Utilization of motor evoked potentials for the intraoperative spinal cord monitoring-study on the prevention and fixation of the spinal cord injury

近年来，通过运动相关束传递的电位已被提倡用于术中脊髓监测。特别是使用复合肌肉动作电位（CMAP）被认为是监测运动功能的最佳信息，尽管我们必须提醒实际使用者注意CMAP的潜在问题。它们是1。2.麻醉的效果与消除；与CMAP超敏相关的问题，即CMAP消失与术后运动功能之间的差异，2。CMAP对脊髓损伤超敏反应的生理机制探讨。我们可以证明，间隔1-2msec刺激2 ~ 5个序列可以消除吸入麻醉物质对前运动神经元的影响。此外，我们可以证明CMAP的消失并不直接表明运动功能受损。在另一个病房，尽管CMAP对脊髓轻微损伤的反应幅度下降，但动物醒来时没有任何神经后遗症。进一步的损伤会使传导电位如SCEP（脊髓诱发电位）和MEP（脑刺激后脊髓记录的运动诱发电位）减少50%左右，导致动物运动瘫痪的发生率很高。基于上述结果，我们建议CMAP与导电电位同时使用。CMAP超敏反应的机制有待进一步研究。

In recent years, potentials delivered through the motor related tracts have been advocated for the intra-operative spinal cord monitoring. Especially the use of the compound muscle action potential (CMAP) has been regarded to offer optimal information to monitor the motor function, although, we have to call attention of the practical users to the potential problems with CMAP.They are 1. Effect and elimination of anesthesia, 2.Problems related to the hypersensitivity of CMAP that means the discrepancy between the CMAP disappearance and postoperative motor ysfunction, 3. Understanding of the physiological mechanism of the hypersensitivity of CMAP against the insults to the spinal cord. We could show the use of stimulation of 2 to 5 trains with 1-2msec interval could eliminate the effect of inhalation anesthetic substance on the anterior motor neurons. Furthermore, we could demonstrate that the disappearance of CMAP is not directory indicate the impairment of the motor function. In another wards, despite CMAP decrease in amplitude responding to the slight insult to the spinal cord the animal woke up with any neurological sequela. Further insult which produced around 50% decrement of the conductive potentials such as SCEP (spinal cord evoked potential) and MEP (motor evoked potential recorded from the spinal cord after the brain stimulation) left high incidence of motor paralysis in animals. On the basis of above mentioned results, we recommend the concomitant use of CMAP with conductive potentials. The mechanism of the hypersensitivity of CMAP has been left for future study.