Facial nerve recovery trajectories and predictors after vestibular schwannoma surgery: a single-centre cohort study of 213 patients.

BACKGROUND

After tumour control, facial nerve preservation is a primary objective in vestibular schwannoma surgery. Predicting long-term recovery remains challenging, and the prognostic value of the Koos grade is unclear.

OBJECTIVE

The primary outcome was facial palsy at 12 months (partial or severe). Secondary outcomes included Day 1 function, recovery trajectory, intraoperative signal status, Koos grade, complications and difference in surgical approaches.

METHODS

Retrospective cohort study at Sahlgrenska University Hospital (2006-2024). Two reviewers independently extracted clinical data and assigned blinded Koos grades. Predictors were assessed using multivariable logistic regression.

RESULTS

Of 293 surgically treated patients, 213 with complete follow-up formed the study cohort (retrosigmoid 121, translabyrinthine 92). Sixty-four (30.0%) had any palsy at 12 months: 50 (23.5%) partial and 14 (6.6%) severe. Day 1 facial function dominated all models: severe palsy at Day 1 carried an adjusted odds ratio (OR) of 222.08 (95% CI 26.45-1864.44; Firth-corrected OR 128, 21-762), while partial function had an OR of 8.83 (3.93-19.83). Female sex was independently associated with palsy (OR 2.87, p = 0.013); surgical approach was not (OR 0.77, p = 0.550). Koos grade showed no association (OR 1.19, p = 0.730). Among patients with normal Day 1 function, 90% remained palsy free at 1 year; among those with severe palsy, only 4.5% recovered.

CONCLUSIONS

A single bedside examination on post-operative Day 1 predicts long-term facial nerve outcome more powerfully than any variable tested, including Koos grade; comparison of surgical approaches remained inconclusive owing to era confounding. Three recovery trajectories provide a framework for tailored post-operative management.