CBT螺钉治疗A3型胸腰段骨质疏松性骨折的生物力学研究

Biomechanical Study of Cortical Bone Trajectory Screw Fixation in the Osteoportic Type-A3 Thoracolumbar Fractures

目的观察皮质骨通道螺钉固定A3型胸腰椎骨质疏松性椎体骨折的生物力学即刻稳定性。方法取6具新鲜老年尸体胸腰段脊柱标本,在MTS-858脊柱生物力学实验机上测试原始状态、传统固定、皮质骨通道螺钉(cortical bone trajectory,CBT)固定、骨折传统固定、骨折CBT固定五种工况下的L1～3的活动范围。结果传统固定组、CBT固定组的三维六自由度活动范围较原始状态组明显降低(P<0.01),传统固定组和CBT固定组之间没有显著差异。骨折传统固定组和骨折CBT固定组的三维活动总体上比原始状态组降低(P<0.05),但是骨折传统固定组和骨折CBT固定组之间差异无统计学意义。骨折传统固定组和骨折CBT固定组的三维活动,分别比传统固定组和CBT固定组之间的三维活动有所增加,但是差异无统计学意义(P>0.05)。结论骨折后CBT螺钉固定可获得与骨折后普通椎弓根螺钉固定相似的即刻稳定性,CBT螺钉固定可用于老年A3型骨质疏松性胸腰椎骨折的临床治疗。

Objective To analyze biomechanical stability of cortical bone trajectory system inthe osteoporotic type-A3 thoracolumbar fractures.Methods Six fresh thoracolumbar spinal function units(L1~3)were harvested from old cadaver spines.Bone mineral density(BMD)was measured for all the vertebral bodies.The ranges of motion of all specimens were detected on the MTS-858 spinal biomechanics testing instrument under different states respectively,normal state,classic pedicle screw fixation,cortical bone trajectoryscrew fixation,type A3 L2 vertebral body fracture classicpedicle screw fixation,and type A3 L2 vertebral body fracture cortical bone trajectory screw fixation.Results Ranges of motion at flexion,extension,left bending,right bending,left axial rotation and right axial rotation were significantly lower in the cortical bone trajectory screw group and classic pedicle screw group than in the normal state group(P<0.01).There were no significant differences between the rages of motion of the cortical bone trajectory screw fixation group and classic pedicle screw fixation group.The ranges of three-dimensional motion were significantly lower in the type A3 L2 vertebral body fracture classic pedicle screw fixation group and type A3 L2 vertebral body fracture cortical bone trajectory screw fixation group than in the normal state group(P<0.05).Likewise,there were no significant differences between the range of motion of the type A3 L2 vertebral body fracture classic pedicle screw fixation group and type A3 L2 vertebral body fracture cortical bone trajectory screw fixation group(P>0.05).The range of motion between the classic pedicle screw fixation group and the type A3 L2 vertebral body fracture classic pedicle screw fixation group was insignificant(P>0.05).Conclusion These results confirmed that cortical bone trajectory technology can obtain similarimmediatestability as the traditional pedicle screw fixationinthe osteoporotic type-A3 thoracolumbar fractures.Simultaneously,it is a good choice for the osteoporotic type-A3 thoracolumbar fractures.