| ObjectiveApply the extracorporal quintuplet osteoporosis vertebral model come from adult porcine thoracolumbar spine that intermediate vertebral was compressed fracture,statist-ical and analysis the strength and rigidity of spinal unit before modeling and the strength and rigidity and new fracture of vertebral body,bone cement leakage after modelled and applied percutaneous kyphoplasty.To study the effect of bone cement dosage on the biomechanics of the extracorporal quintuplet osteoporosis vertebral model after PKP.MethodsSelect a common carnivorous pig,average body weight of 105 kg,the average body length of 1.3 m,the average height of 60cm,after the slaughter of the spine out,choose T12~L2 section of five vertebral bodies were combined for a spinal unit,that was called quintuplet vertebral spine unit.Observation by naked eye,DR,avoid vertebral model dysplasia,malformations and other defects exist.Bone mineral density.BMD)values were measured and recorded,and the models with different BMD values were removed.A total of 60 in line with the requirements of the experimental model of vertebrae,were randomly divided into A,B,C,D4 group,every group has 15 quintuplet vertebral spine unit model.All through the middle vertebral drilling decalcification model making into the middle vertebral osteoporosis model with electronic mechanical testing machine axial stress load applied to each unit of production into the middle of spinal osteoporotic vertebral compr-ession fracture model and II degrees,get the ultimate compressive strength S and rigidity R of each spinal unit.By soaking decalcified 4 groups of spinal unit made into the model of osteoporosis.After the modeling,measuring and recording each spinal unit after decalcification BMD value.A group as a blank control group,no PKP operation;B,C,D group underwent unilateral(right)puncture approach PKP,the amount of bone cement was15%,25%,35%of the volume of the injured vertebrae,and the leakage of bone cement was recorded.After the completion of 24h,all the spine units were placed on the electronic mechanical testing machine and the axial load was applied.Record the ultimate compre-ssive strength S'and rigidity R'of each spinal unit.B,C,and D groups continued to press until second new fractures of the vertebral body were recorded,and the location of the new fracture was recorded.ResultsBone density of 60 normal spinal units:The average was 1.058±0.013 g/cm~2 before decalcified,the average was 0.613±0.044 g/cm~2 after decalcified,descent rate was more than 40 percent.To prove the establishment of the extracorporal quintuplet osteoporosis vertebral model come from adult porcine thoracolumbar spine that intermediate vertebral was compressed fracture.The rigidity of B,C and D group after spinal unit was been strengthened was 234±8 N/mm,259±12 N/mm and 294±13 N/mm,all were better than the A group 204±12 N/mm that not been strengthened.The difference was statistically significant(P<0.05).The ultimate compressive strength of B,C and D group after spinal unit was been strengthened was 3428±96N,3134±86 N and 2615±90 N,all were better than the A group 1758±55N that not been strengthened.The difference was statistically significant(P<0.05).B,C,D group were 17,21,and 27 new vertebral fractures located in the adjacent position of the strengthening vertebral.The difference was statistically significant(P<0.05).B,C,D group were 1,3,and 11 spinal units of bone cement leakage.The difference was statistically significant(P<0.05).ConclusionPKP can effectively restore the mechanical properties of fractured vertebral body,and Its rigidity and ultimate compressive strength are improved obviously.It can avoid further collapse and deformation of fractured vertebrae.However,the stress of the adjacent vertebral body was increased significantly after the injection of bone cement,and increased with the increase of the amount of bone cement injection.The amount of bone cement is one of the factors leading to vertebral fractures... |
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