Experience of Intraoperative Recurrent Laryngeal Nerve monitoring in a Single Center-normative Recurrent Laryngeal Nerve Electromyographic Data

Introduction: Injury to the recurrent laryngeal nerve (RLN) remains a significant morbidity during thyroid and parathyroid surgery. The aim of this study is to elucidate normative RLN electromyographic (EMG) parameters. Materials and methods: This is a retrospective cohort study of patients who underwent Intraoperative neuromonitoring during thyroid and parathyroid surgery from February 2014 to March 2015. The inomed C2 NerveMonitor was used. We recorded the stimulation current, amplitude, and latency of the RLN before and after nerve dissection. We also observed the number of patients who had hoarse voice after surgery. Results: A total of 46 patients (14 male, 32 female) averaging 51 years old in age (20−77 years) were analyzed. The most commonly performed surgical procedure was total thyroidectomy (53.2%). The median stimulation current for both the right and left RLN was 0.500 mA. The median amplitude for the left RLN was 1.060 mV and greater than that for the right RLN (0.930 mV) (p = 0.30). The median latency for the right RLN and left RLN was 2.40 ms with no difference between the sides. (p = 0.58). Post dissection, the right RLN amplitude remained identical whereasthe left RLN amplitude decreased. Latencies of both RLNs decreased although the difference was not significant. Nature of pathology and site of surgery did not influence RLN latency and amplitude. No patients had hoarse voice. Conclusion: This study highlights the normative EMG parameters for bilateral RLN nerve stimulation in an Asian population. No significant difference was noted in both preand postdissection RLN EMG parameters.