Modified arytenoid muscle electrode recording method for neuromonitoring during thyroidectomy

Area of Science:

• Neurosurgery
• Otolaryngology
• Anesthesiology

Background:

• Intraoperative neuromonitoring (IONM) is crucial for recurrent laryngeal nerve (RLN) protection during thyroidectomy.
• Arytenoid muscle electromyography (EMG) recording is a feasible method, but signal parameters require further analysis.
• Modifying needle electrode insertion direction can optimize EMG signal characteristics.

Purpose of the Study:

• To analyze clinical characteristics of EMG signal parameters by altering needle electrode insertion direction.
• To evaluate the safety, feasibility, and reliability of a modified arytenoid muscle EMG recording technique.
• To investigate potential differences in EMG parameters between different sides and patient demographics.

Main Methods:

• Recruited 92 patients undergoing thyroidectomy.
• Inserted paired needle electrodes into bilateral cricothyroid muscle and thyroid cartilage junctions.
• Recorded EMG signals using a four-step method (V1-R1-R2-V2) and confirmed vocal cord function via laryngo-fiberoscopy.

Main Results:

• Successfully recorded 122 RLNs, with no significant changes in EMG amplitude or latency before and after resection.
• Observed normal vocal cord movement postoperatively.
• Found higher amplitude in left nerves compared to right, and shorter latency in right vagus nerves than left.

Conclusions:

• The modified arytenoid muscle EMG recording method is safe, feasible, and reliable for RLN monitoring.
• EMG signal latency differs between right and left vagus nerves.
• EMG signal amplitude may be influenced by the side of nerve recording.