An Investigation Into Whether the Facial Nerve and Auditory Nerve can be Protected by Removal of the Posterior Wall of the Internal Auditory Canal Under 30 Neuroendoscopy During Vestibular Schwannoma Surgery

The aim of this study was to evaluate the surgical technique of microresection of vestibular schwannoma by removing the posterior wall of the internal auditory canal (IAC) under neuroelectrophysiological monitoring and 30 degrees neuroendoscopy, with respect to the protection of facial and auditory nerve function. Forty-five cases of microscopic resection of auditory neuromas were performed through a posterior approach to the inferior occipital sigmoid sinus using a 30 degrees neuroendoscope to assist in the removal of the posterior wall of the IAC during surgery. Patients underwent cranial enhancement magnetic resonance imaging examination and functional assessment of the facial and auditory nerves before and after surgery, and clinical data were collected for retrospective analysis. All tumors were removed in 41 patients, and most of the tumors were removed in 4 patients. The facial nerve was anatomically preserved in 43 patients (95.6%), and the percentage of facial nerve function preservation (House-Brackmann grade I-II) was 84.4%. Forty patients (88.9%) had anatomical preservation of the auditory nerve, with a 66.7% functional preservation rate. At 3 to 39 months of follow-up, 45 patients were reviewed with 3.0 T-enhanced magnetic resonance imaging, and no tumor recurrence was observed in any of the patients. Microscopic resection of auditory neuroma through the posterior approach of the inferior occipital sigmoid sinus with intraoperative use of 30 degrees neuroendoscopic assistance to abrade the posterior wall of the IAC can eliminate dead space in certain anatomical areas during surgery and minimize surgical damage to the facial and auditory nerves, which is the basis for preservation of facial and auditory nerve function.