摘要：
Objective To investigate the efficacy of neurological injury in patients with Hirayama disease using threshold tracking technique.Methods This study included 17 patients with Hirayama disease who visited the Department of Orthopaedics of Huashan Hospital from June 2017 to October 2017(patient group,16 males and 1 female,the average age was 18.06±0.50 years,ranging from 16 to 22 years,the average course of disease was 27.2±18.81 months,ranging from 1 to 60 months.Mean-while,a total of 20 healthy volunteers(control group,19 males and 1 female,the average age is 20.05±1.30 years,ranging from 17 to 23 years)were also enrolled in this study.In patient group,the median motor nerve conduction examination,needle EMG examination,and threshold tracking examination were performed on the severe side;while in control group,the median motor nerve conduction examination and threshold tracking examination were performed on either side.We evaluate the changes in peripheral motor nerve conduction of Hirayama disease by comparing CMAP(compound muscle action potential)and median motor nerve conduction velocity evaluate the changes in motor nerve excitability by comparing the rheobase,SDTC(Strength-duration time constant),threshold electrotonus,current-threshold I/V slope,superexcitability,and subexcitability.The upper limb function was assessed by disabilities of arm,shoulder and hand(DASH)score.The differences in threshold tracking parameters between groups were compared by independent t test,and the correlation between SDTC and DASH score was tested by Pearson correlation analysis.Results In the peripheral motor nerve conduction examination,the median nerve CMAP in patients with Hirayama disease was 4.12±1.43 mV in average,which is lower than healthy controls 8.23±1.61 mV(t=-3.8,P<0.01).There was no significant difference in the peripheral motor nerve conduction velocity(t=-0.86,P=0.39).In the threshold tracking examination,SDTC in patients with Hirayama disease was 0.48±0.09 ms,which was prolonged than healthy controls 0.39±0.06 ms(t=3.75,P<0.01).The absolute values of TEh(10-20)and TEh(20-40)decreased significantly(P<0.01),hence,the hyperpolarized part of the threshold-electrotonus curve showed "fanning-in" pattern.The slope of the current-threshold(I/V)curve had a decreasing trend.The hyper-polarized l/V slope in patients with Hirayama disease was 0.27±0.09 in average,which was lower than the healthy controls which was 0.34±0.07(t=-2.73,P=0.01).The DASH score of patients ranged from 0.86 to 19.44,with an average of 6.99±5.79.There was a correlation between SDTC and DASH score,R2=0.36,which met the F test(P=0.01).Conclusion Threshold tracking technique can be adapted in evaluating nerve injury in Hirayama disease to determine the degree of injury and potential pathogenesis.%目的 探讨阈值追踪技术评估平山病患者神经损害的可行性.方法 2017年6月至2017年10月在华山医院骨科就诊的17例平山病患者纳入研究(平山病组),男16例,女1例;年龄16～22岁,平均(18.06±0.50)岁;病程1～60个月,平均(27.2±18.81)个月.同时纳入健康志愿者20名,男19名,女1名;年龄17～23岁,平均(20.05±1.30)岁.所有平山病患者选取症状严重侧上肢行正中神经传导检测、针肌电图检查及阈值追踪检查;同时,健康志愿者选取任意一侧上肢正中神经进行神经传导检测及阈值追踪检查以作为正常对照(正常对照组).通过比较复合肌肉动作电位(compound muscle action potential,CMAP)波幅、正中神经运动传导速度评估平山病患者神经传导的改变,通过比较基强度、强度-时程时间常数(strength-duration time constant,SDTC)、阈值电紧张相关参数[包括TEd(10～20)、TEd(90～100)、TEh(10～20)、TEh(20～40)、TEh(90～100)及S2相适应电流阈值(S2 accommodation)]、电流-阈值曲线斜率、超常期阈值、低常期阈值等评估平山病患者神经轴突的损害情况,采用上肢功能障碍评定量表(disabilities of arm,shoulder and hand,DASH)评分评估患者上肢功能.两组间比较采用独立样本t检验,Pearson相关性分析检验SDTC与DASH评分相关性.结果 相对于正常对照组,平山病组患者正中神经CMAP的平均波幅为(4.12±1.43)mV,明显低于正常对照组(8.23±1.61)mV(t=-3.8,P<0.01).SDTC平均为(0.48±0.09)ms,较正常对照组(0.39±0.06)ms明显延长(t=3.75,P<0.01).TEh(10-20)及TEh(20～40)的平均值分别为-70.36%±5.11%和-88.97%±7.94%,正常对照组则分别为-75.48%±5.68%和-96.88%±6.72%,其绝对值减小值的差异有统计学意义(P<0.01),阈值电紧张曲线的超极化部分呈明显"扇形收缩"("Fanning-in");电流-阈值曲线斜率有减小趋势,其中超极化电流-阈值斜率平均值为0.27±0.09,较对照组(0.34±0.07)明显减小(t=-2.73,P=0.01).平山病组患者DASH评分为0.86～19.44分,平均(6.99±5.79)分.SDTC与DASH评分之间有相关性,R2=0.36,满足F检验(P=0.01).结论 阈值追踪技术是评估平山病患者神经损害的可行方法,可用于评估病情严重程度以及探讨神经损害机制.
