Establishment Evaluation And Applications Of Different Levels Of Permanent Spinal Cord Ischemia Animal Models

Objective:Different levels of permanent spinal cord ischemia animal models were established through the study of the anatomy and physiology.The value of TceMEP during the surgery of intramedullary spinal-cord tumor was studyed.Methods:Part 1 Anatomical related research:Experiment 1: Anatomy of shaping:After the whole bodys were perfused and fixed in 10 newzerland rabbits,the latex rubber were perfused through the descending aorta.The lumbar artery were obsered 1 days after that. Experiment 2 (n=12):The Colored Latex rubber was Perfused through the single lumbar artery.The anterior spinal artery and the blood supply region was studied and obsered. Part 2 The establishment and scientific assessment of different levels of permanent spinal cord ischemia animal models:33 newzerland rabbits were randomly divided into 6 groups,with 8 rabbits in the control group and with 5 rabbits at each experiment group. Transcranial electrical stimulation motor evoked potentials were recored at different time:before Vascular ligation, 30 minutes after vascular ligation, 2 days after vascular ligation.Motor function were assessed after narcotic conscious and 2 days after vascular ligation.The specimens were taken 2 days after ligation. Part 3 Prevention of SCII by intraoperative TceMEP monitoring:an experimental study:16 rabbits were randomly divided into 4 equal groups(n=4).The control group underwent only sham operation without SCI(spinal cord injury), The EPs were recorded before and after the operation and at different time points after the rabbits were anesthetized.The other 3 groups underwent median abdominal approach for segmental spinal artery ligation. The TceMEPs were recorded within 5 minutes after the amplitude stability. Motor function was asessed after anaesthesia conscious and 2 days after ligation.The spinal cords were removed for histologic examination.Results:Part 1 The lumbar artery of rabbit is chevron's,which is convenient for ligation;2,The characteristic of cross-regional and the role of collateral of Spinal cord blood supply.Part 2 1,2 ligation will not cause ischemic spinal cord injury,There were no significant differences,Before and after ligation,P>0.05;Different levels of spinal cord ischemia animal models can be made by the ligation of 3,4,5 levels of lumbar artery.Part 3 The amplitude are more sensitive than latency to spinal cord ischemic damage. The amplitude is stable within 5 minutes after spinal cord ischemia.The amplitude changes of early and reversible stage is positive relationship with motor function of"Wake-up test"and 2 days after ligation r=0.977,r=0.933,p<0.001. The amplitude changes of early and reversible stage is positive relationship with Pathological damage,r=0.971,p<0.001.Conclusion: Animal model of spinal cord ischemia can be made by the ligation of different levels of lumbar artery between the left renal artery and arterial bifurcation. TceMEP is sensitive to spinal cord ischemia damage. Spinal cord ischemic injury can be detected in an early and reversible stage with TceMEP monitoring intraoperative.The irreversible spinal cord injury can be prevent timely.