Machida M, Yamada T, Ross M, Kimura J, Hitchon P
Department of Orthopaedic Surgery, Nihon University School of Medicine, Tokyo, Japan.
J Spinal Disord. 1990 Dec;3(4):345-52.
We recorded the compound muscle action potentials (CMAP) from the soleus muscle and spinal evoked potentials (SpEP) from the caudal spinal cord after stimulation of the rostral spinal cord via epidural electrodes in 18 dogs. We examined the changes of CMAP and SpEP after the cord was made ischemic by clamping the aorta at different levels. Clamping the abdominal aorta below the artery of Adamkiewicz (five dogs) did not change either CMAP or SpEP significantly. When the thoracic aorta was clamped above the radicular and Adamkiewicz arteries (10 dogs), CMAP disappeared entirely within 5-10 min of occlusion, but SpEP showed only minimal latency prolongation limited to the late peaks in seven of 10 dogs. In the remaining three dogs, both CMAP and SpEP disappeared within 30 min of occlusion but with the more rapid deterioration of CMAP than of SpEP. Progressive ligation of lumbar arteries (three dogs) from caudal to rostral levels did not change CMAP until ligation of Adamkiewicz artery. Then CMAP disappeared, but SpEP remained unchanged. These findings suggest that CMAP and SpEP are mediated through different pathways and that CMAP reflect anterior cord function. The described electrophysiologic technique would be useful to monitor spinal cord motor function during surgery of the spine, spinal cord, or thoracoabdominal aorta.
我们在18只犬中，通过硬膜外电极刺激脊髓头端后，记录了比目鱼肌的复合肌肉动作电位（CMAP）和尾段脊髓的脊髓诱发电位（SpEP）。我们在不同水平夹闭主动脉使脊髓缺血后，检查了CMAP和SpEP的变化。在Adamkiewicz动脉以下夹闭腹主动脉（5只犬），CMAP和SpEP均无明显变化。当在根动脉和Adamkiewicz动脉上方夹闭胸主动脉时（10只犬），CMAP在闭塞后5 - 10分钟内完全消失，但在10只犬中的7只，SpEP仅表现为最小潜伏期延长，仅限于晚期峰值。在其余3只犬中，CMAP和SpEP在闭塞后30分钟内均消失，但CMAP的恶化比SpEP更快。从尾端向头端逐步结扎腰动脉（3只犬），在结扎Adamkiewicz动脉之前CMAP无变化。然后CMAP消失，但SpEP保持不变。这些发现表明，CMAP和SpEP是通过不同途径介导的，且CMAP反映脊髓前侧功能。所描述的电生理技术在脊柱、脊髓或胸腹主动脉手术期间监测脊髓运动功能方面将是有用的。
