| PrefaceThe complexity, danger and even complications of the operational therapy of thoracoabdominal aortic aneurysm (TAAA) are more than those of abdominal aortic aneurysm. Many vascular surgeons have delivered their effort to the therapy of the disease and great developments have been obtained. Although in the recent 30 years, the morbidity of the operation has decreased apparently, as a complication, the spinal cord injury (SCI) is always severe, unexpectable and disastrous. According to some reports, the occurrence of post - operative paraplegia and paralysis is 3% to 38% . The main cause of paraplegia is the per-fusion shortness of spinal cord, and to lighten the SCI, many auxiliary devices and methods have been applied, but none of them can offer definitive and complete protection. Here, the animal experiment has shown that the maintenance of spinal cord perfusion pressure can confirm the perfusion of spinal cord to lighten SCI. The modified Hardy applied in the No. 1 clinical hospital of China Medical University to repair TAAA can confirm the distant mean arterial pressure ( MAP)during and after the operation, and bring no severe SCI. To confirm the preventive action of the modified Hardy against SCI, an animal model experiment was performed to evaluate its effect on spinal cord function by analyzing the relationship of SCPP, spinal cord perfusion, Neural function and pathological change.Minerals1. Agents and minerals: blood vessel prosthesis of terylene, ex-tradural anaesthesia device, 10% neutral formaldehyde, alcohol, toludine blue, etc.2. Apparatus; vascular surgery instrument, multipurpose polygraph, pressure transducer, laser tissue perfusion monitor, light microscope, camera, etc.3. Experiment animals: 15 healthy hybrid canines, no matter a-bout sex, with weight 22. 5 2. 5kg and age 12-18 months.Methods1. Setup of animal models; The 15 hybrid canines were divided into normal control group, experiment group (namely the group accepted the modified Hardy) and Interruption group, which were 1,8, 6 respectively. In the experiment group (Hardy group) , blood vessel prosthesis bypass from the base of celiac artery to the part beneath the kidney was performed, and the mesentery artery and the left renal artery were anastomosed with the corresponding branches of manual vessel. In the interruption group ( aorta interruption group) , the aorta, the beginning part of the celiac artery and the mesentery artery weredissociated. In the two above groups, the indwelling binders were placed at the close end of mesentery artery and the occlusion duration was 35 minutes. In the normal control group, only anesthesia , celiot-omy and aorta dissociation were performed.2. Experimental index determination; ( 1 ) SCPP and SCBP determination ; In the experiment group, SCPP and SCBP were measured respectively before the opening of blood vessel prosthesis shunt and after the opening with aorta occlusion. In the Interruption group, SCPP and SCBP were measured before and after the aorta occlusion. (2) Neural function evaluation; Two weeks after the operation, the Hind-limb muscle strength of all the experiment animals were blind estimated by the two observers according to the Tarlove's scale, and the mean was also measured. The detailed grades are as follows; grade 0; convulsive paraplegia; grade 1; convulsive paraplegia with slight movement of Hindlimb muscle; grade 2; good movement of Hindlimb muscle , but incapable of standing; grade 3 ; step dysfunction although capable of standing; grade 4; complete recovery and normal movement. (3) The spinal cord histopathology: In the 14th day after the operation, all the animals' L3 segment spinal cord were taken under anesthetic state, and were made 6uM paraffin slices stained by HE, and toludine blue (Nissl body). The histopathological changes were observed under light microscope.3. The statistic analysis; All the measured values were analyzed by the SPSS10. 0 statistic soft, and apparent differences were conside...
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