【摘要】 目的:探讨受损神经容积传导对靶肌复合肌动作电位(CMAPs)检测的影响。方法:制备大鼠坐骨神经钳夹伤模型,在钳夹段远侧及近侧不同位置,采用不同强度刺激坐骨神经,记录胫前肌CMAPs,比较不同条件下CMAPs振幅大小。结果:当刺激钳夹段近侧3 mm处坐骨神经时,需要强度3 mA以上才能记录到最大振幅的CMAPs,且近侧神经上刺激点距钳夹段越远,引出胫前肌CMAPs所需刺激强度就越大;用强度0.3～0.5 mA依次刺激钳夹段远、近侧神经,前者可记录稳定的CMAPs,而后者未能记录到。结论:容积传导呈明显衰减特点,过强的刺激可能导致对神经损伤的漏诊,因此术中应用电生理方法判定神经损伤位置和程度时所采用的刺激强度应适中。更多还原

【Abstract】 Objective: This study was performed to determine the influence of volume conduction on electrophysiological assessment of nerve injury.Methods: In a model of acute sciatic nerve crush,compound muscle action potentials(CMAPs) were recorded in tibialis anterior muscle,by applying a set of electrical stimuli with varing intensity to different position of the nerve trunk proximal to crush.The peak amplitudes of CMAPs were measured for comparison among recordings under different condition.Results: Reproducible CMAPs,with maximal amplitudes,were recorded in tibialis anterior muscle when the nerve trunk distal to crush was electrically stimulated at an intensity of 0.3~0.5 mA,while no CMAPs were seen when stimuli of the same intensity were applied on the nerve trunk proximal to crush.Reproducible maximal CMAPs were recorded only with stimuli at intensity ≥ 3 mA when the stimulation site was moved to 3 mm proximal to the crush,and the longer distance proximal to crush,the stronger stimuli were required for recording CMAPs with maximal amplitudes.Conclusion: Although volume conduction exhibited rapid reduction during propagation along the nerve trunk,reproducible CMAPs could be induced by super-maximal stimulation which passively propagated across the crushed segment,thus optimal stimulation intensity was required for intra-operative electrophysiological assessment of the nerve fiber continuity and to locate an injury.更多还原