An Experimental Study On The Improvement Of Ilizarov Transverse Tibial Bone Transport And Microcirculation Reconstruction Technique

Objective:To observe the effect of traditional and modified Ilizarov transverse tibial bone transport on microvascular regeneration of lower limbs in dogs.Methods:After general anesthesia on 10 experimental dogs,traditional and modified transverse tibial bone transport were performed on both tibias respectively.The control group was treated with the traditional method（the periosteum and bone flap were completely isolated）,while the experimental group was treated with the modified method（the fibular periosteum of the open window bone flap was retained）.All were pulled outwards at a speed of 1 mm every day from 5 days after operation.After one week,all were moved back every 3 days for one week.The situation of wounds and activity of lower limbs were observed.Simultaneously,the angiogenesis was observed by digital subtraction angiography（DSA）through femoral artery at different stages,and the density of vascular endothelial cells measured by local tissue sections.Results:The operation was successfully completed in 10 experimental dogs,and all wounds healed about 1 week after operation.There was no significant abnormality in lower limb movements in all dogs.Peripheral blood vessel area in middle leg of lower limb DSA:The blood vessel area in 4 weeks and 8 weeks after operation was（5.9?0.4）^mm2 and（6.9?0.6）^mm2 in control group respectively.In the experimental group,the blood vessel area in 4 weeks and 8 weeks after operation was（6.2?0.6）^mm2 and（8.0?0.6）^mm2 respectively.All were significantly improved than that of pre-operation[control group（5.0?0.4）^mm2,experimental group（4.9?0.4）^mm2,t=0.109,P=0.915].But there was no significant difference in vessel area between the two groups at 4 weeks after operation（4.9?0.4）^mm2（t=1.216,P=0.240）.The statistical significance difference was found in the vascular area between the two groups at 8 weeks after operation（t=4.423,P=0.000）.Hematoxylin-eosin（HE）staining was performed on the transported region and dorsal foot tissue respectively at 8 weeks after operation.The percentage of vascular endothelial cells in stained cells under endoscopy was（4.42?0.28）%and（5.63?0.53）%respectively in the control group.In the experimental group,the percentage was（5.35?0.26）%and（7.18?0.25）%.All were increased than that in the preoperative[transported region:control group（3.74?0.20）%and experimental group（3.68?0.15）%;dorsal foot region:control group（4.95?0.42）%and experimental group（5.16?0.41）%].The difference was statistically significant（t=7.35,t=8.30,P=0.00）.Conclusion:Transverse tibial bone transport and microvascular network regeneration technology can reconstruct the microvasculature below the calf of dogs.The method of window-opening osteotomy is improved to"door"type window-opening.Compared with traditional"rectangular"window-opening method,it can retain the lateral periosteum of tibial crest and regenerate the microvasculature network more abundantly.This study provides experimental basis for optimizing this technology for the treatment of lower limb ischemia in clinic.