寰枢椎后路二种内固定技术的三维稳定性评价

Three-dimensional stability of two posterior internal fixation techniques on atlas and axis

目的:对比寰枢椎椎弓根螺钉固定系统与枢椎椎弓根螺钉联合寰椎椎板钩固定系统的生物力学稳定性,为临床应用提供实验依据。方法:新鲜颈椎标本6例,损伤齿突基底部,建立寰枢椎失稳模型,在脊柱三维运动实验机上先测量失稳寰枢椎的三维运动范围,再在失稳模型上对每具标本进行两种内固定:C1椎弓根螺钉+C2椎弓根螺钉的钉棒内固定系统,C1椎板钩+C2椎弓根螺钉的钉棒钩内固定系统,测量二种不同固定方法的寰枢椎三维运动范围,比较两种状态下的寰枢椎稳定状况。结果:C1椎弓根螺钉+C2椎弓根螺钉的钉棒内固定与C1椎板钩+C2椎弓根螺钉的前屈、后伸、左右侧屈无显著性差异,左右旋转C1椎弓根螺钉组优于C1椎板钩组。结论:两种寰枢固定方法:C1椎弓根螺钉+C2椎弓根螺钉固定系统在抗左右旋转方面较C1椎板钩+C2椎弓根螺钉固定系统的稳定性优越,临床上应优先选择C1、C2椎弓根螺钉固定方法,当C1椎弓根过于细小时可选用C1椎板钩+C2椎弓根螺钉的固定技术。

Objective： To evaluate three-dimensional stability of two different posterior internal fixation techniques on atlas and axis, and provide biomechanical basis for clinical application. Mothods： Six fresh specimens of cervical vertebra were fixed using different fixation methods： C1 plus C2 pedicle screws technique, and C1 laminar hook plus C2 pedicle screws fixation technique. After that, biomechanical data （range of motion, ROM） were measured and compared between two fixation methods. Resuilts： There was no statistical difference between two fixation methods for any motions. However, laminar hook-pedicle screws fixation significantly increased the ranges of rotation motion, as compared with pedicle screws fixations technique. Conclusiom： The biomechanical stability of C1 pedicle screws plus C2 pedicle screws technique is better than C1 laminar hook plus C2 pedicle screws fixation technique in aflatoaxial fixation. The first method is reliable to increase aflantoaxial instability.