Hearing Restoration During Vestibular Schwannoma Surgery With Transcanal Approach: Anatomical and Functional Preliminary Report.

Abstract

Hearing restoration has always been a dream in vestibular schwannoma (VS) surgery. The aim of this study is to describe an endoscopic assisted transcanal retrocochlear approach to the internal auditory canal (IAC) with total removal of the VS; simultaneously we assessed the anatomical and functional aspects of hearing restoration with cochlear implant (CI). A retrospective case series. Tertiary referral center. Six patients affected by VS involving the fundus of the IAC (Koos stage I-II) were included in this study. The patients already demonstrated symptoms of IAC involvement by the neuroma, with severe to profound hearing loss. Transcanal microscopic, endoscopic assisted, approach was chosen for total tumor removal. Preoperative and intraoperative electrophysiological monitoring was performed using electrically evoked auditory brainstem responses (EABR) to evaluate preservation of cochlear function. A retrospective evaluation of electrophysiological data collected during surgeries has been conducted; clinical outcomes, surgical complications, and postoperative radiological evaluations were also considered. Total tumor removal was achieved in all patients with no major complications. One patient showed temporary facial palsy (HB stage II). We were able to preserve cochlear function in five out of six patients. In those patients intraoperative monitoring with EABR was performed after tumor removal with good responses. Transcanal retrocochlear approach for VS removal allows preservation of cochlea and cochlear nerve function. This is the first step towards developing an effective surgical technique for VS removal and hearing rehabilitation with CI.