A case series shows independent vestibular labyrinthine function after major surgical trauma to the human cochlea

Abstract

Background The receptors for hearing and balance are housed together in the labyrinth of the inner ear and share the same fluids. Surgical damage to either receptor system was widely believed to cause certain permanent loss of the receptor function of the other. That principle, however, has been called into question because there have been anecdotal reports in individual patients of at least partial preservation of cochlear function after major surgical damage to the vestibular division and vice versa. Methods We performed specific objective vestibular function tests before and after surgical trauma (partial or subtotal cochlear removal) for treatment of intracochlear tumors in 27 consecutive patients in a tertiary referral center. Vestibular function was assessed by calorics (low-frequency response of the lateral semicircular canal), vestibulo-ocular reflex by video head impulse test (vHIT) of the three semicircular canals, cervical and ocular vestibular evoked myogenic potentials (cVEMP, saccule and oVEMP, utricle). Preoperative and postoperative distributions were compared with paired t-tests. Results Here we show that there was no significant difference between pre- and post-operative measures for all tests of the five vestibular organs, and that after major surgical cochlear trauma, the vestibular receptors continue to function independently. Conclusions These surprising observations have important implications for our understanding of the function and the surgery of the peripheral auditory and vestibular system in general and open up new possibilities for the development, construction and evaluation of neural interfaces for electrical or optical stimulation of the peripheral auditory and vestibular nervous system.

Unilateral Multifocal Inner Ear and Internal Auditory Canal or Cerebellopontine Angle Cochleovestibular Schwannomas—Genetic Analysis and Management by Surgical Resection and Cochlear Implantation

“…Outcome in speech audiometry in the two patients (WRS 65 55% and 60%) was not as good as results from our group for patients with solely intracochlear schwannomas (mean 72.5%) (22). When comparing speech audiometry results for the available and internationally comparable outcome parameters, the outcomes were similar or even better than those reported for CI after surgery, radiation, or observation of vestibular schwannomas in the IAC and/or CPA (26).…”

Das vestibuläre Labyrinth ist robuster als bisher gedacht – Erkenntnisse nach chirurgischer Entfernung intracochleärer Schwannome

“…Bei den meisten Patienten zeigte sich postoperativ eine normale Otolithenfunktion (Sacculus und Utrikulus). Die Hörrehabilitation mittels Cochleaimplantat (CI) war erfolgreich, und das Einsilberverstehen bei einem Sprachpegel von 65 dB SPL verbesserte sich innerhalb des Beobachtungszeitraumes von zwölf Monaten kontinuierlich [ 1 ].…”

“…Vor Kurzem konnten wir in einer großen Fallserie zeigen, dass nach relevantem chirurgischem Trauma der Cochlea im Rahmen der operativen Entfernung intracochleärer Schwannome die vestibulären Rezeptoren weiter normal funktionieren. Dies wurde mithilfe spezifischer, objektiver Funktionstests für alle fünf Gleichgewichtrezeptoren vor und nach der Operation nachgewiesen [ 1 ].…”

The vestibular labyrinth is more robust than previously thought—Lessons from surgical removal of intracochlear schwannoma

“…Successful hearing rehabilitation with the cochlear implant and continuous improvement over 12 months was shown by word recognition at normal speech level (65 dB SPL, [ 1 ]).…”

“…Recently, we showed in a large case series that after major trauma to the cochlea for surgical removal of intracochlear schwannoma, the vestibular receptors continue to function normally. This was demonstrated by specific, objective function tests for each of the peripheral vestibular receptors before and after surgery [ 1 ].…”