Title: Risk factors for postoperative meningitis after microsurgery for vestibular schwannoma

OBJECTIVE: Meningitis after microsurgery for vestibular schwannoma (VS) is a severe complication and result in high morbidity. But few studies have focused on meningitis after VS surgery alone. The purpose of this study was to identify the risk factors for meningitis after VS surgery. METHODS: We undertook a retrospective analysis of all VS patients, who underwent microsurgery of VS and at least live for 7 days after surgery, between 1st June 2015 and 30st November 2018 at West China Hospital of Sichuan University. Univariate and multivariate analyses were performed to identify the risk factors for postoperative meningitis (POM). RESULTS: We collected 410 patients, 27 of whom had POM. Through univariate analysis, hydrocephalus (p=0. 018), Koos grade IV?p=0.04?, The operative duration (> 3 hours p=0.03) and intraoperative bleeding volume (≥400ml p=0. 02) were significantly correlated to POM. Multivariate analysis showed that Koos grade IV (p=0.04; OR=3.19; 95% CI 1.032-3.190), operation duration (> 3 hours p=0.03 OR= 7.927; 95% CI 1.043-60.265), and intraoperative bleeding volume (≥ 400ml p=0.02; OR=2.551; 95% CI 1.112-5.850) are the independent influencing factors of POM. CONCLUSIONS: Koos grade IV, the duration of operation, and the amount of bleeding were identified as independent risk factors for POM after microsurgery of VS. POM caused a prolonged hospital stay.