Marcus Benjamin, Edwards Bruce, Yoo Sirius, Byrne Anne, Gupta Anurag, Kandrevas Janet, Bradford Carol, Chepeha Douglas B, Teknos Theodoros N
Department of Otolaryngology-Head and Neck Surgery, University of Michigan Health System, Ann Arbor, Michigan 48109-0312, USA.
Laryngoscope. 2003 Feb;113(2):356-61. doi: 10.1097/00005537-200302000-00028.
OBJECTIVES/HYPOTHESIS: Intraoperative monitoring of the recurrent laryngeal nerve (RLN) is finding increasing acceptance during thyroidectomy. Recently, a laryngeal surface electrode was introduced to enable another form of noninvasive monitoring of the RLN. The present report examines the University of Michigan experience with RLN monitoring using the postcricoid surface electrode.
All patients undergoing partial or total thyroidectomy or parathyroidectomy from January 1999 to July 2001 were considered candidates for the study. Audiologists trained in intraoperative electrophysiological techniques performed all of the monitoring.
Data collected on each patient included 1) stimulation threshold for a laryngeal compound muscle action potential on initial RLN identification, 2) stimulation threshold of the laryngeal compound muscle action potential on completion of the procedure, and 3) flexible fiberoptic evaluation of the larynx at the initial postoperative visit and at the 3-month follow-up visit. The average duration of follow-up was 9.8 months with a range of 3 to 60 months.
The average minimum current required for stimulation on first identification of all nerves was 0.57 mA (+/-0.48 mA). After completion of the procedure a mean threshold level of 0.42 mA (+/-0.55 mA) was obtained during direct RLN stimulation. Post-dissection stimulation of the RLN on the side of tumor dissection was 0.92 mA (+/-0.65 mA) compared with a stimulation threshold of 0.76 mA (+/-0.57 mA) for the nontumor side.
Electromyographic monitoring of the RLN using a postcricoid surface electrode provides a safe, simple, and effective method for intraoperative monitoring during thyroid or parathyroid surgery. Further, evoked electromyography confirms RLN integrity at the conclusion of surgery.
目的/假设：术中对喉返神经（RLN）的监测在甲状腺切除术中越来越被广泛接受。最近，一种喉部表面电极被引入，以实现对喉返神经的另一种非侵入性监测形式。本报告探讨了密歇根大学使用环状软骨后表面电极进行喉返神经监测的经验。
1999年1月至2001年7月期间接受部分或全部甲状腺切除术或甲状旁腺切除术的所有患者均被视为该研究的候选对象。接受术中电生理技术培训的听力学家进行了所有监测。
收集的每位患者的数据包括：1）初次识别喉返神经时喉复合肌动作电位的刺激阈值；2）手术完成时喉复合肌动作电位的刺激阈值；3）术后初次就诊和3个月随访时对喉部进行的纤维喉镜评估。平均随访时间为9.8个月，范围为3至60个月。
初次识别所有神经时刺激所需的平均最小电流为0.57 mA（±0.48 mA）。手术完成后，直接刺激喉返神经时的平均阈值水平为0.42 mA（±0.55 mA）。肿瘤切除侧喉返神经解剖后的刺激电流为0.92 mA（±0.65 mA），而非肿瘤侧的刺激阈值为0.76 mA（±0.57 mA）。
使用环状软骨后表面电极对喉返神经进行肌电图监测为甲状腺或甲状旁腺手术中的术中监测提供了一种安全、简单且有效的方法。此外，诱发电位肌电图在手术结束时证实了喉返神经的完整性。
