腕管综合征术前、后感觉神经动作电位与复合肌肉动作电位检测结果的比较

目的　比较腕管综合征术前和正中神经松解术后 (术中 )两者感觉神经动作电位 (sensorynerveactionpotential ,SNAP)与复合肌肉动作电位 (compoundmuscleactionpotential,CMAP)检测结果的差异。方法　对 2 0例腕管综合征患者 ,术中在切开屈肌支持带及正中神经松解术后 ,分别测定 (1)拇短展肌的CMAP ;(2 )刺激示、中指 ,于腕部记录正中神经的SNAP ;(3 )刺激环指 ,于腕部分别记录正中神经和尺神经的SNAP。将三者结果与术前的相应数据行统计学分析。结果　 (1)术前拇短展肌CMAP的潜伏期小于4 3ms ,术后其潜伏期、波幅与术前相比差异无统计学意义 (P >0 0 5 )。 (2 )术后 2～ 4指SNAP的潜伏期比术前平均缩短 5 %、波幅增加 13 %左右 ,两者相比差异均有统计学意义 (P <0 0 1)。结论　腕管综合征手术中 ,在正中神经松解术后行SNAP检测较CMAP检测的结果更为敏感和准确。

Comparison of SNAP and CMAP before and after carpal tunnel release: a clinical study

ObjectiveChanges of SNAP (sensory nerve action potential) and CMAP (compound muscle action potential) following carpal tunnel release and median nerve decompression were investigated to evaluate the sensitivity of these electrophysiologic parameters and their clinical significance.Methods20 patients with carpal tunnel syndrome were involved in the study. Electrophysiologic examination was carried out to record the following parameters: CMAP of abductor pollicis brevis muscle, SNAP of the median nerve at the wrist when the index and middle fingers were stimulated, and SNAP of the median nerve and ulnar nerve at the wrist when the ring finger was stimulated. These parameters were recorded before the operation (pre op) and 10 minutes following carpal tunnel release and median nerve decompression (immediately post op). Student t test was applied to compare the pre op and post op changes of these parameters.ResultsThere were no statistically significant differences between the latent periods and amplitudes of abductor pollicis brevis CMAP recorded pre operatively and those recorded immediately post operatively. There were, however, significant changes in SNAP recorded by stimulating the index, middle and ring fingers. The latent periods of SNAP were shortened by 5% on average after carpal tunnel release, while the amplitudes were increased by 13%. The differences between the pre operative levels and post operative levels were of statistic significance.ConclusionComparing to CMAP, SNAP is a more sensitive and accurate parameter in evaluating the effectiveness of carpal tunnel release and median nerve decompression.