周围神经术前肌电图结果与术中所见的比较研究及误诊原因分析

目的 探讨肌电图(EMG)检查对周围神经损伤的诊断意义，分析误诊的原因。方法 收集2000年1月至2003年4月行手术治疗的周围神经损伤患者63例(69条神经)，按神经损伤特点分为开放性周围神经损伤组、闭合性周围神经损害组、臂丛损伤组和神经修复后再生组，各组患者均于术前进行肌电图检测，并将检测结果与术中所见进行比较、分析。结果 开放性周围神经损伤组术前EMG对神经完全损伤的诊断符合率为73.08％，与术中所见结果比较，差异有统计学意义。闭合性周围神经损害组对受损神经的定性、定位诊断，均在术中得到证实。臂丛损伤组的大体定位正确率达96．30％，完全符合率达70．37％；对臂丛完全根性损伤的检出率为68．52％，与磁共振的检出率(55．56％)相比，差异无统计学意义。神经修复后再生组5条神经，EMG结果与术中所见3条符合，2条不符合。69条神经中，EMG检查完全符合率为71.01％，基本符合率为85．51％，完全不符率为13．04％；假阳性率为4．49％，假阴性率为22．73％。结论 EMG检查对损伤神经的定位、定性诊断及神经修复后再生状况的评价在临床诊治中具有重要的指导意义，但可出现假阳性及假阴性结果，且以运动诱发电位的假阴性为多。术前EMG与磁共振检查相结合，可提高对臂丛神经完全根性损伤的检出率。

A comparative study of electromyogram and the findings on operation in patients with peripheral nerve lesions

Objective To evaluate the clinical value of preoperative EMG examinations in diagnosis of peripheral nerve injury and to analyze the reasons of misdiagnosis. Methods From January 2000 to April 2003, the results of electrophysiological examinations of 69 nerves in 63 inpatients for operation were compared with the findings on operation. Results In the open injury group, the diagnostic accuracy rate of EMG was 73.08%, which was significantly different from the findings on operation. In the close injury group, the location and quality of injury as diagnosed by EMG examination were all confirmed on operation. In the brachial plexus injury group, the diagnostic accuracy rate for complete root avulsion was not significantly different from that of MRI (68.52% vs 55.56%). With regard to the evaluation of axon regeneration after repair operation of peripheral nerve injuries, EMG examinations of 3 nerves were consistent with the operative findings, while 2 nerves in 5 nerves were not. The general diagnostic accuracy rate of EMG examinations of peripheral nerve lesions was 85.51%. The false positive rate was 4.49%, while the false negative rate was 22.73%. Conclusion EMG is valuable in detecting the location, characteristics and axon regeneration in patients with peripheral nerve injury. But the false positive and false negative results should be watched out. There is no statistical significant difference between preoperative EMG and MRI in detecting the complete brachial plexus root avulsion. A combinative use of EMG and MRI can improve the diagnostic accuracy of brachial plexus roots injuries.