Modified transcricothyroid electrode recording method for monitoring recurrent laryngeal nerve function during thyroidectomy / 中华内分泌外科杂志

ABSTRACT

Objective:To study the safety, validity and practicability of the modified trans-cricothyroid needle electrode method for neurmonitoring during thyroidectomy.Methods:115 patients from the Department of Thyroid Surgery in Peking University Shenzhen Hospital scheduled for thyroid surgery were recruited into the group. Two paired needle electrodes were obliquely inserted into the cricothyroid membrane from the angle between the rectus cricothyroid muscle and the inferior margin of thyroid cartilage. The function of recurrent laryngeal nerve (RLN) was localized, exposed and evaluated by standard four-step method (V1-R1-R2-V2) . The vocal cord movement was evaluated by electronic laryngoscope before and after operation, and t-test was used to compare the difference of EMG signal amplitude before and after operation.Results:A total of 130 RLN from 115 patients were recorded effective electromyographic (EMG) signals, including 12 cases of giant goiter with tracheal compression stenosis; 13 cases had repeated adjustments of the position of tracheal intubation electrode during operation, but EMG signals were not satisfactory; 15 cases were with of accidental findings during operation and requiring neurmonitoring, but tracheal intubation electrodes were not used in advance. 75 cases were volunteers. The signals of 3 RLN were lost during operation. On the second day after operation, electronic laryngoscope showed that 2 cases had normal vocal cord movement and 1 case had vocal cord paralysis and no recovery for 6 months follow-up. The EMG signals of other 127 nerves were V1/R1=1857±1718μV/2347±2323μV, V2/R2=1924±1705μV/2450±2345μV. There was no significant difference in EMG signals between pre-operation and post-operation ( t=0.31/0.35, P=0.755/0.725) . The electronic laryngoscope showed normal vocal cord movement before and after operation. During the operation, 2 patients had a little bleeding at the needle electrode insertion point, which stopped after 5 minutes of compression. No electro-acupuncture breakage, infection or local hematoma occurred. Conclusions:The modified trans-cricothyroid needle electrode method had been proved to be safe and feasible for evaluating the function of recurrent laryngeal nerve in thyroid surgery. Besides of unaffected by tracheal conditions, it has good stability, simple implantation and low cost. In thyroid surgery, it can be used as a useful supplement to endotracheal intubation electrode.