gms | German Medical Science

Objective: The aim of this study is to evaluate the effects of vestibular schwannoma consistency on internal auditory meatus widening, presenting symptoms and MRI-appearance.

Method: We performed a retrospective analysis of 140 consecutive patients presenting with unilateral VS who underwent surgical treatment in our neurosurgical Department. Operative videos were analyzed, and the tumors were classified into soft and hard tumors according to the resactibility with the ultrasonic aspirator. The IAM widening both in tumor and normal sides were measured in preoperative bone-window computed tomography, and the percentage of widening between both sides was calculated. Tumor intensity was assessed on T2WI. Patient reports were retrospectively reviewed, and preoperative findings were documented including facial function, hearing level, tinnitus, and vertigo.

Results: The mean diameter of the IAM opening on the tumor side was 10.16 mm. Widening of the IAM due to presence of the VS occurred in 118 patients (84.3%). The degree of widening of the IAM on the tumor side in relation to the other side ranged from 0.5 to 140.03% (mean 35.47%). Tumor was soft in 91 cases (65%), and hard in 49 cases (35%). The mean diameter of the IAM in cases of soft tumors was 9.8 mm, while in hard tumors the mean diameter was 10.58. Significant correlation was found between tumor consistency and degree of widening of the IAM (P value < 0.0001). No significant correlation was found between tumor intensity (in MRI T2WI) and tumor consistency. A significant correlation was found between tumor consistency and facial function before treatment (P value = 0.016). There was no significant correlation between tumor consistency and other preoperative symptoms or signs. Also, no correlation was found between tumor consistency and tumor extension.

Conclusions: Hard vestibular schwannoma is associated with more widening of the internal auditory meatus and is related to poor facial function before treatment.