Value of the Use of Facial Nerve Monitoring in Otorhinolaryngological Surgeries

Abstract

Background The anatomy of the facial nerve is among the most complex of the cranial nerves. Facial nerve is not just a pure voluntary motor nerve but comprises parasympathetic, general sensory, and special sensory components as well. Facial nerve monitoring is one of the most exciting innovations in neurotologic surgery in the past decade. Objective To determine the effect of intraoperative facial nerve monitoring on postoperative facial nerve function and on operative time. Patients and Methods In general terms, FNM means electrophysiological monitoring. This technique provides for monitoring of facial muscle activity via electromyography (EMG).The EMG is typically recorded with needle electrodes placed in facial nerve muscles. Voluntary activation of the facial nerve in the alert patient as well as intraoperative electrical stimulation or mechanical irritation during surgery generates motor evoked potentials. In this meta-analysis, the included studies are ten in number with total 593 patient (control= 311, IOFNM = 282) Results Comparison of facial nerve monitoring vs. no monitoring as regards incidence of facial nerve dysfunction shows there is no evidence of heterogeneity and statistically significant (p-value <0.01) which indicate that the incidence of FN dysfunction in the monitoring group is lower than the dysfunction in the no monitoring group. Comparison of facial nerve motoring vs. no monitoring as regards operative time shows there is no evidence of heterogeneity. Under the random effect model, the standardized mean difference (SMD) is -0.62 which is statistically significant (p-value <0.01) favoring facial nerve motoring over no monitoring. Which indicate that the mean surgery time was lower in the group of patients operated with facial monitoring as compared with the unmonitored group. Conclusion So, our meta-analysis shows statistically significant results which favor facial nerve monitoring over no monitoring as regards decreasing the operative time and improving of postoperative facial nerve dysfunction.