寰枢椎椎弓根螺钉加横连杆加压治疗不稳定性Jefferson骨折的生物力学研究

目的：评价寰枢椎椎弓根螺钉＋横连杆加压治疗不稳定性Jefferson骨折的力学稳定性,为其临床应用提供力学依据。方法：6例完整枕骨颈椎湿润标本制成不稳定性Jefferson骨折模型,分别安装寰枢椎椎弓根螺钉系统和寰枢椎椎弓根螺钉加横连杆系统,通过摄像将1.53 Nm载荷下的三维运动记录脊柱三维运动稳定性评价方法,评价其重建寰枢椎即时稳定性的效果。结果：在屈伸和侧屈时,寰枢椎椎弓根螺钉＋横连杆固定组的运动范围小于寰枢椎椎弓根螺钉组,但差异没有统计学意义。在轴向旋转时,寰枢椎椎弓根螺钉加横连杆固定组的运动范围明显小于寰枢椎椎弓根螺钉组（P〈0.05）。结论：在失稳的寰枢椎节段上,寰枢椎椎弓根螺钉组及寰枢椎椎弓根螺钉加横连杆组固定后的三维运动明显减少,都能达到临床固定的目的。但是,寰枢椎椎弓根螺钉加横连杆组能够提供更强的抗旋转性能。

Biomechanical Study on Atlantoaxial Pedical Screw and Crosslink Compression for Instability Jefferson Fracture

Objective：In order to provide the mechanical evident of atlantoaxial pedical screw and crosslink compression for instable Jefferson fracture,we evaluated the stability of atlantoaxial junction fixation by it.Methods：six of the adult cervical spinal specimens which were entirewet-cadavers（from occipitale to C4） were made to simulate the unstable Jefferson fracture.These of specimens dislocated were fixed by atlantoaxial pedical screw and atlantoaxial pedical screw and crosslink system.The three dimensional movements of C1-C2 were recorded though photogrametry with a pure moment of 1.53 Nm.The range of motion（ROM） of each specimens in two fixations was caculated.Results：The ROM for the atlantoaxial pedical screw and crosslink lower than atlantoaxial pedical screw in flecion-extension and lateral bending（P0.05）.In axial torsion,the atlantoaxial pedical screw and crosslink significantly lower than atlantoaxial pedical screw（P0.05）.Conclusions：According to the biomechanical testing,atlantoaxial pedical screw and atlantoaxial pedical screw and crosslink system fixation on atlantoaxial instability provide excellent postoperative stability.However,atlantoaxial pedical screw and crosslink system fixation has better stability than atlantoaxial pedical screw in axial torsion.