枢椎侧块关节前倾对寰枢椎稳定性的影响及不同重建方式的生物力学评价

The influence of anteversion of the C2 lateral mass joint on the stability of atlantoaxial joint and biomechanical evaluation of different reconstruction methods

目的 :探讨枢椎侧块关节前倾对寰枢椎稳定性的影响及不同重建方式的生物力学稳定性,为指导临床术式选择提供理论依据。方法:选取6具男性新鲜尸体枕颈部标本(枕骨髁基底C0~C3),年龄18~50岁,每具标本依次制作成完整状态模型(A组)、切断标本齿状突基底部造成齿状突Ⅱ型骨折制作寰枢椎不稳模型(B组)、枢椎侧块25°前倾楔形截骨模型(C组)、后路寰枢椎椎弓根钉棒内固定模型(D组)及后路寰枢椎椎弓根钉棒内固定+侧块关节间植骨模型(E组),在脊柱三维运动试验机上分别给予1.5N·m的屈/伸、左/右侧弯、左/右旋转力矩,测量不同模型的三维运动范围(ROM)。结果:A组在屈/伸、左/右侧弯和左/右旋转运动的ROM分别为10.80°±0.74°/10.90°±0.54°、9.18°±0.97°/9.06°±0.47°、23.07°±0.27°/23.15°±0.63°;B组分别为15.88°±0.56°/16.20°±0.48°、17.12°±0.35°/17.27°±0.51°、34.15°±0.38°/34.27°±0.44°;C组分别为18.93°±0.61°/20.16°±0.54°、26.18°±1.34°/25.26°±0.71°、40.86°±0.60°/41.16°±0.38°;D组分别为0.64°±0.19°/0.57°±0.11°、2.01°±0.45°/1.86°±0.34°、1.36°±0.18°/1.76°±0.13°;E组分别为0.63°±0.15°/0.51°±0.17°、1.28°±0.86°/1.42°±0.22°、0.50°±0.28°/0.59°±0.26°。在屈/伸、左/右侧弯运动中,C组的ROM最大,与其他组两两比较差异有显著性(P<0.05),B组和C组的ROM均较A组明显增大(P<0.05),D组和E组的ROM均较A组、B组、C组明显减小(P<0.05),D组和E组比较无统计学差异(P>0.05);在左/右旋转运动中,C组的ROM最大,E组的ROM最小,D组和E组的ROM均较A组、B组、C组明显减小(P<0.05),D组和E组比较差异有显著性(P<0.05)。结论:枢椎侧块关节前倾角度增大会明显增加寰枢椎的ROM,导致其在屈/伸、侧弯及抗旋转的稳定性明显下降,后路寰枢椎椎弓根钉棒内固定在屈/伸、左/右侧弯运动的稳定性与后路寰枢椎椎弓根钉棒内固定+侧块关节间植骨相似,但在限制寰枢椎旋转运动的能力较弱。

Objectives:To provide a new theoretical basis by elucidating the influence of the anteversion of the C2 Lateral mass joint on the stability of the atlantoaxial joint and the biomechanical stability of different reconstruction methods.Methods:Six male fresh human cadaveric neck specimens(C0-C3 of the occipital epiphysis)were selected.Each specimen was made into a complete state model(group A),atlantoaxial insta-bility model by cutting the odontoid base of the specimen and causing a odontoid typeⅡfracture(group B),25°forward tilt wedge osteotomy model(group C),posterior atlantoaxial pedicle screw fixation model(group D),and posterior atlantoaxial pedicle screw fixation and lateral block joint bone grafting model(group E).1.5 N·m torque was added at flexion/extension,left/right bending and left-handed/right-handed on the spine three-dimensional motion test machine to measure the three-dimensional range of motion(ROM)under different models.Results:The ROM of the flexion/extension,left/right bending and left-handed/right-handed motion of group A were:10.80°±0.74°/10.90°±0.54°,9.18°±0.97°/9.06°±0.47°,23.07°±0.27°/23.15°±0.63°;that of groupB were 15.88°±0.56°/16.20°±0.48°,17.12°±0.35°/17.27°±0.51°,34.15°±0.38°/34.27°±0.44°;of group C were18.93°±0.61°/20.16°±0.54°,26.18°±1.34°/25.26°±0.71°,40.86°±0.60°/41.16°±0.38°;of group D were 0.64°±0.19°/0.57°±0.11°,2.01°±0.45°/1.86°±0.34°,1.36°±0.18°/1.76°±0.13°;of group E were 0.63°±0.15°/0.51°±0.17°,1.28°±0.86°/1.42°±0.22°,0.50°±0.28°/0.59°±0.26°.In flexion/extension and left/right bending,the ROM of the group C was the largest,and the differences between group C and any other group were significant(P<0.05).The ROM of group B and group C were significantly higher than that of group A(P<0.05).Compared with group A,group B and group C,the ROM of group D and group E were both significantly smaller(P<0.05),there was no significant difference between group D and group E(P>0.05).In left-handed/right-handed,group C had the largest ROM and group E the smallest.The ROM of group D and group E were significantly lower than that of group A,group B and group C(P<0.05).The difference between group D and group E was significant(P<0.05).Conclusions:The increase of the anterior tilt angle of the C2 lateral mass joint can significantly increase the ROM of the atlantoaxial vertebra,resulting in a significant decrease in the stability of flexion/extension,lateral flexion and anti-rotation.In posterior atlantoaxial pedicle screw fixation,the stability of the flexion/extension and left/right bending motions is similar to that of the posterior atlantoaxial pedicle screw fixation and lateral block joints,but the ability to restrict the atlantoaxial rotational motion is weak.