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

术后瘫痪是主动脉瘤手术治疗后的严重并发症之一。这一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，有发现表明磁刺激具有抗缺血作用。如果有可能用类比脑来替代脊髓循环减少，对主动脉瘤手术患者有很大的帮助。在这一假设下，我们进行了一系列的实验，以证实磁刺激是否可以提高动物模型对脊髓缺血性改变的耐受性。1.在大鼠中，通过将气囊导管插入主动脉并充气来暂时切断脊髓的循环。用粗大运动功能测试评定神经功能缺失程度。运动功能测试结果为…2.经颅磁刺激(TMS)在气囊导管充气放气阻断主动脉循环前、中、后持续监测腓肠肌运动诱发电位(MEP)。3.刺激组在脊髓靶向区(T11-L3)磁刺激预适应后，持续监测MEP，阻断主动脉循环10min。对照组相同监测的动物仅停机10min，刺激组与对照组的MEP反应不同。电刺组关机后MEP波幅较关机前增大。而对照组停机后MEP明显低于停机前。MEP监测的脊髓神经生理功能在磁刺激和无预适应的情况下对短暂性脑缺血的反应不同，这一结果需要通过组织学变化或生化评估等其他数据来证实。关于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，关于脑内磁刺激对自主神经系统，特别是血压和心率的3周效应的派生发现。较少

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