Age, preoperative tumor volume and widening of the internal acoustic meatus are independent factors associated with poor preoperative hearing in vestibular schwannoma patients – results of a single-center retrospective analysis

Abstract Background: Preoperative hearing function shows wide variations among patients diagnosed with vestibular schwannoma. In addition to the obvious role of tumor size other factors that influence hearing function are frequently discussed. Methods: We analyzed clinical factors, imaging data and the expression of the proliferation marker MIB1 as potential influencing factors on the preoperative hearing function in a retrospective cohort of 523 primary sporadic vestibular schwannomas. The results of the preoperative audiometry were quantified using the Gardner-Robertson Score. Uni- and multivariate analyses were performed. Results: Serviceable hearing (Gardner-Robertson class 1 or 2) was documented in 391 patients (74.8%). Factors associated with non-serviceable hearing (Gardner-Robertson class 3–5) were patients of older age (p < 0.0001), larger preoperative tumor volume (p = 0.0013) and widening of the internal acoustic meatus compared to the healthy side (p = 0.0353). Gender and the expression of the proliferation marker MIB1 were no significant factors. In the multivariate nominal logistic regression older age (OR 27.60 (CI 9.17–87.18), p < 0.0001), larger preoperative tumor volume (OR 20.20 (CI 3.43–128.58), p = 0.0011) and widening of the internal acoustic canal (OR 7.86 (CI 1.77–35.46), p = 0.0079) remained independent factors associated with non-serviceable hearing. Conclusions. Widening of the internal acoustic canal is an independent factor for non-serviceable preoperative hearing in vestibular schwannoma patients together with older age and larger preoperative tumor volume.