EXPERIENCE WITH 2 TYPES OF ELECTROMYOGRAPHY MONITORING ELECTRODES DURING THYROID-SURGERY

Purpose: To prevent damage to the recurrent laryngeal nerve during thy roid or parathyroid surgery, spontaneous and evoked electromyography ( EMG) can be used to locate the recurrent laryngeal nerve or determine when the nerve is being disturbed. Two commercial electrodes have been introduced to receive laryngeal EMG. This study compares the clinical performance of the two electrodes. Patients and Methods: The Xomed-Tr eace endotracheal tube electrode (Xomed-Treace, Jacksonville, FL) and the RLN postericoid laryngeal electrode (RLN Systems, Jefferson City, MO) were placed concomitantly in 11 patients during 14 surgical proced ures. Results: The RLN electrode provided feedback as to placement by providing a heart-beat artifact. The RLN electrode was found to be bot h more sensitive and more electrically noisy. On stimulation, the Xome d tube electrode produced generally higher EMG amplitudes, perhaps bec ause of the different muscles they monitor. In one case, the Xomed tub e failed to provide EMG responses. Only at low electrical stimulation intensities could left and right vocalis muscles be identified with th e Xomed tube. A laryngologist was needed to place the RLN electrode, w hereas the attending anesthesiologist was able to place the Xomed tube . Conclusion: Both electrodes provided useful EMG information and help ed confirm the location of the recurrent laryngeal nerve. Who will pla ce the electrode, tumors extrinsic or intrinsic to the larynx, cost, a nd size requirements should be considered when choosing an electrode. Copyright (C) 1997 by W.B. Saunders Company.