胸腰椎骨折伤椎椎弓根内固定的生物力学研究

目的:通过生物力学测试对胸腰椎骨折伤椎椎弓根内固定进行评价。方法:取5具新鲜小牛的胸腰椎脊柱标本(T12-L6),制作成严重前中柱损伤模型,应用椎弓根螺钉内固定,测试标本应用不同固定方法后在轴向压缩,屈伸和扭转试验中生物力学稳定性及长短椎弓根螺钉的握持能力,探讨伤椎固定对脊柱稳定性的影响。结果:3种螺钉固定(包括:8钉固定、6钉固定、4钉固定)方式,均能提高骨折失稳脊柱的各向稳定性。而6钉固定(伤椎固定)与8钉固定对失稳脊柱的各向稳定性的加强程度较为接近(P>0.05),且均高于4钉固定形式(P<0.05)。结论:生物力学测试证明,胸腰椎骨折伤椎椎弓根内固定能加强脊柱的稳定性。

A Biomechanial Study of Transpedicular Fixation into the Injured Vertebra for Thoracolumbar Fractures

Objective:To evaluate biomechanism on the pedical screws fixed into the injured vertebra for thoracolumbar fractures.Method:5 fresh calf thoracolumbar spinal fracture(T12-L6) were made to compare the stability of three kind of ways for transpedicular fixation by its axial compression,bending,rotation and axial extraction force of the long and short pedical screw.To explore the stability of spine in fracture thoracolumbar vertebra fixed with pedical screws.Results:All of the three kind ways for transpedical fixation(fixed with 4,6 or 8 pedical screws) can restore the stability of injured thoracolumbar vertebra in axial compression,bending,rotation.No statistical difference of spine stability capacity was found between 6 pedical screws fixation and 8 pedical screws fixation(P>0.05),but both of them had statistical difference of spine stability capacity compared with 4 pedical screws fixation(P<0.05).Conclusion:Biomechanial study proved that transpedicalar fixation into the injured vertebra can enhance the stability of spine.