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

## TL;DR

This study finds that 5% of patients who undergo a specific brain tumor surgery develop early hydrocephalus, with two distinct clinical patterns and outcomes.

## Contribution

The paper identifies two reproducible clinical phenotypes of early post-operative hydrocephalus and highlights tumour-bed hematoma as the sole significant predictor.

## Key findings

- Early post-operative hydrocephalus occurred in 6.9% of patients and required external ventricular drainage in 5.2%.
- Two distinct clinical phenotypes were observed: an acute life-threatening form and a milder form with full recovery.
- Tumour-bed hematoma was the only significant predictor of hydrocephalus, while tumour size, age, and cystic components were not.

## Abstract

Early post-operative hydrocephalus after retrosigmoid vestibular schwannoma (VS) resection is recognised but insufficiently characterised.

What are the incidence, clinical phenotypes, peri-operative predictors, and outcomes of early post-operative hydrocephalus?

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.

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 (p = 0.0018); demographics, tumour size/volume, cystic component, and extent of resection were neutral. EVD placement prolonged median LOS (20 vs 13 days, p = 0.001).

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.

•Hydrocephalus in 5 % of retrosigmoid VS cases, always within 4 days post-op.•Two forms: mild (GCS ≥13) heals with steroids/EVD; acute (GCS <12) riskier.•Tumour-bed hematoma was the sole predictor; size, cysts, age were neutral.•Early MRI/CT, drugs, and selective EVD kept shunt rates low and drains safe.•42 % had silent ventriculomegaly, so action must follow symptoms, not ventricle size.

Hydrocephalus in 5 % of retrosigmoid VS cases, always within 4 days post-op.

•Two forms: mild (GCS ≥13) heals with steroids/EVD; acute (GCS <12) riskier.

•Tumour-bed hematoma was the sole predictor; size, cysts, age were neutral.

•Early MRI/CT, drugs, and selective EVD kept shunt rates low and drains safe.

•42 % had silent ventriculomegaly, so action must follow symptoms, not ventricle size.