Intraoperative Neuromonitoring of Recurrent Laryngeal Nerve During Thyroidectomy with Adhesive Skin Electrodes

Background Alternative methods to overcome limitations of electromyogram (EMG) tube applied for intraoperative neuromonitoring (IONM) of recurrent laryngeal nerve (RLN) during thyroidectomy have been introduced. In this study, we evaluated the feasibility of adhesive skin electrodes for IONM of RLN in patients who underwent thyroidectomy. Methods A total of 39 nerves at risk were prospectively enrolled in this study. Twenty-five patients with papillary thyroid carcinoma, 3 patients with follicular neoplasm, and 2 patients with Graves' disease underwent thyroidectomy. All patients were intubated with EMG tube, and two disposable pre-gelled surface electrodes were attached to skin at both upper margins of thyroid cartilage. We followed the standard procedure of IONM, and the latency (msec) and amplitude (mu V) of each signal were recorded prospectively. Results Intraoperative neuromonitoring using skin adhesive electrodes was successful in all nerves at risk. Amplitudes of the signals in IONM were significantly lower compared to those from EMG tube at each step of IONM, while no significant difference was identified in latency between two methods. Four nerves at risk (10.3%) showed loss of signal (<100 mu V) during the steps of IONM from EMG tube, while all nerves at risk from adhesive skin electrodes showed acceptable biphasic EMG signal. Conclusion We verified the usefulness of adhesive skin electrodes for IONM of RLN during thyroidectomy. Although lower amplitude remains the major limitation of this technique, adhesive skin electrodes may be considered an alternative method for IONM during thyroidectomy.