Early post-operative hydrocephalus following retrosigmoid vestibular schwannoma resection: Incidence, clinical patterns, and outcomes.

Introduction: Early post-operative hydrocephalus after retrosigmoid vestibular schwannoma (VS) resection is recognised but insufficiently characterised. Research question: What are the incidence, clinical phenotypes, peri-operative predictors, and outcomes of early post-operative hydrocephalus? Material and methods: We retrospectively reviewed 116 consecutive adults who underwent primary retrosigmoid VS removal between 2020 and 2024. Pre-, intra-, and early post-operative variables were correlated with symptomatic hydrocephalus, defined as ventriculomegaly plus neurological decline within four post-operative days. Management, length of stay (LOS), and late CSF-diversion requirements were analysed. Results: Symptomatic hydrocephalus occurred in eight patients (6.9 %) and required external ventricular drainage (EVD) in six (5.2 %). Two reproducible phenotypes were observed: an acute course (n = 2) with abrupt Glasgow Coma Scale (GCS) < 12, driven by tumour-bed hematoma or fulminant cerebellar edema; EVD was maintained for 11-14 days, one patient died, the other needed a ventriculoperitoneal shunt; a mild course (n = 6) with GCS 13-14 and ipsilateral cerebellar edema; four patients required 5-day EVD, all recovered fully. Tumour-bed hematoma was the only significant predictor ( Discussion and conclusion: Early post-operative hydrocephalus complicates 5 % of retrosigmoid VS resections and manifests as either a life-threatening acute form or a mild form. Vigilant early MRI/CT and a stepwise escalation from steroids to selective EVD achieve favourable outcomes; preventing tumour-bed hematoma is the principal modifiable risk factor.