Radiosurgery for Facial Nerve Schwannoma: A Systematic Review

Objective: To systematically review the existent literature on radiosurgery for treatment of sporadic facial nerve schwannomas (FNS). Databases reviewed: PubMed, SCOPUS, EMBASE, and Web of Science databases. Methods: Systematic review was performed per PRISMA criteria of studies published from 1990 through 2024 on patients diagnosed with sporadic FNS who were treated with radiosurgery. Outcomes included change in facial nerve function, change in hearing class, and radiosurgical treatment failure defined by need for reintervention. Study quality was assessed using the LEGENDS rubric for mixed modality studies. Results: In total, 35 studies encompassing 364 patients were included for data abstraction. Gamma Knife was the most common modality reported. Longitudinal patient-level data on facial nerve function were available for 101 patients, with 8% of patients experiencing worsening facial nerve function and 92% of patients having either stable nerve function or improvement in facial nerve function following treatment over a median follow-up of 36 months. Longitudinal patient-level hearing data were available for 53 patients, including 35 patients with serviceable hearing (AAO-HNS class A or B) at baseline; only 2 patients developed nonserviceable hearing (AAO-HNS class C or D) following treatment over a median follow-up of 36 months. Clinical tumor control data were available for 295 patients, of whom 11 required salvage treatment over a mean follow-up of 49 months. Conclusions: This systematic review demonstrates a relatively low risk of worsening facial nerve function and a high rate of clinical tumor control following radiosurgery for sporadic FNS.