皮层体感诱发电位在不同水平脊髓缺血中的变化

目的 为术中应用皮层体感诱发电位(CSEP)监测脊髓功能,预防术后运动功能障碍提供理论依据. 方法 33只新西兰大白兔采用随机数字表法分为6组,对照组8只用于排除麻醉和手术对诱发电位的影响,余25只根据结扎左肾动脉和动脉分叉间节段性脊髓供血动脉的条数分为5组(n=5),分别为1～5根组.记录各组动物麻醉后基线诱发电位,血管结扎后急性期诱发电位,结扎后30 min、2 d后诱发电位.动物麻醉清醒后、血管结扎后2 d时进行运动功能评分,并取缺血中心区标本行HE染色. 结果 潜伏期对缺血性损伤不敏感,实验组与对照组差异无统计学意义(P>O.05);波幅变化复杂,对运动功能特异性差,2、3、4根组均观察到急性期波幅先降低又逐渐恢复趋势,波幅的变化可以反映脊髓的病理损害程度和运动功能. 结论 缺血急性期CSEP波幅变化复杂,对运动功能特异性差,波形记录的信号需要平均化过程,造成结果 解释的延迟,术中应联合运动诱发电位对脊髓功能进行监测.

Changes of cortical somatosensory evoked potentials under different levels of ischemia in the spinal cord

Objective To provide the theoretical basis for the application of cortical somatosensory evoked potential (CSEP) in monitoring the function of the spinal cord to prevent postoperative neurological dysfunction. Methods Thirty-three New Zealand rabbits were randomly divided into 6 groups: 8 were chosen as control group to eliminate the influence of anesthesia and surgery on the evoked potential; the other 25 were assigned to 5 sub-experimental groups (n=5) according to the artery number being ligatured in the left renal arteries and the spinal arteries. Baseline evoked potential in each group was noted immediately after anesthesia; the CSEP were recorded at different time points (before vascular ligation, 30 min and 2 d after vascular ligation). Motor functions were assessed after narcotic conscious and 2 d after vascular ligation. The specimens were taken for HE staining. Results The latency was not sensitive to spinal cord ischemia and no significant difference of that was found between the experimental groups and the control group (P>0.05); except that, the changes of theamplitudes were very complex and the specificity of motor function was decreased. The amplitude reduced and then gradually restored in the 2, 3 and 4 levels of ligation. The changes of amplitude could indicate the degree of pathological damage in the spinal cord and its motor function. Conclusion Complex amplitude of somatosensory evoked potential can be found in the acute phase of ischemia in the spinal cord. Specificity of motor function is poor resulting from its signal averaging process. Motor evoked potential monitoring in the operation should also be added in the detection of the spinal cord.