椎弓根螺钉器械横杆作用的生物力学研究

目的　研究横杆对不同类型椎弓根螺钉器械稳定性的影响程度。方法　AF、Dick、VSP钢板三类椎弓根螺钉器械被安装在加载模型上 ,分别在 0、1、2个横杆状态下施加旋转扭矩 ,加载负荷为 2Nm、5Nm、8Nm ,记录不同负荷下的角位移 ,结果行成组设计资料t检验。结果　在 2Nm扭矩下 ,VSP与Dick组加用横杆角位移减少较小 (P >0 .0 5 ) ,AF组的角位移减少较多 (P <0 .0 5 )。在 5Nm、8Nm扭矩下 ,加用横杆后各型器械的稳定性明显增加 (P <0 .0 5 ) ,加用 2个横杆的角位移较 1个横杆的角位移明显减少 (P <0 .0 5 )。结论　横杆可以提高椎弓根螺钉器械的稳定性 ,加用 2个横杆效果优于加用 1个横杆 ;加用横杆可明显加强钉棒系统椎弓根螺钉器械的轴向稳定性

Biomechanical analysis of the cross-linkage of pedicle screw instrumentation

Objective To investigate the effect of the cross linkage to the stability of various type of spinal pedicle screw instrumentation.Methods AF instrumentation, Dick instrumentation and VSP plate instrumentation were fixed on the loading model. Rotation torque was loaded under 2?Nm,5?Nm,8?Nm when 0,1,2 cross linkages were used, respectively. According to the recorded angular displacement,a student test was performed.Results The reduction of angular displacement under 2?Nm torque are less in groups of VSP plate and Dick instrumentation when the cross linkage was used ( P >0.05). Furthermore, the stability of all instrumentations were increased significantly when the cross linkage was used under 5?Nm and 8?Nm ( P <0.05). The reduction of angular displacement in two cross linkage used were significantly less than in one cross linkage ( P <0.05).Conclusion Cross linkage can improve the stability of pedicle screw instrumentation. The effect of two cross linkage are superior to one cross linkage. In addition, this method can increase the axial stability of the rod and pedicle screw instrumentation significantly.