Functional Outcome After Simultaneous Vestibular Schwannoma Resection and Cochlear Implantation With Intraoperative Cochlear Nerve Monitoring

Abstract

Objective: Electrically evoked auditory brainstem response audiometry has emerged as a suitable option to intraoperatively assess cochlear nerve function during vestibular schwannoma resection. This study aimed to analyze the functional outcome and implant usage of patients with preserved auditory nerve responses after simultaneous translabyrinthine schwannoma resection and cochlear implantation.

Study design: Prospective study.

Setting: Tertiary referral center.

Methods: Patients with unilateral sporadic vestibular schwannoma underwent translabyrinthine tumor resection. Intraoperatively, electrically evoked auditory brainstem response audiometry was performed before and after tumor removal. Cochlear implantation was carried out if positive responses were detected after tumor removal indicating cochlear nerve function. Postoperatively, patients were biannually followed-up to assess aided sound field audiometry and word recognition as well as implant usage.

Results: Overall, 26 patients with vestibular schwannoma underwent translabyrinthine schwannoma resection. Out of these patients, 15 had positive cochlear nerve responses after tumor removal and concurrently received a cochlear implant. In 13 patients with histologically confirmed vestibular schwannoma, hearing improved by 23.7 ± 33.2 decibels and word recognition by 25.0 ± 42.4% over a mean follow-up period of 18 months. Overall, 12 included patients were regular cochlear implant users.

Conclusion: Patients with vestibular schwannoma can benefit substantially from cochlear implantation. Intraoperative assessment of cochlear nerve function using electrically evoked auditory brainstem response audiometry can help to better identify individuals eligible for simultaneous vestibular schwannoma resection and cochlear implantation.

Keywords: acoustic neuroma; cochlear implantation; one-sided surgery; speech perception; translabyrinthine surgery; treatment; vestibular schwannoma; word recognition.