脊柱改良横突钩棒系统的生物力学研究

Biomechanical tests on an improved transverse process hook and rod system for correction of scoliosis

[目的]验证横突钩棒系统的有效性,为其临床应用提供理论基础。[方法]收集5具新鲜冰冻尸体腰椎标本(L1~L5),每个标本分别进行三种状态,也就是自然状态(完整组)、横突钩棒固定状态(钩棒组)、椎弓钉棒固定状态(钉棒组),通过脊柱三维运动系统施加8 N·m力矩使标本产生6个方向的运动,包括前屈、后伸(矢状面)、左右侧弯(冠状面)、左右轴向旋转(水平而),记录活动度(ROM)。[结果] L2/3和L3/4的前屈、后伸、侧弯和旋转各向ROM,完整组最大,钩棒组次之,钉棒组最小。在矢状面ROM,钩棒组与完整组的差异无统计学意义(P>0.05),而钉棒组的ROM显著少于前两组(P<0.05)。左右侧弯ROM,钩棒组与钉棒组明显小于完整组,差异有统计学意义(P<0.05),而钩棒组与钉棒组间差异无统计学意义(P>0.05)。左右轴向旋转ROM,钩棒组与钉棒组明显小于完整组,差异有统计学意义(P<0.05),而钩棒组与钉棒组间差异无统计学意义(P>0.05)。[结论]相比于椎弓根钉棒系统,改良的横突钩棒系统能提供脊柱在冠状面和水平面上类似的稳定性,但保留矢状面部分活动。

[Objectives] To verify the effectiveness of the improved transverse process hook and rod system and provide a theoretical basis for its clinical application in correction of scoliosis.[Methods] Five fresh frozen human cadaveric lumbar spine specimens(L1~L5) were used in this study. Each specimen was tested successively in 3 conditions, including intact state(the intact group), condition fixed with transverse process hook and rod system(the hook-rod group), as well as condition fixed with pedicle screw and rod system(the screw-rod group). Under load of 8 N×m applied, the ranges of motion(ROM) in 6 freedoms,including flexion-extension(the sagittal plane), right-left bending(the coronary plane), and right-left rotation(the transverse plane) were recorded by a spinal three dimensional motion testing machine.[Results] All the 6-freedom ROMs, such as flexion, extension, right bending, left bending, right rotation and left rotation, were ranked from maximum to minimum in sequence as the intact group, the hook-rod group and the screw-rod group. In term of motions at the sagittal plane, the hook-rod group was not statistically significantly different to the intact group(P>0.05), although both of them had significantly greater ROMs than the screw-rod group(P<0.05). In term of motion at the coronal plane, the intact group had significantly higher ROM of right and left bending than the hook-rod group and the screw-rod group(P<0.05), despite of the fact that no statistically significant differences between the hook-rod and screw-rod groups(P>0.05). In addition, the hook-rod group was not statistically significant different with the screw-rod group regarding to the right and left rotations, although both of them had significantly less ROMs than the intact group(P<0.05).[Conclusions] Compared with the pedicle screw and rod system, the improved transverse process hook and rod system provides similar stability in the coronal and horizontal planes, and preserves motion in some extent in the sagittal plane.