With The Rapid Establishment Of Adult Porcine Vertebral Similar Osteoporosis Biomechanical Model

Objective: Objective With the rising proportion of the world’s aging population,due to osteoporosis-related clinical disease caused by more and more,such as spondylolisthesis,vertebral fractures,scoliosis and proximal femur fractures due to osteoporosis caused of these diseases,the current choice of surgical approach most abroad of vertebroplasty balloon vertebroplasty or pedicle screw fixation,internal fixation through screw placement,These diseases have been serious harm to the elderly health and living conditions,increased the burden on society and famil.In the case of osteoporosis,due to loss of BMD of the vertebral body,the compression force generated when the external force to the spine,conducted through the disc to the vertebral endplate,to spread around the center of the trabecular bone, the stress is formed inside the vertebral body,once the stress exceeds the strength of trabecular bone can withstand,the trabecular structure will be destroyed,thus losing the stability of the vertebral body,the vertebral fracture will occur when the further development of the local crack.As a result of the vertebral body reduced bone mineral density,the trabecular thinning,often caused by the failure of the operation.The need to re-pedicle screw fixation surgery,the patient needs to be taken out of pedicle screws,the mechanical fixed strength of the spinal vertebrae may occur secondary to weaken leading the pedicle screw loose, fracture and displacement. Therefore,in case of the osteoporosis,how to improve the pedicle screw fixation effect is the concern topic of the scholars in recent years.With the deepening study of the osteoporosis,osteoporosis model applied more widely,especially the study of the biological mechanics model of osteoporosis.Currently the representative animal model of osteoporosis spine biomechanics studies most are castrated and female animals or medication animals,although these are considered the best model,but there are still many shortcomings,along with the tightintegration of the medicine,mechanics and materials science and other related disciplines,a variety of new bone filling material and new internal fixation devices are emerging,well selection and establish a more suitable osteoporosis large animal model is the key of we do clinical treatment and study the osteoporosis cause.Therefore, the correct selection and preparation of an ideal experimental animal models of osteoporosis,is the basis for the research work.Currently, the domestic and foreign experts are main use the decalcification method in vitro to build a model type of osteoporosis,the principle of this method is use the decalcification to reduce the bone mineral density,the amount of the bone loss, leading to the bone biomechanical properties of qualitative decline,provide a good platform for the study of the biomechanical of the vitro similar osteoporosis model,these methods shorten the modeling cycle,but there are still have problems,for example,the decalcification liquid standardization and the standardization of the decalcification device,we need further experimental study.So we need to provide a simple,rapid method for set up a similar osteoporosis animal model, use boiling method,rapid establishment of adult porcine vertebral similar osteoporotic biomechanical model and investigate a fast and effective preparation the vitro of similar osteoporosis vertebral biomechanical model of new method,provide a frame of reference for the biomechanical study in a real state of osteoporosis.Methods:Select 36 adult porcine thoracolumbar vertebral,after formaldehyde soaked divided into four treatment groups randomly,each group have 9 vertebrae,take four different treatment methods: A group(ie control group, not treated),B,C,D groups respectively at 100 ℃ boiling water boiled 1h,2h,3h,after measure its bone mineral density(BMD),observe its digital X-ray(DR),parallel biomechanical experiment:testing the maximum axial pull output(Fmax) and the maximum compressive strength and stiffness,with the time prolonged to observe the changes.Results:Group B,group C,and Group D of the BMD mean,the mean maximum axial pullout force and maximum compressive strength and stiffness were lower than those in group A(P <0.01),and in turn decrease with prolonged boiling time(P <0.01),and DR show:the boiled group of bone mass are decreased and the bone mineral density are lower significantly.Conclusions:Primary osteoporosis is a prone to fracture and systemic bone disease,and is characterized that reduced bone mass,bone tissue microstructure changes, cancellous bone trabecular thinning,breakage, reducing and the the cortical bone is thinning and porous, so that increased bone fragility,above established of the similar osteoporosis biomechanical model,though not exactly the same as osteoporosis physiological state,but from the perspective of the biomechanical analysis,the model in this study can be good simulation biomechanics study of animal osteoporosis models in vivo testing time. Use boiling method can fast,efficient,and controllable establish similar biomechanical model of osteoporosis state,to provide a reference for biomechanical study in a real state of osteoporosis.