Comparison of EMG amplitudes recorded by ipsilateral and contralateral electrodes placement during using trans-thyroid cartilage recording method in thyroid surgery

Feng-Yu Chiang; Yu-Chen Shih; Ching-Feng Lien; Chih-Chun Wang; Chien-Chung Wang; Tzer-Zen Hwang; Yaw-Chang Huang; Che-Wei Wu; Tai-Hung Yeh; Tzu-Yen Huang

doi:10.3389/fendo.2023.1305629

Comparison of EMG amplitudes recorded by ipsilateral and contralateral electrodes placement during using trans-thyroid cartilage recording method in thyroid surgery

Front Endocrinol (Lausanne). 2024 Jan 16:14:1305629. doi: 10.3389/fendo.2023.1305629. eCollection 2023.

Authors

Feng-Yu Chiang^{1

2}, Yu-Chen Shih³, Ching-Feng Lien^{1

2}, Chih-Chun Wang^{1

2}, Chien-Chung Wang¹, Tzer-Zen Hwang^{1

2}, Yaw-Chang Huang¹, Che-Wei Wu⁴, Tai-Hung Yeh¹, Tzu-Yen Huang^{4

5}

Affiliations

¹ Department of Otolaryngology-Head and Neck Surgery, E-Da Hospital, Kaohsiung, Taiwan.
² School of Medicine, College of Medicine, I-Shou University, Kaohsiung, Taiwan.
³ Department of Otolaryngology, E-Da Cancer Hospital, Kaohsiung, Taiwan.
⁴ Department of Otorhinolaryngology-Head and Neck Surgery, International Thyroid Surgery Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁵ Department of Otorhinolaryngology, School of Post-Baccalaureate Medicine and School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.

Abstract

Objectives: The feasibility and reliability of trans-thyroid cartilage EMG recording method (TCERM) during intraoperative monitoring (IONM) of the recurrent laryngeal nerve (RLN) in thyroid surgery have been established. This study compared two different recording electrode placements on the ipsi-lateral and contra-lateral lamina of the thyroid cartilage (TC).

Methods: Fifty consecutive patients undergoing total thyroidectomy with 100 RLNs at risk were enrolled. Two paired subdermal needle electrodes were inserted into the subperichondrium of the bilateral TC lamina to record electromyography (EMG) signals. The channel leads from the TC electrodes were connected to the patient interface with two different modes. In A-mode, the electrode leads were placed ipsi-laterally, and channel 1 monitored the left RLN and channel 2 monitored the right RLN respectively. In B-mode, the electrode leads were placed contra-laterally, and channels 1 and 2 simultaneously monitored the same side of the RLN. The amplitudes of four EMG signals (V₁-R₁-R₂-V₂) recorded by A-mode and B-mode were compared.

Results: All EMG amplitudes of V₁-R₁-R₂-V₂ signals recorded with B-mode were all above 500μV and significantly higher than those with A-mode (p<0.001). No false loss of signal, electrode dislodgement, or needle-related complications were noted during IONM. Postoperatively, all patients had symmetrical vocal cord movement. Lower EMG amplitudes were observed in older and male patients. Histopathology and laterality showed no significant differences in EMG amplitude.

Conclusion: During using TCERM in thyroid surgery, the recording electrodes should be placed contra-laterally on the TC lamina. This approach ensures high and stable EMG signals, which are important for high-quality IONM of the RLN.

Keywords: electromyography (EMG); intraoperative neuromonitoring (IONM); recording method; recurrent laryngeal nerve (RLN); thyroid surgery.

Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Aged
Electrodes
Humans
Male
Reproducibility of Results
Thyroid Cartilage* / innervation
Thyroid Gland* / surgery
Thyroidectomy / adverse effects
Thyroidectomy / methods

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was supported by grants from Kaohsiung Medical University Hospital, Kaohsiung Medical University (KMUH111-1R48, KMUH111-1R49), and National Science and Technology Council (NSTC112-2314-B-037-033, NSTC 112-2314-B-037-034), Taiwan.