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Objective: Endotracheal tube (ETT) surface electrodes are used to monitor the vagus nerve (VN), recurrent laryngeal nerve (RLN), and external branch of the superior laryngeal nerve (EBSLN) during thyroid and parathyroid surgery. Alternative nerve monitoring methods are desirable when intubation under general anesthesia is not desirable or possible. In this pilot study, we compared the performance of standard ETT electrodes to four different noninvasive cutaneous recording electrode types (two adhesive electrodes and two needle electrodes) in three different orientations., Methods: The VN was stimulated directly during thyroid and parathyroid surgery using a Prass stimulator probe. Electromyographic (EMG) responses for each patient were recorded using an ETT plus one of the following four cutaneous electrode types: large-foot adhesive, small-foot adhesive, long-needle and short-needle. Each of the four electrode types was placed in three orientations: (1) bilateral, (2) ipsilateral mediolateral, and (3) ipsilateral craniocaudal., Results: Four surgical cases were utilized for data collection with the repetitive measures obtained in each subject. Bilateral electrode orientation was superior to ipsilateral craniocaudal and ipsilateral mediolateral orientations. Regardless of electrodes type, all amplitudes in the bilateral orientation were >100 μV. When placed bilaterally, the small-foot adhesive and the long-needle electrodes obtained the highest EMG amplitudes as a percentage of ETT amplitudes., Conclusion: Cutaneous electrodes could potentially be used to monitor the VN during thyroid and parathyroid procedures. Different electrode types vary in their ability to record amplitudes and latencies. Bilateral orientation improves EMG responses in all electrode types. Additional validation of cutaneous electrodes as an alternative noninvasive method to monitor the VN is needed., (© 2024 Wiley Periodicals LLC.)

Objectives/hypothesis: During intraoperative neuromonitoring in thyroid surgery, two different kinds of stimulator probes, monopolar and bipolar, are commonly used to stimulate the laryngeal nerves. We explore the unique characteristics of both of these probes as they relate to intraoperative laryngeal nerve mapping., Methods: Twenty-one patients undergoing neuromonitored thyroidectomy by a single surgeon were enrolled. Electromyography (EMG) amplitude and latency measurements were prospectively recorded concurrently from 1 mA stimulation of vagus nerve (VN) and inferior/superior recurrent laryngeal nerve before (with and without fascia) and after thyroid resection using bipolar and monopolar stimulator probes., Results: Significantly higher amplitudes were obtained with monopolar stimulator probes as compared to bipolar probes, in several stimulation scenarios such as at right VN pre-resection (carotid sheath intact), right VN pre-resection (carotid sheath dissected), right VN post-resection and left VN (carotid sheath dissected). No significant differences were found between amplitudes and latency values in all other stimulation scenarios., Conclusions: According to this study, both probes are reliable and safe for neural mapping. The kind of probe used during neural monitoring is based on surgical situations and surgeon preference., Level of Evidence: 3 (According to Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence) Laryngoscope, 131:E2718-E2726, 2021., (© 2021 The American Laryngological, Rhinological and Otological Society, Inc.)