Hye Yoon Lee1, Young Geon Cho2, Ji Young You1, Byoung Ho Choi2, Joon Yub Kim3, Che-Wei Wu4, Feng-Yu Chiang4, Hoon Yub Kim1. 1. Department of Surgery, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea. 2. Advanced Materials Characterization Laboratory at School of Mechanical Engineering, Korea University, Seoul, Korea. 3. Department of Orthopaedic Surgery, Myongji Hospital, Seoul, Korea. 4. Department of Otolaryngology - Head and Neck Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan.
Abstract
BACKGROUND: Recurrent laryngeal nerve (RLN) palsy is the most serious complication after thyroidectomy. However, little is known about the degree of traction injury that causes loss of signal. The purpose of this study was to evaluate traction injuries in the swine RLN using continuous intraoperative neuromonitoring (IONM) and determine the traction power that results in loss of signal. METHODS: Thirteen swine underwent traction injury to the RLNs with continuous IONM, and stress-strain curves were determined for 8 nerves using the universal material testing machine in an ex vivo model. RESULTS: Traction injury at a mean power of 2.83 MPa caused loss of signal. The mean physiologic limit strain and tensile strength of the swine RLNs were found to be 15.0% and 4.9 MPa, respectively. Histological analysis showed no abnormal structural findings. CONCLUSION: Traction injury of swine RLNs causes loss of signal at a power of 2.83 MPa. However, all injured nerves recovered within 7 days with no observed structural damage.
BACKGROUND: Recurrent laryngeal nerve (RLN) palsy is the most serious complication after thyroidectomy. However, little is known about the degree of traction injury that causes loss of signal. The purpose of this study was to evaluate traction injuries in the swine RLN using continuous intraoperative neuromonitoring (IONM) and determine the traction power that results in loss of signal. METHODS: Thirteen swine underwent traction injury to the RLNs with continuous IONM, and stress-strain curves were determined for 8 nerves using the universal material testing machine in an ex vivo model. RESULTS: Traction injury at a mean power of 2.83 MPa caused loss of signal. The mean physiologic limit strain and tensile strength of the swine RLNs were found to be 15.0% and 4.9 MPa, respectively. Histological analysis showed no abnormal structural findings. CONCLUSION: Traction injury of swine RLNs causes loss of signal at a power of 2.83 MPa. However, all injured nerves recovered within 7 days with no observed structural damage.