Gianlorenzo Dionigi1, Feng-Yu Chiang2,3, Hoon Yub Kim4, Gregory W Randolph5, Alberto Mangano1, Pi-Ying Chang6, I-Cheng Lu6, Yi-Chu Lin2,3, Hui-Chun Chen7, Che-Wei Wu2,3. 1. 1st Division of Surgery, Research Center for Endocrine Surgery, Department of Surgical Sciences and Human Morphology, University of Insubria (Como-Varese), Varese, Italy. 2. Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. 3. Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 4. Department of Surgery, KUMC Thyroid Center, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea. 5. Division of Thyroid and Parathyroid Endocrine Surgery, Department of Laryngology and Otology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, U.S.A. 6. Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. 7. Department of Nursing, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
Abstract
OBJECTIVES/HYPOTHESIS: This study investigated recurrent laryngeal nerve (RLN) real-time electromyography (EMG) data to define optimal safety parameters of the LigaSure Small Jaw (LSJ) instrument during thyroidectomy. STUDY DESIGN: Prospective animal model. METHODS: Dynamic EMG tracings were recorded from 32 RLNs (16 piglets) during various applications of LSJ around using continuous electrophysiologic monitoring. At varying distances from the RLN, the LSJ was activated (activation study). The LSJ was also applied to the RLN at timed intervals after activation and after a cooling maneuver through placement on the sternocleidomastoid muscle (cooling study). RESULTS: In the activation study, there was no adverse EMG event at 2 to 5 mm distance (16 RLNs, 96 tests). In the cooling study, there was no adverse EMG event after 2-second cooling time (16 RLNs, 96 tests) or after the LSJ cooling maneuver on the surrounding muscle before reaching the RLNs (8 RLNs, 24 tests). CONCLUSION: Based on EMG functional assessment, the safe distance for LSJ activation was 2 mm. Further LSJ-RLN contact was safe if the LSJ was cooled for more than 2 seconds or cooled by touch muscle maneuver. The LSJ should be used with these distance and time parameters in mind to avoid RLN injury. LEVEL OF EVIDENCE: N/A. Laryngoscope, 127:1724-1729, 2017.
OBJECTIVES/HYPOTHESIS: This study investigated recurrent laryngeal nerve (RLN) real-time electromyography (EMG) data to define optimal safety parameters of the LigaSure Small Jaw (LSJ) instrument during thyroidectomy. STUDY DESIGN: Prospective animal model. METHODS: Dynamic EMG tracings were recorded from 32 RLNs (16 piglets) during various applications of LSJ around using continuous electrophysiologic monitoring. At varying distances from the RLN, the LSJ was activated (activation study). The LSJ was also applied to the RLN at timed intervals after activation and after a cooling maneuver through placement on the sternocleidomastoid muscle (cooling study). RESULTS: In the activation study, there was no adverse EMG event at 2 to 5 mm distance (16 RLNs, 96 tests). In the cooling study, there was no adverse EMG event after 2-second cooling time (16 RLNs, 96 tests) or after the LSJ cooling maneuver on the surrounding muscle before reaching the RLNs (8 RLNs, 24 tests). CONCLUSION: Based on EMG functional assessment, the safe distance for LSJ activation was 2 mm. Further LSJ-RLN contact was safe if the LSJ was cooled for more than 2 seconds or cooled by touch muscle maneuver. The LSJ should be used with these distance and time parameters in mind to avoid RLN injury. LEVEL OF EVIDENCE: N/A. Laryngoscope, 127:1724-1729, 2017.