Electromyographic Features of Intermittent Intraoperative Neuromonitorization in The Thyroid Surgery

Abstract

Aim:The aims of this study are, to summarize the trick points of intermittent intraoperative neuromonitoring (I-IONM), outlines of electrophysiologic outcomes of electromyography (EMG), and to determine the electrophysiological properties of left and right recurrent laryngeal nerve (RLN) which anatomical lengths are different from each other.Materials and Methods:34 thyroidectomy cases (27 of total thyroidectomy, 7 of hemithyroidectomy) with use of I-IONM, between June 2016 and June 2017 were retrospectively examined. Pre-dissection (R1, V1) and post-dissection (R2, V2) EMG waveforms of the right and left sides' vagal nerve (VN) and RLN were evaluated.Results:There were 29 females and 5 males patients with mean age of 43.85±13.86 years. 61 nerves at risk were successfully evaluated with I-IONM. Mean R1 and R2 amplitudes of the right RLN were 280±10 μV and 270±9μV; the left RLN were 270±10μV and 260±9μV respectively. Mean V1 and V2 amplitudes of the right VN were 210±7μV and 190±7μV; the left VN were 190±5.4μV and 170±5μV respectively. Mean R1 and R2 latencies of the right RLN were 2.03±0.42mS and 2.0±0.46mS; the left RLN were 1.90 ± 0.30mS and 1.96 ± 0.33mS respectively. Mean V1 and V2 latencies of the right VN were 1.91±0.46mS and 1.82±0.52mS; the left VN were 2.01±0.34mS and 2.07±0.38mS respectively. There was no statistically significant difference between the sides in terms of EMG waveforms of the VN and RLN.Conclusion:The left RLN has a longer anatomical length than the right RLN but we concluded that the length of the nerve does not affect the amplitude and latency.

Keywords

• recurrent laryngeal nerve
• neuromonitoring
• electromyography