The Association of Vestibular Schwannoma Volume With Facial Nerve Outcomes After Surgical Resection.

OBJECTIVE: To explore the relationship between tumor size and facial nerve outcomes following vestibular schwannoma (VS) resection.

STUDY DESIGN: Single institutional retrospective chart review of all adult patients with untreated sporadic VS who underwent surgical resection from 2008 to 2018 with preoperative magnetic resonance imaging (MRI) and 1 year of follow-up. The primary outcome measure was facial nerve outcome as assessed by the House-Brackmann facial nerve grading system.

RESULTS: One hundred sixty-seven patients, 54.5% female, with a median age of 49 years (20-76 years), were identified who underwent VS resection. Surgical resection was performed by translabyrinthine (76.7%), middle cranial fossa (14.4%), retrosigmoid (7.2%), and transpromontorial (1.8%) approaches. The median tumor diameter and volume were 25.3 mm (range: 4.1-47.1 mm) and 3.17 cm3 (range: 0.01-30.6 cm3 ), respectively. The median follow-up was 24.2 months (range: 12-114.2 months). Gross total resection was performed in 79% of cases, with residual tumor identified on MRI in 17% of cases. For patients with tumors <3 cm3 , 92.7% had grade 1 or 2 facial function after at least 1 year follow-up, compared to 81.2% for those with tumors >3 cm3 (univariate logistic regression OR = 2.9, P = .03). Tumor volume >3 cm3 was predictive of facial weakness on multivariate regression analysis (OR = 7.4, P = .02) when controlling for surgical approach, internal auditory canal extension, anterior extension, age, gender, and extent of resection.

CONCLUSIONS: Tumor volume >3 cm3 is associated with worse facial nerve outcomes 12 months following surgical resection.

LEVEL OF EVIDENCE: IV Laryngoscope, 131:E1328-E1334, 2021.