beginning of its Recovery. 3. Latency. 4. Completion of Recovery from Conduction Block. 5. Degree ofnerve Regeneration. 6. Degree of Functional Recovery. 7. Age. Herpes Oticus (Groups I and 2). Principles of Disease Evolution in Facial Palsy Associated with Herpes Oticus. Bilateral Facial Palsies: Case Reports. Bilateral Facial Palsies: Principles of Evolution. Acute Facial Palsies of Different Etiologies. Facial Palsies in Petrosal Bone Fractures. Prognosis ofacute Facial Palsies. Operation in Acute Facial Palsy: Transtemporal Decompression. Evolution of Operated Cases. Indications for Transtemporal Decompression of the Facial Nerve. On Drug Therapy of Idiopathic Facial Palsy Summary 117 References 119 Cases Author's Postscript 164