Efficacy of a Quantitative Intra-Operative Facial Nerve Continuous Monitoring System for Functional Preservation Following Intratemporal Facial Nerve Schwannoma Resection.

Objective: Preservation of the facial nerve is critical in surgery for facial nerve schwannoma. Intra-operative monitoring systems typically assess facial nerve function by delivering intermittent electrical stimulation through electrodes; however, this approach cannot effectively achieve continuous stimulation and quantitative assessment. This study aimed to assess the efficacy of a quantitative intra-operative facial nerve continuous monitoring system for preserving post-operative facial nerve function. Methods: Ten patients who underwent continuous nerve monitoring using this system during surgery for facial nerve schwannoma were included. Clinical data, electrode placement sites, and pre- and postoperative facial nerve function assessed using the House-Brackmann grading system were retrospectively analyzed. In patients with conductive hearing loss, postoperative hearing outcomes were also analyzed. Results: Facial nerve function was preserved in all patients, except for one patient who experienced transient postoperative functional deterioration. In several cases, conductive hearing loss improved following schwannoma resection. Conclusion: Continuous and quantitative monitoring of facial nerve function is a reliable intraoperative evaluation that may help prevent unexpected facial nerve injury. This system represents a valuable tool for application in facial nerve schwannoma surgeries. Level of Evidence: Level 4.