Is it possible to predict postoperative facial nerve function by monitorization during parotidectomy

Abstract

This study aims to assess the value of facial nerve monitorization and minimum facial nerve stimulation thresholds during superficial parotidectomy in the prediction of postoperative facial nerve function. Twenty superficial parotidectomy patients (9 males, 11 females; mean age 52 years; range 23 to 80 years), who treated in our clinic between January 2013 and May 2013 were recruited in this study. Intraoperative facial nerve monitorization was applied and minimum facial nerve stimulation thresholds were recorded in the main trunk at the end of the operation. Postoperative facial nerve functions were evaluated by House Brackmann (HB) grading system. In early postoperative evaluation, minimum stimulation thresholds of 12 patients with facial nerve function HB grade 1 (normal) and of eight patients with HB grade 2 facial paresis in marginal mandibular branch were 0.20±0.14 mA and 0.22±0.05 mA respectively (p>0.05). At the end of the first day, minimum stimulation thresholds in 17 HB grade 1 patients and three HB grade 2 patients were 0.20±0.12 mA and 0.25±0.07 mA, respectively (p>0.05). No significant difference was detected in terms of stimulation thresholds between patients who developed or did not develop postoperative facial paresis. All patients were HB grade 1 at the end of third month. No correlation was found between tumor size and postoperative facial nerve function (p>0.05). Minimum facial nerve stimulation thresholds during superficial parotidectomy were not effective in the prediction of postoperative mild facial nerve paresis.