周围神经损伤MCV测定及其法医学意义

目的探讨周围神经损伤后运动神经传导速度(MCV)改变与靶肌肌力级别的相关性。方法 60例病程6个月以上的单侧肢体神经损伤(正中神经12例、尺神经13例、桡神经13例、腓浅神经12例、腓深神经10例)患者,根据Lovett肌力0～5级分级标准,确定受损神经支配的靶肌的肌力;采用DNI-200+型肌电诱发仪行患侧与健侧肢体MCV检查,观察不同级别肌力靶肌MCV指标变化。结果所测5种神经MCV各指标(健侧-患侧)/健侧变化率均与靶肌肌力呈逐渐降低的变化趋势,存在显著负相关性,其中波幅和面积下降率在肌力2级与3级、4级与5级组间存在显著性差异(P<0.05)。潜伏期延长率和传导速度下降率在肌力1级与2级、4级与5级组间存在显著性差异(P<0.05)。结论 MCV与周围神经损伤有较好的相关性,可用于推断神经受损程度,并有助于肌力级别的判定,是评价周围神经损伤程度的客观方法。

A study on evaluation of peripheral nerve injury by MCV measurement in clinical forensic medicine

Objective To evaluate the correlation between motor conduction velocity(MCV) and the strength grade of the examined muscles after peripheral nerve injury.Methods According to Lovett ’s standards of 0 to 5 grading muscle strength,the strength of target muscles was determined among 60 patients with unilateral limb nerve injury over 6 months after injury(12 cases of median nerve,13 cases ulnar nerve,13 cases radial nerve,12 cases superficial peroneal nerve,and 10 cases deep peroneal nerve).4 paprameters including amplitude,area,conduction velocity and latency period in MCV for healthy and injured limbs were performed by DNI-200+ evoked potential motor to observe the change of MCV in the targeted muscles with different strength.Results There were significant negative correlation between ratios of(healthy limbs-morbid limbs) / healthy limbs in 4 MCV parameters of the five types of nerve injuries and the muscle strength of the injured muscles,which both tended to decrease.Decrease in the ratios of amplitude and area showed significant difference(P<0.05) between the injured muscles with grade 2 and 3,or grade 4 and 5 muscle strength.The ratio of extended latency period and the ratio of delayed conduction velocity showed significant difference(P<0.05) between the injured muscles with grade 1 and 2,or the grade 4 and 5 muscle strength.Conclusions MCV is correlated with peripheral nerve injury,which can be used to predict the severity of nerve injury and may be helpful for estimation of muscle strength,and is an objective method for evaluation of the severity of peripheral nerve injury.