Predictors of Volumetric Growth and Auditory Deterioration in Vestibular Schwannomas Followed in a Wait and Scan Policy

Objective: The purpose of this study was to identify factors predicting growth and audiologic deterioration during follow-up (FU) in a wait and scan (W&S) policy of vestibular schwannomas (VSs) using a novel volumetric measuring tool. So far, only consecutive magnetic resonance imaging (MRI) is able to show growth objectively, and growth, combined with hearing function, generally dictates further intervention. Other factors predicting growth or hearing deterioration would be invaluable and might ease clinical decision making. Study Design: Retrospective case study. Setting: Tertiary referral center. Patients: Sixty-three patients diagnosed with VS at Maastricht University Medical Center between 2003 and 2008, with FU data available from 36 patients. Intervention(s): A W&S policy for unilateral VS with sequential contrast-enhanced T1- and T2-weighted MRI and audiograms during FU. Main Outcome Measure(s): 1. Patient and radiologic VS features potentially related to growth and auditory function during a W&S policy. 2. The correlation between increase in VS volume and audiologic deterioration during FU. Results: Labyrinthine hypointensity on T2-weighted magnetic resonance images and complaints of hearing loss at presentation are predictive of a faster deterioration of hearing (p <0.05). Growth during the first FU year predicts further growth. Vestibular schwannoma volume does not correlate with audiologic deterioration significantly. Conclusion: Hypointensity on T2-weighted image of the affected labyrinth will result in a significant faster deterioration of hearing. Hearing loss was more profound, and hearing will deteriorate significantly faster in patients presenting with complaints of hearing loss. Significant growth during the first year of FU predicts further growth during FU. Sequential MRI cannot be substituted by audiologic examinations solely because increase in VS volume does not correlate with audiologic deterioration significantly.