Hearing Outcomes from Gamma Knife Treatment for Intracanalicular Vestibular Schwannomas with Good Initial Hearing.

Background: The objective of this study was to describe the long-term hearing outcomes of gamma knife treatment for unilateral progressing vestibular schwannomas (VS) presenting with good initial hearing using audiologic data. Methods: A retrospective review was performed between 2010 and 2020 to select patients with progressing unilateral VS and good hearing (AAO-HNS class A) treated with stereotactic gamma knife surgery (GKS). Their audiograms were analyzed along with treatment metrics and patient data. Results: Hearing outcomes with a median follow-up of 5 years post-treatment showed statistically significant loss of serviceable hearing: 34.1% of patients maintained good hearing (AAO-HNS class A), and 56.1% maintained serviceable hearing (AAO-HNS class A and B). Non-hearing outcomes are favorable with excellent tumor control and low facial nerve morbidity. Conclusions: Hearing declines over time in intracanalicular VS treated with GKS, with a significant loss of serviceable hearing after 5 years. The mean cochlear dose and the presence of cochlear aperture obliteration by the tumor are the main statistically significant factors involved in the hearing outcomes.