Magnetic Stimulation for Increasing the Tolerance to Ischemic Change of Spinal Cord ; Prevention of Risk of Paralysis Secondary to Operation

术后下肢轻瘫是主动脉瘤手术治疗后的严重并发症之一。这种复杂情况的主要原因被认为是脊髓局部循环障碍。在一些关于脑缺血的报道中，有研究表明磁刺激具有抗缺血作用。如果有可能类比脑的应用来替代减少的脊髓循环，这将对主动脉瘤手术患者有很大的帮助。在此假设下，我们进行了一系列实验，以确认磁刺激是否可以增加动物模型对脊髓缺血性变化的耐受性。1.在大鼠中，通过将球囊导管插入主动脉，暂时关闭脊髓循环，然后充气。用粗大运动功能测试评定神经功能缺损程度。运动功能测试结果改变 ...更多信息 2.分别于麻醉前、麻醉中、麻醉后3个月内，3.刺激组动物经球囊导管预处理后，在MEP连续监测下，阻断主动脉循环10 min，磁刺激脊髓靶区（Th 11-L3）。对照组在相同的监测条件下只关闭10 min，刺激组与对照组MEP反应不同。电刺激组切断时间后MEP波幅较切断时间前增大。对照组MEP在阻断后较阻断前明显降低。MEP监测的脊髓神经生理功能显示，磁刺激预处理前后脊髓对暂时性缺血的反应不同，这一结果还需进一步的组织学改变或生化指标来证实。磁刺激引起的组织反应的数据还需要进一步积累，除了这些脊髓刺激的动物实验外，还获得了关于脑磁刺激对自主神经系统特别是血压和心率的3周影响的衍生发现。少

Postoperative paraparesis is one of the serious complications after operative treatment for aortic aneurysm. A main cause of this complicated condition is regarded as disturbance of local circulation of the spinal cord. In a few reports about brain ischemia there are findings to indicate resistant effect against ischemia by magnetic stimulation. If there is a possible application by analogy with brain to substitute decreased spinal cord circulation, it could be a great help for the patient with operation for aortic aneurysm. Under this hypothesis we have performed a series of experiments in order to confirm whether magnetic stimulation could increase the tolerance to ischemic change of spinal cord in animal model or not.1.In a rat the spinal cord circulation was temporarily shut off by means of a ballooned catheter inserted into the aorta and then inflated. The degree of neurological deficit was assessed with gross motor functional test. The result of motor functional test was changeab … More le according to the duration of shut off time.2.Motor evoked potential(MEP) at the gastrocunemius muscle by transcranial magnetic stimulation(TMS) was continuously monitored before, during, and after aortic circulation shut off by inflation and deflation of the ballooned catheter.3.In stimulation group the animals under continuous monitoring with MEP measurement experienced 10 min shut off of the aortic circulation after the preconditioning by magnetic stimulation for the targeting area of spinal cord (Th11-L3). In control group the animals with same monitoring had 10 min shut off only.There was different response of MEP between in stimulation group and in control group. The amplitude of MEP after shut off time was bigger than before in stimulation group. On the contrary that of MEP after shut off time was smaller than before in control group. Neurophysiological function of the spinal cord monitored in MEP measurement revealed different response against temporary ischemia with or with out preconditioning by magnetic stimulation.These findings should be confirmed by other data like histological changes or biochemical assessment. Further accumulation of data on tissue responses caused by magnetic stimulation will be needed in future.Apart from these animal experiments with spinal cord stimulation, a derivative finding on 3-weeks effect of magnetic stimulation at brain to autonomic nerve system especially blood pressure and heart rate was obtained. Less