Preservation of Hearing in Vestibular Schwannoma Surgery

Introduction: Besides facial nerve function, patients claim hearing to be of great subjective importance especially in the case of “the last hearing ear.” The influence of the microsurgical technique under neurophysiological monitoring was the focus of this study. Methods: In a consecutive series of 400 patients with vestibular schwannomas, 274 presented with some residual hearing. The goal of hearing preservation was indicated depending on the patient's individual clinical signs, wishes, and needs. Also in case of only moderate hearing rest, but the last hearing ear, an attempt for preservation was undertaken. In these cases, double or triple modality monitoring of auditory brainstem responses (ABR) was performed by conventional ABR and near field techniques at the cochlea and brainstem. Results: Independent of tumor size and preoperative hearing function, overall preservation rate was 30%, but increased to 47% in case of multimodality ABR control. This provided a useful support especially in phases with increased artifacts and therefore enabled preservation also in difficult cases. Conclusion: Functional nerve preservation is an important factor in patients' subjective outcome after VS treatment. The high vulnerability of the auditory pathway and of ABR may, in part, be overcome by the multimodality monitoring control, which provides more reliable and faster feedback to the surgeon.