带有辅助撑开拉杆的镍钛温度记忆合金椎体复位融合器的实验观察

目的 观察椎体复位融合器治疗创伤性和骨质疏松性椎体压缩骨折的生物力学性能.方法 用带有辅助撑开拉杆的镍钛温度记忆合金椎体复位融合器,在X线透视下经椎弓根入路植入实验性的尸体胸腰椎压缩骨折标本中,将塌陷的椎体终板复位并撑开压缩的椎体,采用X线和CT重建技术观察复位和撑开的效果,采用牛物力学测试机测量同定节段的疲劳强度.结果 本装置的温度形状记忆效应能基本达到复位塌陷的终板和椎体的撑开要求,超弹性特点又能使辅助撑开拉杆在复位和撑开效果不佳时给予额外的撑开复位力量.生物力学测试显示本装置能耐受超过1800 kg·m·s-2的纵向垂直负荷.结论 带有辅助撑开拉杆的镍钛温度记忆合金椎体复位融合器能达到有效的终板复位、椎体高度恢复和即刻脊柱生物力学稳定性,设计合理、适用于治疗创伤性和骨质疏松性椎体压缩骨折.

Utility of nickel-titanium shape memory alloys of vertebral body reduction fixator with assisted distraction bar

Objective To test the nickel-titanium (Ni-Ti) shape memory alloys of vertebral body reduction fixator with assisted distraction bar for the treatment of traumatic and osteoporotic vertebral body fracture. Methods A Ni-Ti shape memory alloys of vertebral body reduction fixator with assisted distraction bar was implanted into the compressed fracture specimens through vertebral pedicle with the radiographic monitoring to reduce the collapsed endplate as well as distract the compressed vertebral fracture. Radiographic film and computed tomographic reconstruction technique were employed to evaluate the effects of reduction and distraction. A biomechanic test machine was used to measure the fatigue and the stability of deformation of fixation segments. Results Relying on the effect of temperature shape memory,such an assembly could basically reduce the collapsed endplate as well as distract the compressed vertebral fracture. And when unsatisfied results of reduction and distraction occurred, its superflexibility could provide additional distraction strength. Conclusion A Ni-Ti shape memory alloys of vertebral body reduction fixator with assisted distraction bar may provide effective endplate reduction, restore the vertebral height and the immediate biomechanic spinal stability. So the above assembly is indicated for the treatment of traumatic and osteoporotic vertebral body fracture.