Feasibility of facial nerve monitoring using adhesive surface electrodes during parotidectomy: a comparative study with needle electrodes.

Abstract

Electrophysiological monitoring of the facial nerve during parotidectomy has been reported as an adjunctive method to prevent facial nerve injury. Classically, a needle electrode is used to obtain electromyographic (EMG) signals from facial muscles during facial nerve monitoring (FNM) of parotid surgery, likewise adhesive surface electrodes. This study aimed to investigate the feasibility of performing FNM with surface electrodes during parotid surgery and to compare EMG values with needle electrodes. Thirty patients who underwent parotidectomy under FNM using adhesive surface and needle electrodes were included. Two pairs of adhesive surface electrodes and needle electrodes were used for FNM during parotid surgery. Mean amplitudes were collected after electrical facial nerve stimulation at 1mA after specimen removal. The mean amplitude of the adhesive surface electrodes was 226.50 ± 118.44μV (orbicularis oculi muscle) and 469.6 ± 306.06μV (orbicularis oris muscle), respectively. The mean amplitude of the needle electrodes was 449.85 ± 248.10μV (orbicularis oculi muscle) and 654.66 ± 395.71μV (orbicularis oris muscle), respectively. The mean amplitude of the orbicularis oris muscle was significantly greater than that of the orbicularis oculi. The amplitude values measured in the orbicularis oculi muscle showed significant differences between the needle and skin electrodes. Facial nerve monitoring (FNM) using adhesive surface electrodes is feasible in parotid surgery. Although the mean amplitude value of the surface electrode was relatively lower than that of the needle electrode, the surface electrode is considered a feasible and safe EMG recording device for FNM in parotid surgery.