Outcomes in vestibular schwannoma treated with primary microsurgery: Clinical landscape.

[BACKGROUND] Vestibular schwannoma (VS) is the most common tumour of the cerebellopontine angle. Owing to complex anatomy and high rates of morbidity, surgical management of large tumours is challenging. We seek to explore the clinical landscape of VS to identify predictors of outcome and help guide surgical decision making.

[METHODS] We retrospectively reviewed charts of patients who underwent primary surgery for VS between 2005 and 2020 at a quaternary referral center in Toronto, Canada. Mined data includes patient demographics, clinical presentation, radiological features, and treatment details. Regression modelling was used to identify predictors of tumour control, postoperative morbidity, and correlates of progression free survival (PFS).

[RESULTS] Two hundred and five tumours with sufficient data were included in our study. Syndromic NF2, large tumours (>3cm), subtotal resection (vs gross total resection), presence of edema on preoperative MRI, and preoperative trigeminal symptoms were all predictors of postoperative progression/need for further treatment; the latter four were also associated with shorter progression free survival. Extent of resection (EOR), tumour size, and Koos grade were independently predictive of postoperative progression/secondary intervention in multivariate models; however, only EOR was independently predictive of progression-free survival. EOR, tumour size, and patient age are each independently predictive of facial nerve outcome.

[CONCLUSIONS] We comprehensively explore the clinical landscape of surgically treated vestibular schwannoma and highlight important outcome predictors and disease subgroups. This may have important implications in risk stratifying these challenging cases.