Video-based system for intraoperative facial nerve monitoring: Comparison with electromyography

Objective: To validate a recently developed intraoperative facial nerve monitoring system that is based on video control of facial movements. Study design: In a single-subject design study, involving 15 otoneurosurgical patients, the relationship between intensity of neural stimulation, facial movements, and electrophysiologic voltage were measured, The analysis was performed by measuring the ipsilateral oral commissure displacement in relation to different levels of current administered to the nerve during surgical procedures. Setting: Electromyography and video system intraoperative facial nerve monitoring. Patients: 15 patients (9 men, 6 women; mean age, 61 yr) undergoing a translabyrinthine approach for removal of acoustic neuroma. Results: Electromyography showed slightly greater sensitivity. With regard to the stimulation-response ratio, facial movement and electromyographic amplitude showed very similar responses. Conclusions: The video system was considered useful in terms of validity and reliability, Furthermore, the authors' surgical experience showed some limitations of electromyography, especially in terms of electrical artifact during cauterization, totally masking the electrophysiologic monitoring.