Hearing preservation in acoustic neuroma surgery

Abstract

Hearing conservation in acoustic tumour surgery remains controversial. There have been few previous reports in the British literature. The senior author has managed 24 patients by retrosigmoid surgery with the intention of preserving hearing during the last 9 years. The clinical features, surgical technique and results are discussed with respect to pre-operative selection criteria, and post-operative quality of hearing. Hearing preservation has been achieved in 11 (78.6%) of 14 patients with small or intracanalicular tumours and a mean minimum auditory threshold of 35 dB and 70% speech discrimination, the majority (81.8%) above the 50 dB/50% level. Tumour filing the fundus of the internal auditory canal was found to be a significant adverse prognostic factor as regards successful hearing preservation. Tumour excision was complete in all patients. Nearly 90% of patients had normal facial function, and the remaining 10% grade II function. Associated morbidity was minimal. It is suggested that the potential for hearing conservation should be considered as a factor in the management of patients with small acoustic neuromas.

Fortnightly Review: Management of acoustic neuroma

“…Intraoperative monitoring of the electrical function of the cochlea and auditory brain stem is possible (although difficult) and is practised by some groups 10. Whether widespread acceptance of this technique occurs will depend on the usefulness of the residual hearing after such surgery, and there is much debate as to what constitutes useful residual hearing,11 but in those few people with absent or poor hearing in the other ear such techniques may become mandatory. The development of brain stem auditory implants, whereby electrodes are placed on the brain stem cochlear nuclei (which conveniently lie on the surface of the brain stem), might mean that even though the cochlear nerve is damaged “hearing” can be preserved.…”

Hearing Preservation in Acoustic Neuroma Surgery: The Impact of Different Patient Selection Criteria

“…The importance of this finding is illustrated by the following example. Applying the selection criteria proposed by Brookes and Woo 11 in our population would lead to 8 patients being considered suitable for hearing preservation surgery and 72 being unsuitable, whereas using the criteria of Atlas et al 10 would lead to 45 patients being suitable and 35 being unsuitable for hearing preservation surgery. If the first criteria are, in fact, too conservative and the second ones are realistic, in our population of 80 patients, 37 could have missed their chance of preserving hearing.…”

“…Six studies were found to fulfill the criteria. 8–13 The selection criteria for hearing preservation surgery used in these studies are shown in Table I.…”

Die Chirurgie des Kleinhirnbr�ckenwinkels

“…In gewissen Os temporale ist es aufgrund anatomischer Konfiguration des Labyrinthes und des inneren Gehörganges jedoch unmöglich, den lateralen Tumoranteil darzustellen, ohne das Labyrinth zu eröffnen [39]. Dieser teilweise Mangel, die Tumoren im lateralen Anteil des inneren Gehörganges zu erreichen und damit unter Sicht zu resezieren, könnte einerseits die Rezidivhäufigkeit erhöhen [60] und andererseits zu Läsionen des Kochlearis führen [61,62] und stellt somit den hauptsächlichen Nachteil dieses Zugangsweges dar (Tabelle 8).…”

“…Zudem besteht eine Gefahr der Verletzung des Ductus oder Saccus endolymphaticus [62]. Dem stehen aber gravierende Vorteile gegenüber, indem der retrosigmoidale Zugang die beste Mög-lichkeit zur Hörerhaltung aller Zugangswege darstellt, mit für die anderen Zugänge mindestens vergleichbaren Fazialiserhaltungswerten, auch wenn der Fazialis meist auf der anterioren Seite der Tumorkapsel adhärent ist und deshalb nur sehr spät im Laufe der Operation visuell erfasst werden kann.…”