The potential applicability of facial nerve monitoring as a navigation tool in parotid gland surgery

Abstract Objectives: The aim of this study was to assess the relationship between the stimulation amplitude and the distance to the facial nerve. Methods: This study was designed as a prospective clinical study. A total of 20 patients (12 males, 8 females) were included. Partial superficial parotidectomy was performed in all patients with intraoperative facial monitoring. Measurements were made on the main trunk and major branches. Stimulation was started at 1 mA and incrementally increased to 2 and 3mA’s. The shortest distance creating a robust response (>100mV) was recorded. Results: At 1 mA, 2 mA and 3 mA stimulation intensity, the average distance between the tip of the stimulation probe and the main trunk was 2.20±0.76 mm (range 1-3 mm), 3.80±0.95 mm (range 2-5 mm), 4.80±1.05 mm (range 3-7 mm) respectively. The stimulus intensity was inversely proportional in respect to the distance between the nerve and the tip of the stimulus probe (P