Salvage Microsurgery for Vestibular Schwannoma after failed Stereotactic Radiosurgery: A Multicentric Retrospective Study

Purpose This study aimed to evaluate the clinical indications, technical characteristics, and outcomes of salvage microsurgery in patients with sporadic vestibular schwannomas (VS) primarily treated with Stereotactic radiosurgery (SRS). Methods This retrospective multicenter study included 28 patients who underwent salvage microsurgery between 2012 and 2022 at six European tertiary referral centers. Data on demographics, tumor characteristics, surgical approach, extent of resection, and functional outcomes were collected, with a focus on facial nerve preservation and postoperative complications. Results Tumor progression, with or without symptoms, was the predominant indication for surgery (60.7% of cases). The median interval between SRS and surgery was 42 months (range 24–120). Intraoperative findings revealed altered tumor consistency and limited mobility due to arachnoid adhesions or fibrosis in 19 patients (67.9%). Gross total resection was achieved in 53.6% of the cases, with near-total resection in 28.6% of the cases. No patient retained serviceable hearing, but postoperative facial nerve function improved over time, with 62.5% achieving House-Brackmann grade I at 12 months. The complication rate was 10.7%, with no procedure-related mortality observed. Conclusion Salvage microsurgery represents a viable and safe therapeutic option for managing VS following failed SRS. The timing of surgical intervention may be critical to optimizing outcomes. Favorable results in this cohort may reflect both the high-volume expertise of participating centers and a shared institutional preference for delayed intervention. Although technically more demanding than primary resection, acceptable morbidity and good functional outcomes can be achieved when function-preserving strategies are employed.