脊柱胸腰段骨折后路经伤椎单节段固定与常规短节段固定的力学性能比较  

Biomechanical comparison of monosegmental and short transpedicular fixation for stabilization of thoracolumbar fractures

作　　者：徐桂军[1,2] 马信龙[1,2] 张弢[2] 马剑雄[2] 付鑫[1] 杜长岭[2] 

机构地区：[1]天津医院骨研所生物力学室,天津300211 [2]天津医科大学总医院骨科,天津300052

出　　处：《医用生物力学》2014年第2期126-130,共5页Journal of Medical Biomechanics

基　　金：国家自然科学基金资助项目(11072021);吴阶平医学基金会临床科研专项资助基金(320.6750.11017)

摘　　要：目的 应用三维有限元技术构建胸腰椎骨折经伤椎单节段固定及常规短节段固定模型，研究经伤椎单节段固定的生物力学特点，论证其在胸腰椎骨折治疗中应用的可行性。方法 选取青壮年健康男性志愿者，利用CT扫描数据建立脊柱T10~L2正常模型、T12骨折模型以及经伤椎单节段固定和短节段固定模型；分析在轴向压缩、前屈、后伸、侧屈及轴向旋转下各个节段的最大位移差及内固定物的应力情况。结果 骨折模型T10~11、T11~12、T12~L1的最大位移差较正常模型在大多数加载情况时明显增大，经短节段或者经伤椎单节段固定后，该值明显减小，两种固定方式无显著差异。内固定物应力方面：在轴向压缩及前屈时，经伤椎单节段固定模型中螺钉应力明显低于短节段固定；而在后伸、侧屈及轴向旋转时，螺钉应力无明显差异。对于固定棒，轴向压缩及前屈时，两种固定方式无差异；后伸及侧屈时经伤椎节段固定应力高于短节段固定，而旋转时则恰恰相反。结论 对于胸腰段单节段不完全骨折，经伤椎单节段固定可以提供与常规短节段固定相近的生物力学稳定性，是治疗胸腰椎不完全骨折的一种良好的选择。Objective To establish the monosegmental transpedicular fixation model and short segmental fixation model by three-dimensional finite element technique, and evaluate the biomechanical properties of monosegmental transpedicular fixation for thoracolumbar fractures and verify its feasibility for application. Methods T10-L2 motion segment of a young healthy subject was used to establish the normal finite element model. The superior 1/2 cortical bone of the T12 segment was removed and superior 1/2 cancellous bone of the same vertebrae was assigned material property of the injured bone to simulate the thoracolumbar fracture. Transpedicular screw fixation of the T11 and T12 segment was performed in monosegmental fixation model. T11 and L1 segment were instrumented in the short segmental fixation model. All the four finite element models were applied with loading of axial compression, anteflexion, extension, lateroflexion and axial rotation, respectively. Motion difference of each functional unit and the stress of implants were measured to evaluate biomechanical behaviors of monosegmental fixation. Results The motion difference of all the functional units （T10-11, T11-12, T12-L1） in the fractured model was obviously increased under all loading conditions as compared to the normal model, but the motion difference in the fractured models was decreased after monosegmental fixation and short segmental fixation, and no significant differences were found between monosegmental fixation and short segmental fixation. The stress on screws in monosegmental fixation model was significantly lower than that in short segmental fixation under axial compression and anteflexion, but the stress on screws of two fixation models had no significant difference under extension, lateroflexion and axial rotation. The stress on the rods of monosegmental fixation model was apparently higher than that of short segmental fixation under extension and lateroflexion, and lower under axial rotation, but no significant difference was found for two fi

关 键 词：胸腰椎骨折 单节段固定 力学特性 有限元分析 

分 类 号：R318.01[医药卫生—生物医学工程]