Comparative analysis of stereotactic radiosurgery and microsurgery for vestibular schwannoma: a clinical and radiological evaluation

PURPOSE: To compare radiographic and clinical outcomes of vestibular schwannoma management using stereotactic radiosurgery (SRS) and microsurgical resection, with emphasis on paired pre- and post-treatment changes in tumor size and patient outcomes. METHODS: A retrospective review was conducted of 87 patients treated for vestibular schwannoma between 2013 and 2024 at a single tertiary center. Demographic, clinical, and radiographic variables, including hearing loss, facial weakness, brainstem compression, tumor area, and Koos grade, were analyzed. Tumor area was determined from radiology reports and compared using nonparametric statistical tests, with significance defined as p < 0.05. RESULTS: Microsurgery achieved a median 76% reduction in tumor area, while SRS was associated with relative stability or modest growth (+ 5%) (p < 0.001). Post-treatment rates of hearing loss and facial weakness were similar between groups, suggesting that substantial tumor reduction following microsurgery was not associated with increased morbidity in this cohort. Koos grade correlated with both brainstem compression and hearing loss, with higher grades favoring surgical management (p = 0.049). In the Koos IV subset, surgery achieved significant tumor reduction without disproportionate postoperative deficits compared with lower grades. CONCLUSION: Microsurgery provides immediate and substantial tumor reduction without increased morbidity, while SRS maintains radiographic stability with favorable clinical outcomes. These findings underscore the complementary roles of both modalities and support the Koos classification as a practical and reliable framework for treatment selection.