Cochlear Implantation With Sporadic Inner Ear Schwannomas: Outcomes in 106 Patients From an International Multi-Institutional Study

Abstract

Objective: To evaluate cochlear implant speech perception among patients with sporadic inner ear schwannoma who underwent ipsilateral implantation.

Study design: Retrospective multi-institutional cohort study.

Setting: Eleven tertiary academic medical centers across Germany, Denmark, and the United States.

Patients: One hundred six patients with sporadic inner ear schwannoma who received an ipsilateral cochlear implant from 2011 to 2022.

Interventions: Ipsilateral cochlear implantation with observation, stereotactic radiosurgery, or microsurgery for tumor management.

Main outcome measures: Monosyllabic speech perception testing scores and rates of open-set speech perception.

Results: Among 106 patients studied, 101 (95%) achieved open-set speech perception with a median of 24 months (interquartile range [IQR] 12-42 mo) of audiometric follow-up. Median ipsilateral monosyllabic speech perception testing achieved was 72% (IQR 54-85%), and median ipsilateral AzBio in quiet was 75% (IQR 46-90%). Most (91 of 106 [86%]) underwent microsurgery for tumor control, with cochlear implantation performed simultaneously in 98% (89 of 91) of these patients. The ability to achieve gross total resection significantly differed by tumor complexity, with 97% of low-complexity tumors, 100% of intermediate complexity, and 0% of high-complexity tumors undergoing gross total resection (p < 0.001). However, among patients managed with microsurgery, there was not a statistically significant difference in post-cochlear implantation monosyllabic speech perception scores across complexity groupings, with median scores of 75 and 70% for patients with tumors of low or intermediate complexity and those with tumors of high complexity, respectively (p = 0.5). Eight of 102 patients (8%) assessed experienced deterioration in cochlear implant performance over time. Among the subset of 39 patients with available MRI to review, the region of surveillance interest could be visualized postoperatively on MRI in all cases.

Conclusions: Open-set speech perception is achieved in most patients with inner ear schwannoma undergoing ipsilateral cochlear implantation. Although cochlear implantation in high-complexity inner ear schwannomas is only possible with incomplete tumor resection, long-term open-set speech perception outcomes are similar to lower-complexity tumors.