枢椎交叉椎板螺钉新技术治疗寰枢椎不稳的生物力学比较

目的对枢椎交叉椎板螺钉治疗寰枢椎不稳这一新的内固定技术进行生物力学评估。方法成年国人甲醛固定的枕颈（C0～C4）标本10具，对寰枢椎不稳模型分别行Gallie法内固定、双侧Magerl法内固定、C1椎弓根-C2交叉椎板螺钉内固定，进行寰枢关节的强度、刚度测量，分析寰枢椎的载荷-位移、应力-应变、扭矩-扭角关系和扭转刚度指标。结果Gallie法内固定明显增强了寰枢椎不稳模型的稳定性，但其固定强度明显小于Magerl法和C1椎弓根-C2交叉椎板螺钉内固定（P〈0．05），C1椎弓根-C2交叉椎板螺钉内固定强度大于双侧Magerl法，但没有统计学意义（P〉0．05）。结论C1椎弓根-C2交叉椎板螺钉内固定能为失稳的寰枢关节提供坚强的生物力学环境，枢椎交叉椎板螺钉技术具有良好的临床应用前景。

Biomechanical comparison of a novel technique with C2 crossing laminar screws in posterior atlantoaxial fixation

Objective To evaluate the biomechanical stability afforded across the atlantoaxial segment by a new technique using C_2 crossing laminar screws.Methods Ten embalmed cadaver human cervical spine specimens(C_0-C_4) were collected.The biomechanical strength and rigidity of three posterior fixation procedures-Gallie method,posterior C_(1-2) transarticular screw(Magerl technique),C_1 pedicle screw/C_2 crossing laminar screws-rod construct were compared.Results The Gallie method improved the stability of atlantoaxial instability model significantly,but had the lowest stiffenss among the three types of fixation.The C_1 pedicle screw/C_2 crossing laminar screws-rod construct seemed to have higher stiffenss than Magerl technique,but the difference was statistically insignificant(P>0.05).Conclusions C_1 pedicle screw/C_2 crossing laminar screws-rod construct can provde satisfactory biomechanical stiffness for atlantoaxial instability.C_2 crossing laminar screws technique is a promising technique in clinical application.