Safe distance from facial nerve for bipolar coagulation in parotid surgery-Animal study.

OBJECTIVE: Currently no data exist on what distance from facial nerve (FN) it is safe to perform bipolar cautery (BC) in parotid surgery, although frequently performed. METHODS: The degree of damage was measured using continuous intraoperative neuromonitoring (cIONM, NIM 3, Medtronic) in 16 Wistar rats. Amplitude drop of at least 50% (A(50)) or a loss of signal (LOS) in the cIONM was defined as harmful; BC was performed in power range 20-60 W. RESULTS: BC </=30 W did not cause LOS (0/14 nerves). When applying 35 W, A(50) occurred at 4 mm from FN and LOS was noted in 1 of 5 nerves. BC at a power of 40 to 60 W demonstrated LOS in all nerves (12/12) at a 5 mm distance. CONCLUSION: BC up to 30 W can be safely applied up to 3 mm distance from FN. 40 to 60 W should be avoided and used only at a distance of over 6 mm from FN. LEVEL OF EVIDENCE: NA/animal study. Laryngoscope, 135:1120-1126, 2025.