Optimizing Location of Subdermal Recording Electrodes for Intraoperative Facial Nerve Monitoring

Objective The purpose of this study is to determine if different facial muscle groups demonstrate different responses to facial nerve stimulation, the results of which could potentially improve intraoperative facial nerve monitoring (IOFNM). Methods IOFNM data were prospectively collected from patients undergoing cochlear implantation. At different stages of nerve exposure, three sites were stimulated using a monopolar pulse. Peak electromyography (EMG) amplitude (μV) in four muscle groups innervated by four different branches of the facial nerve (frontalis‐temporal, inferior orbicularis oculi‐zygomatic, superior oribularis oris‐buccal, and mentalis‐marginal mandibular) were recorded. Results A total of 279 peak EMG amplitudes were recorded in 93 patients. At all three stimulating sites, the zygomatic branch mean peak EMG amplitudes were statistically greater than those of the temporal, buccal, and marginal mandibular branches (P