Association Between Facial Nerve Monitoring With Postoperative Facial Paralysis in Parotidectomy

IMPORTANCE Electrophysiologic facial nerve monitoring is becoming an established intraoperative aid to assist the surgeon in facial nerve trunk or branch location and dissection. Limited studies have addressed the postoperative outcomes of parotid surgery with and without monitoring. OBJECTIVE To examine the influence of intraoperative facial nerve monitoring on postoperative facial nerve function and procedure duration in parotid surgery. DESIGN, SETTING, AND PARTICIPANTS An 8-year retrospective review of parotidectomies performed at the Department of Otorhinolaryngology-Head and Neck Surgery, University of Munster. The study analyzed 120 patients undergoing parotidectomy without monitoring from January 1, 1988, to December 31, 1991, and 147 patients undergoing parotidectomy with monitoring from January 1, 2003, to December 31, 2006. The patients were further subdivided in partial parotidectomy (PP) (n = 222) and total parotidectomy (TP) (n = 45) groups. An evaluation of operative time was performed to test the hypothesis of shorter duration of surgery with facial nerve monitoring. Final follow-up was completed on December 31, 2008, and data were analyzed from June 1 to December 31, 2013. MAIN OUTCOMES AND MEASURES Comparison of the incidence of facial nerve dysfunction and operative time between the PP and TP subgroups with and without monitoring. RESULTS A total of 267 patients (127 men [47.6%] and 140 women [52.4%]; mean [SD] age, 51.3 [17.6] years; range, 3-90 years) were included in the analysis. A significant reduction in postoperative facial nerve dysfunction with the use of nerve monitoring could be seen in the PP group (46 of 99 without monitoring [46.5%] vs 18 of 123 with monitoring [14.6%]; P = .001). A similar finding was evident in the TP group when comparing moderate and severe nerve dysfunction (9 of 21 without monitoring [42.9%] vs 2 of 24 with monitoring [8.3%]; P = .01). The mean (SD) operative time in the PP subgroup without nerve monitoring was 115.3 (37.8) minutes; with nerve monitoring, 110.1 (33.6) minutes. The mean (SD) operative time in the TP subgroup without nerve monitoring was 134.5 (50.4) minutes; with nerve monitoring, 158.3 (56.3) minutes. There was no statistical difference between these groups. CONCLUSIONS AND RELEVANCE Facial nerve monitoring in primary parotid surgery for benign and malignant disease does not necessarily reduce the operative time, but the rate of transient postoperative facial nerve dysfunction or the grade of palsy is reduced.