Experiment Studying Of "Accordion" Technology For Treating Rabbit Tibial Nonunion

Objectives To establish the model of the atrophic nonunion,to analyze the parameters of the “Accordion” Technology,inciuding the parameters of intermittent period and the parameters of distraction range,and to explore the best combination of parameters of intermittent period and the parameters of distraction range which are favorable for turning atrophic nonunion to healing,and to provide the experimental basis for the clinical treatment of the nonunion of the “Accordion” Technology.Methods 38 male New Zealand Rabbits participate in the study,while eleven rabbits were excluded from the beginning to the end of the experiment for various reasons.Three of which were sacrificed to dissecting the tibia,others were osteotomied at the middle of the tibia,scraped the medullary cavity,circumresected the outer periosteum,reducted the osteotomy bone ends,installed the external fixator which could distraction and compression,left 3mm bone space to establish atrophic nonunion model.After 10 weeks,the model of atrophic nonunion was confirmed by X-ray and CT.Two of which were randomly selected for harvesting the nonunion specimens to observe the histomorphology of nonunion.The left rabbits were randomly divided into two groups: “Accordion”Technology and Simple Compression Technology,the former were randomly divided into4 groups based on random combination of the parameters of intermittent period(0 days,6days)and the parameters of distraction range(4mm,6mm),namely,A1B1 group(0 days,4mm),A1B2 group(0 days,8mm),A2B1 group(6 days,4mm),A2B2 group(6 days,8mm).And then 0.34 mm / time,2 times a day of “Accordion” Technology and Simple Compression Technology were carried out respectively.Animals were sacrificed respectively at 6 weeks after ending all treatment modalities.Utilizing X-ray and HE staining to observe the healing progress of all nonunion;taking advantage of Micro-CT related detection indicator-Tone Mineral Content Index(TMCD),Tone Mineral Density Index(TMDD)and Bone Volume Fraction Index(BVFD)to quantitative analyze and compare “Accordion” Technology and Simple Compression Technology.The data were analyzed by SPSS21.0 statistical analysis software.Results 1 All the tibial radiographs,CT and HE staining demonstrated the atrophic changes of osteotomy bone ends;2 HE staining and X-ray results showed Significant differences between “Accordion” Technology and Simple Compression Technology,as well as four groups of “Accordion” Technology;3 The TMCD,TMDD and BVFD of the“Accordion” Technology group were higher than that of the Simple Compression Technology group,the difference was statistically significant;4 Micro-CT related detection indicator of TMCD,TMDD and BVFD was used to dectected the difference among the Accordion” Technology models with different parameters of intermittent period and the parameters of distraction range combination.It turns out that the A1B2 group had the highest index and the A2B1 group had the lowest index.As the parameters of intermittent period was compared as the variable,P <0.05,namely,the difference from the parameters of intermittent period was statistically significant,so did the parameters of distraction range.But the exploration of interactive effects among the parameters of intermittent period and the parameters of distraction range showed P>0.05,it was no statistically significant.Conclusion 1 The atrophic nonunion model of rabbit tibia was successfully established;2 “Accordion” Technology could treat rabbit tibia atrophic nonunion effectively;3 Increasing the parameters of distraction range and cutting down the parameters of intermittent period are conducive to nonunion healing;This experiment shows that the "Accordion" Technology model with 0d and 8mm for the treatment of nonunion is the most effective;4 There is no interaction between the parameters of intermittent period and the parameters of distraction range.