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.

Cochlear Implantation in Neurofibromatosis Type 2‐Related Schwannomatosis: Long‐Term Hearing Outcomes

“…This technique has a high sensitivity for CI use and its performance is good, with 87% of patients with positive eABR having good speech intelligibility scores with their CI at 18 months. However, negative eABR results should not dissuade the surgeon from performing cochlear implantation 31,54 …”

“…However, negative eABR results should not dissuade the surgeon from performing cochlear implantation. 31,54 The maintenance of CI performance over time is also a significant concern for NF2 patients, and only a few studies have reported long-term follow-up data. Smith et al indicated a 13% decline in the ability to understand speech over a mean follow-up period of 4 years.…”