Wu, Che-Wei 1, Chiang, Feng-Yu1, Randolph, Gregory W.2, Dionigi, Gianlorenzo3, Kim, Hoon Yub4, Lin, Yi-Chu1, Chang, Pi-Ying5, Lu, I-Cheng5.
1 Department of Otolaryngology-Head and Neck Surgery, Kaohsiung Medical University Hospital and Kaohsiung Municipal Siaogang Hospital; Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
2 Division of Thyroid and Parathyroid Endocrine Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary; Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts, USA
3 1st Division of General Surgery, Research Center for Endocrine Surgery, Department of Medicine and Surgery, ASST Sette Laghi Ospedale di Circolo e Fondazione Macchi- Polo Universitario, University of Insubria (Varese-Como),
4 Department of Surgery, Korea University College of Medicine, Seoul, Korea.
5 Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
Background: Endotracheal tube-based (ETT) surface recording electrodes systems are now commonly applied during intraoperative neuromonitoring (IONM) in thyroid surgery. An ETT that is mispositioned can cause false IONM result, and the need to verify or readjust the ETT position is time-consuming intraoperatively. This experimental study aimed to determine the feasibility of the trans-cutaneous approach for recording of evoked laryngeal electromyography (EMG) during IONM.
Method: Eight piglets (16 nerve sides) were enrolled, and electrically evoked EMG was recorded from both the ETT-based electrodes and the adhesive pre-gelled electrodes put on the neck skin at the level of upper border of left and right lamina of thyroid cartilage. The evoked EMG waveforms were measured and analyzed.
Result: Both ETT and neck skin recording electrodes recorded typical evoked laryngeal EMG waveforms from the bilateral vagus nerve and recurrent laryngeal nerves (RLNs) stimulation with 1 mA current. The mean recorded amplitude was 937 +/- 143 µV from ETT, and 237 +/- 67 µV from neck skin electrodes during the RLN stimulation.
Conclusion: Trans-cutaneous recording of evoked laryngeal EMG is feasible during IONM. Future animal and clinical studies are needed to investigate its stability during surgical manipulation, and the accuracy in reflecting a neurophysiologic event.