Whitney Liddy1, Che-Wei Wu2, Gianlorenzo Dionigi3, Gianluca Donatini4, Yasemin Giles Senyurek5, Dipti Kamani6, Ayaka Iwata6,7, Bo Wang6,8, Okenwa Okose6, Anthony Cheung6, Yoshiyuki Saito6,9, Claudio Casella10, Nurcihan Aygun11, Mehmet Uludag11, Katrin Brauckhoff12,13, Bruno Carnaille14, Fatih Tunca5, Marcin Barczyński15, Hoon Yub Kim16,17, Emerson Favero18, Nadia Innaro19, Kyriakos Vamvakidis20, Jonathan Serpell21, Anatoly F Romanchishen22, Hiroshi Takami23, Feng-Yu Chiang24, Rick Schneider25, Henning Dralle26, Jennifer J Shin27,28, Amr H Abdelhamid Ahmed6, Gregory W Randolph6,29. 1. Department of Otolaryngology-Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA. 2. Department of Otolaryngology-Head and Neck Surgery, Faculty of Medicine, Kaohsiung Medical University Hospital, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 3. Division for Endocrine and Minimally Invasive Surgery, Department of Human Pathology in Adulthood and Childhood "Gaetano Barresi," University Hospital G. Martino, University of Messina, Messina, Italy. 4. Department of Visceral and Endocrine Surgery, CHU Poitiers-University of Poitiers, Poitiers, France. 5. Department of General Surgery, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey. 6. Division of Thyroid and Parathyroid Endocrine Surgery, Department of Otolaryngology-Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA. 7. Department of Otolaryngology-Head and Neck Surgery, Kaiser Permanente Santa Clara Medical Center, Santa Clara, California, USA. 8. Department of Thyroid and Parathyroid Surgery, Fujian Medical University Union Hospital, Fujian, China. 9. Department of Surgery, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Tokyo, Japan. 10. Department of Molecular and Translational Medicine, School of Medicine, University of Brescia Surgical Clinic, Spedali Civili Brescia, Brescia, Italy. 11. Department of General Surgery, University of Health Sciences Turkey, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey. 12. Department of Breast and Endocrine Surgery, Haukeland University Hospital, Bergen, Norway. 13. Department of Clinical Science, University of Bergen, Bergen, Norway. 14. Department of General and Endocrine Surgery, Lille University Hospital, Lille University, Lille, France. 15. Department of Endocrine Surgery, Third Chair of General Surgery, Jagiellonian University, Medical College, Kraków, Poland. 16. Department of Surgery, Korea University Thyroid Center, Korea University College of Medicine, Seongbuk-gu, Seoul, Korea. 17. Division of Endocrine and Oncologic Surgery, Department of Surgery, Tulane University School of Medicine, New Orleans, Louisiana, USA. 18. Department of Head and Neck Surgery, School of Medicine, University of Mogi das Cruzes, São Paulo, Brazil. 19. Unit of Endocrine Surgery, AOU Mater Domini, Catanzaro, Italy. 20. Department of Endocrine Surgery, "Henry Dunant" Hospital Center, Athens, Greece. 21. Med, Breast, Endocrine and General Surgery Unit, Alfred Health, Monash University, Melbourne, Victoria, Australia. 22. St. Petersburg State University, St. Petersburg, Russia. 23. Department of Surgery, Ito Hospital, Shibuya-ku, Tokyo, Japan. 24. Department of Otolaryngology, E-Da Hospital, School of Medicine, College of Medicine, I-Shou University, Kaohsiung, Taiwan. 25. Department of Visceral, Vascular and Endocrine Surgery, University Hospital Halle, Martin-Luther University, Halle (Saale), Germany. 26. Division of Endocrine Surgery, Department of General, Visceral and Transplantation Surgery, University of Duisburg Essen, Essen, Germany. 27. Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA. 28. Center for Surgery and Public Health, Brigham and Women's Hospital, Boston, Massachusetts, USA. 29. Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Abstract
Background: The recurrent laryngeal nerve (RLN) can be injured during thyroid surgery, which can negatively affect a patient's quality of life. The impact of intraoperative anatomic variations of the RLN on nerve injury remains unclear. Objectives of this study were to (1) better understand the detailed surgical anatomic variability of the RLN with a worldwide perspective; (2) establish potential correlates between intraoperative RLN anatomy and electrophysiologic responses; and (3) use the information to minimize complications and assure accurate and safe intraoperative neuromonitoring (IONM). Methods: A large international registry database study with prospectively collected data was conducted through the International Neural Monitoring Study Group (INMSG) evaluating 1000 RLNs at risk during thyroid surgery using a specially designed online data repository. Monitored thyroid surgeries following standardized IONM guidelines were included. Cases with bulky lymphadenopathy, IONM failure, and failed RLN visualization were excluded. Systematic evaluation of the surgical anatomy of the RLN was performed using the International RLN Anatomic Classification System. In cases of loss of signal (LOS), the mechanism of neural injury was identified, and functional evaluation of the vocal cord was performed. Results: A total of 1000 nerves at risk (NARs) were evaluated from 574 patients undergoing thyroid surgery at 17 centers from 12 countries and 5 continents. A higher than expected percentage of nerves followed an abnormal intraoperative trajectory (23%). LOS was identified in 3.5% of NARs, with 34% of LOS nerves following an abnormal intraoperative trajectory. LOS was more likely in cases of abnormal nerve trajectory, fixed splayed or entrapped nerves (including at the ligament of Berry), extensive neural dissection, cases of cancer invasion, or when lateral lymph node dissection was needed. Traction injury was found to be the most common form of RLN injury and to be less recoverable than previous reports. Conclusions: Multicenter international studies enrolling diverse patient populations can help reshape our understanding of surgical anatomy during thyroid surgery. There can be significant variability in the anatomic and intraoperative characteristics of the RLN, which can impact the risk of neural injury.
Background: The recurrent laryngeal nerve (RLN) can be injured during thyroid surgery, which can negatively affect a patient's quality of life. The impact of intraoperative anatomic variations of the RLN on nerve injury remains unclear. Objectives of this study were to (1) better understand the detailed surgical anatomic variability of the RLN with a worldwide perspective; (2) establish potential correlates between intraoperative RLN anatomy and electrophysiologic responses; and (3) use the information to minimize complications and assure accurate and safe intraoperative neuromonitoring (IONM). Methods: A large international registry database study with prospectively collected data was conducted through the International Neural Monitoring Study Group (INMSG) evaluating 1000 RLNs at risk during thyroid surgery using a specially designed online data repository. Monitored thyroid surgeries following standardized IONM guidelines were included. Cases with bulky lymphadenopathy, IONM failure, and failed RLN visualization were excluded. Systematic evaluation of the surgical anatomy of the RLN was performed using the International RLN Anatomic Classification System. In cases of loss of signal (LOS), the mechanism of neural injury was identified, and functional evaluation of the vocal cord was performed. Results: A total of 1000 nerves at risk (NARs) were evaluated from 574 patients undergoing thyroid surgery at 17 centers from 12 countries and 5 continents. A higher than expected percentage of nerves followed an abnormal intraoperative trajectory (23%). LOS was identified in 3.5% of NARs, with 34% of LOS nerves following an abnormal intraoperative trajectory. LOS was more likely in cases of abnormal nerve trajectory, fixed splayed or entrapped nerves (including at the ligament of Berry), extensive neural dissection, cases of cancer invasion, or when lateral lymph node dissection was needed. Traction injury was found to be the most common form of RLN injury and to be less recoverable than previous reports. Conclusions: Multicenter international studies enrolling diverse patient populations can help reshape our understanding of surgical anatomy during thyroid surgery. There can be significant variability in the anatomic and intraoperative characteristics of the RLN, which can impact the risk of neural injury.
Entities:
Keywords:
intraoperative neural monitoring; loss of signal; neural injury; recurrent laryngeal nerve; surgical anatomy; thyroid surgery