甲状腺手术中喉返神经监测的电流刺激强度及其潜伏期的临床研究

Clinical study of monitoring the appropriate current stimulation intensity and latency of recurrent laryngeal nerve during thyroid surgery

目的探讨喉返神经术中神经监测(intraoperative nerve monitoring,IONM)的适宜刺激电流强度以及相应潜伏期,评估甲状腺手术中对喉返神经的保护及预测神经损伤程度的临床价值。方法收集在甲状腺手术使用IONM患者35例的临床资料,其中有损伤风险的喉返神经42条。用0.1~3.0mA的电流强度直接刺激喉返神经,记录其肌电信号振幅,寻求术中IONM各阶段最适宜的电流强度;用1mA电流分别刺激喉返神经入喉处、距入喉1cm处、距入喉2cm处,记录相应的潜伏期,并以此计算喉返神经传导速度。结果刺激电流≥0.5mA时,神经监测仪上均显示喉返神经振幅,且振幅稳定,为振幅最大值。刺激电流<0.5~0.2mA时,随刺激电流减小振幅减低至无法读出。用1mA电流刺激42条喉返神经入喉处、距入喉1cm处、距入喉2cm处,分别读出潜伏期t_0、t_1、t_2。传导距离为1cm时,其传导所需时间分别为(t_1-t_0)、(t_2-t_1)、(t_2-t_0)/2。据此分别计算出3组的传导速度。3组间潜伏期和传导速度差异无统计学意义(P>0.05)。结论最适宜电流刺激强度为0.5mA,即为阈值;确定喉返神经的潜伏期,并以此计算出喉返神经传导速度为4cm/ms,进而当喉返神经损伤时,根据潜伏期可计算出损伤点至效应器的距离。

Objective To explore the normality of the recurrent laryngeal nerve in the thyroid surgery to monitor the appropriate intensity of the stimulus and the latency,in order to evaluate the clinical value of intraoperative laryngeal protection and predict the degree of nerve injury.Methods Prospective collection of clinical data from 35 patients who underwent thyroid surgery and the use of intraoperative nerve monitoring,with 45 lesions with risk of injury.According to the normalized neural monitoring process,the recurrent laryngeal nerve was directly stimulated with the current intensity of 0.1-3mA,and the amplitude of the electromyographic signal was recorded. The optimal current intensity was measured at each stage of the intraoperative nerve monitoring.With 1 mA current to stimulate the recurrent laryngeal nerve into the throat,from the larynx 1cm,2cm away from the larynx,record the corresponding latency,and to calculate the conduction velocity of recurrent laryngeal nerve.ResultsStimulation current greater than or equal to 0.5 mA,the stimulation of the recurrent laryngeal nerve in the nerve monitor are displayed on the amplitude and the maximum amplitude,and these amplitudes are stabie.When the stimulus current is less than 0.5mA,the amplitude is lowered to the point where it cannot be read out as the stimulus current decreases.With 1mA current to stimulate the 42 recurrent laryngeal nerves into the throat,from the larynx 1cm,2cm away from the throat,respectively,we get the latency t_0,t_1,t_2.When the conduction distance is 1cm,the conduction time is（t_1-t_0）,（t_2-t_1）,（t_2-t_0）/2respectively.There was no significant difference in the conduction time and the conduction velocity between the three groups.Conclusion The optimal current stimulation intensity is 0.5 mA,also it is the threshold.We identified the latency of the recurrent laryngeal nerve,and calculated the conduction velocity of recurrent laryngeal nerve is 4cm/ms.We can calculate the distance from the damage point to the effector according to the latency when the recurrent laryngeal nerve is damaged.