Standardization of intraoperative neuromonitoring of recurrent laryngeal nerve in thyroid operation.
BACKGROUND
The lack of standardized procedures of intraoperative neuromonitoring (IONM) during thyroid operations may lead to highly variable results, and many of these results can cause misleading information and, conversely, increase the risk of recurrent laryngeal nerve (RLN) injury. Therefore, standardization of IONM procedures is necessary.


METHODS
A total of 289 patients (435 nerves at risk) who underwent thyroidectomy by the same surgeon were enrolled in this study. Each patient was intubated with EMG endotracheal tube by the same anesthesiologist. Standardized IONM procedures were applied in each patient. The procedures include preoperative and postoperative video-recording of vocal cord movement, ensuring the correct position of electrodes after the neck was placed at full extension, vagal stimulation and registration of EMG signals before and after RLN dissection, and photographic documentation of the exposed RLN.


RESULTS
Five patients encountered dysfunction of IONM, which was caused by malposition of electrodes and the problem was detected at once. One patient with non-RLN was detected at the earlier stage of operation. Eighteen nerves experienced loss of EMG signals during thyroid dissection, and the causes of nerve injuries were well elucidated with the application of our standardized IONM procedures.


CONCLUSIONS
The standardized IONM procedures are useful and helpful not only to eliminate false IONM results, but also to elucidate the mechanism of RLN injury. After ascertaining the surgical pitfalls and improving the surgical techniques, the palsy rate was significantly reduced in this study.
Chiang
Feng-Yu
FY
Department of Otolaryngology - Head and Neck Surgery, Faculty of Medicine, College of Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, No. 100, Tzyou First Road, Kaohsiung City, 807, Taiwan.
Lee
Ka-Wo
KW
Chen
Hui-Chun
HC
Chen
Hsiu-Ya
HY
Lu
I-Cheng
IC
Kuo
Wen-Rei
WR
Hsieh
Ming-Chia
MC
Wu
Che-Wei
CW
D016009:Chi-Square Distribution; D004576:Electromyography; D005260:Female; D006801:Humans; D007049:Iatrogenic Disease / Q000517:prevention & control; D007431:Intraoperative Complications / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000592:standards*; D061226:Recurrent Laryngeal Nerve Injuries; D013965:Thyroidectomy / Q000009:adverse effects*; D016896:Treatment Outcome; D014826:Vocal Cord Paralysis / Q000209:etiology / Q000517:prevention & control*