Shaw scalpel use for recurrent laryngeal nerve dissection: safety parameter findings from continuous intraoperative neuromonitoring in swine models

Abstract

Background: Precise dissection with hemostasis while preserving important structures is critical in thyroid surgeries. In this study, we tested the safety of the Hemostatix Shaw scalpel (HSS) around the recurrent laryngeal nerve (RLN) in porcine models. Methods: Four piglets were used to obtain continuous intraoperative neuromonitoring data. The HSS was applied at various distances from the RLN, with various temperature settings. Monopolar electrosurgical pencil and Harmonic scalpel were also tested for comparison. Results: The use of HSS did not show adverse electromyographic (EMG) events when activated at 3- and 5-mm distances from the RLN. At a 1-mm distance, adverse event was observed at 300 degrees C after 2 seconds of activation. At 210 degrees C, adverse event was observed when the instrument was directly adjacent to the RLN. For comparison, an electrosurgical pencil, set at coagulation mode (25W), showed an irreversible adverse EMG event during 5 seconds of activation at 1-mm distance from the RLN. Harmonic ACE+, activation power at level 5, was also applied in one RLN and reversable adverse EMG event was observed at <0.1-mm (contact) distance after 3 seconds of activation. Conclusions: The safety distance of the HSS was 3 mm for the 300 degrees C setting and >1 mm for the 210 degrees C setting in the swine models in this study. Surgeons must understand the specific characteristics of various energy devices and apply them appropriately for safe operation.