A Study Of Bone Formation And Biochemical Properties In The Treatment Of Thoracolumbar Vertebrae Fractures Using Calcium Sulfate Cement

1.Bone formation of injectable calcium sulfate in rabbit spongy boneObjective: investigate biodegradation and bone formation of injectable calcium sulfate in rabbit spongy bone.Method: Eighteen rabbits were randomly signed to 2 groups, A and B. Osseous defeats were created in lumbar bodies using a drill, resulting in a 3.2mm diameter *5mm deep cavity. The prepared material(CSC) was injected into cavities in group A, group B was untreated as blank control, their general and local reactions in implanted regions were observed. The bone formation and degradation were observed in 2,6 and 12 weeks by macroscopically, microscopically, x-rays and tissue slices. Photographs were selected in each group at each time points for computer software processing to calculate the percentages of bone in the images of postoperative slices.Results: All rabbits were recovered within 1 day following the procedure, wounds healed in a routine manner, and there were no inflammatory response. Photographs at 2,6,12 weeks demonstrated progressive, resorption of CSC and replacement by bone. At 12 week, the stained show has completely resorbed, thickened; interconnected trabeculae and newly wove bone were seen. The bone percentage in group A was significantly higher than in group B (p<0.05).Conclusion: CSC is more compatible, it can induce early new bone formation and the rate of resorption equals the rate of new bone formation. It is a good bone graft substitute material.2.Biomechanical properties of injectable calcium sulfate cement in cadaveric osteoporotic vertebral fracture.Objective : To evaluate the biomechanical performance of CSC for vertebroplasty in cadaveric osteoporotic vertebral bodies. Method : 25 vertebral bodies from 5 osteoporotic cadaveric spines were signed to 3 groups: Group A―no cement; Group B―PMMA; Group C―CSC. Each vertebral body was stripped of soft tissue and the posterior elements removed, and the bone mineral density (BMD), initial height of each body were measured. Each vertebral body was compressed on a material testing machine to create an anterior wedge fracture and reduce the anterior height by 25%. Pretreatment strength and stiffness were measured. Drilling a hole and then PMMA was injected in group B; CSC was injected in group C. All vertebral bodies were recompressed by 25% of anterior height to obtain posttreatment strength, stiffness and height.Results : There were no significant differences in BMD, initial strength and initial stiffness of vertebrae between the 3 groups. After cement augmentation, the height and strength of the augmented vertebrae was significantly greater than blank control (p<0.05). Group C is closer to initial strength. The stiffness of the augmented vertebrae was significantly greater then that of the blank control, but it was not restored to the initial level.Conclusion: CSC as a new bone graft substitute material can restore the height and strength of vertebral body, it can restore initial stabilization.