Preoperative Radiographic Predictors of Hearing Preservation After Retrosigmoid Resection of Vestibular Schwannomas

Objective To identify preoperative radiographic predictors of hearing preservation (HP) after retrosigmoid resection of vestibular schwannomas (VSs). Study Design Retrospective case series with chart review. Setting Tertiary skull base referral center. Methods Adult patients with VSs <3 cm and word recognition scores (WRSs) >= 50% who underwent retrosigmoid resection and attempted HP between February 2008 and December 2018 were identified. Pure tone average (PTA), WRS, and magnetic resonance imaging radiographic data, including tumor diameter and dimensional extension relative to the internal auditory canal (IAC), were examined. Results A total of 151 patients were included. The average tumor size was 13.8 mm (range, 3-28). Hearing was preserved in 41.7% (n = 63). HP rates were higher for intracanalicular tumors than tumors with cerebellopontine angle (CPA) components (57.6% vs 29.4%, P = .03). On multivariate analysis, maximal tumor diameter (odds ratio [OR], 0.892; P < .001) and preoperative PTA (OR, 0.974; P = .026) predicted HP, while mediolateral tumor diameter predicted postoperative PTA (OR, 1.21; P = .005) and WRS (OR, -1.89; P < .001). For tumors extending into the CPA, younger age (OR, 0.913; P = .012), better preoperative PTA (OR, 0.935; P = .049), smaller posterior tumor extension (OR, 0.862; P = .001), and smaller caudal extension relative to the IAC (OR, 0.844; P = .001) all predicted HP. Conclusion Rates of HP are highest in patients with small intracanalicular VSs and good preoperative hearing. For tumors extending into the CPA, greater posterior and caudal tumor extension relative to the IAC may portend worse hearing outcomes.

Automated summary

Radiographic predictors such as tumor size and extension relative to the internal auditory canal play a significant role in hearing preservation after retrosigmoid resection of vestibular schwannomas. Patients with small intracanalicular tumors and good preoperative hearing have the highest rates of hearing preservation, while tumors extending into the cerebellopontine angle may have worse outcomes if they have greater posterior and caudal extension relative to the internal auditory canal.