Maertens de Noordhout A, Rothwell J C, Thompson P D, Day B L, Marsden C D
University Department of Neurology, Institute of Psychiatry, London, UK.
J Neurol Neurosurg Psychiatry. 1988 Feb;51(2):174-81. doi: 10.1136/jnnp.51.2.174.
High voltage percutaneous electrical stimulation over the lumbosacral spinal column was used to assess conduction in the cauda equina of 13 normal subjects. Electromyographic activity elicited by such stimulation was recorded from various muscles of the lower limbs. The stimulating cathode was placed over the spinous process of each vertebral body and the anode kept on the iliac crest contralateral to the studied limb. Shifting the cathode in a rostro-caudal direction shortened the response latency in quadriceps, tibialis anterior and extensor digitorum brevis muscles. At moderate intensities (60% maximum), this occurred abruptly when the cathode was placed at levels corresponding to the exit sites from the spinal canal of the roots innervating these muscles. At these intensities, the size of the response in each muscle was largest when the cathode was placed over the conus medullaris or at or below the exit of the motor roots from the spine. Latencies were always equal to or shorter than those obtained with F-wave measurements, suggesting that peripheral motor axons, rather than intraspinal structures were activated by the stimulus. Collision experiments demonstrated that activation occurred at two sites: near the spinal cord and at the root exit site in the vertebral foramina. Recordings made from soleus indicated that larger diameter proprioceptive afferent fibres also could be activated. This technique might have useful clinical applications in the study of both proximal and distal lesions of the cauda equina and provide a non-invasive method of localising such lesions electrophysiologically.
采用腰段脊柱的高压经皮电刺激来评估13名正常受试者马尾神经的传导情况。通过这种刺激诱发的肌电活动记录自下肢的不同肌肉。刺激阴极置于每个椎体的棘突上，阳极置于与所研究肢体对侧的髂嵴上。在头尾方向移动阴极可缩短股四头肌、胫骨前肌和趾短伸肌的反应潜伏期。在中等强度（最大强度的60%）时，当阴极置于与支配这些肌肉的神经根从椎管出口相对应的水平时，反应潜伏期会突然缩短。在这些强度下，当阴极置于脊髓圆锥上方或运动神经根从脊柱出口处或下方时，每块肌肉的反应幅度最大。潜伏期总是等于或短于通过F波测量获得的潜伏期，这表明刺激激活的是外周运动轴突，而非脊髓内结构。碰撞实验表明激活发生在两个部位：脊髓附近和椎间孔的神经根出口处。比目鱼肌的记录表明，直径较大的本体感觉传入纤维也可被激活。这项技术在马尾神经近端和远端病变的研究中可能具有有用的临床应用价值，并提供一种通过电生理方法定位此类病变的非侵入性手段。
