Initial Hearing Improvement and Longevity of Hearing Restoration in Cochlear Implants after Stereotactic Radiosurgery for Vestibular Schwannomas

Objective: Adhering to the PICOTs framework, the following research question was asked: In patients with VS that underwent SRS and cochlear implantation, were improvements in hearing function observed and what was the short-term and long-term failure rate in these patients?

Data Sources: PubMed/Medline, CINAHL (EBSCOhost), and Web of Science articles without restrictions on publication dates were searched.

Study Selection: Inclusion criteria required that the article was a report, series, or retrospective review with individual case data available. Non-English articles were excluded. Inclusion criteria required that patients were with VS and underwent subsequent SRS and cochlear implantation. Patients receiving microsurgery or SRT on the ipsilateral ear were excluded from this study.

Data Extraction: Included studies were evaluated using full-text evaluation and data on study characteristics (author names, gender), clinical data (syndromic information, SRS modality), hearing outcomes, and device failure were extracted.

Data Synthesis: Means and averages were obtained for all continuous variables. Intervals between CI placement and device failure (OS curve) were approximated with the Kaplan–Meier method. Log-rank testing was used to determine significance. The sample was stratified further by tumor size and neurofibromatosis type II status for subgroup analysis. An α of 0.05 was used for all statistical tests.

Conclusions: The majority patients undergoing CI placement in vestibular schwannoma treated with SRS achieved open-set speech perception (79.2%) or environmental sound awareness (6.8%). There were no significant differences found regarding tumor size or neurofibromatosis type II status on implant survival. Twelve implants (20.3%) failed. Three patterns were associated with failure: (1) immediate-onset failure, (2) initial benefit with delayed failure, and (3) poor tumor control with device explantation. Further prospective research is needed before establishing evidence-based guidelines.

Publication History

Article published online:
01 February 2023