两种齿状突切除术对颅颈交界区稳定性影响的有限元分析

Finite element analysis of the effect of two kinds of odontoidectomy on the stability of cervical junction

目的通过构建上颈椎有限元模型研究两种齿状突切除术对颅颈交界区(craniocervical junction,CCJ)稳定性影响的生物力学差异。方法采用有限元软件构建Oc-C2的正常上颈椎实体模型,然后在正常模型的基础上构建常规齿状突切除模型及保留C1前弓的微创齿状突切除模型,进而在有限元软件ABAQUS v6.9.1.中分析各种模型的生物力学差异,从而得出齿状突切除术中保留C1前弓的生物力学优势。结果常规齿状突切除术对C1-C2的活动度影响较Oc-C1显著,各向活动度增加分别为前屈23%、后伸97%、侧弯231%、轴向旋转349%;对Oc-C1的稳定性同样有明显影响,其中Oc-C1后伸活动度影响最大,增加达196%。保留C1前弓的齿状突切除术可明显缩减C1-C2轴向旋转活动度的增加,实验中仅出现轻度代偿性的活动度减少;而其他方向活动度仍有异常的增加(Oc-C1后伸活动度增加167%、C1-C2侧弯活动度增加181%)。结论齿状突切除术对C1-C2的活动度影响显著,但对Oc-C1的活动度同样有明显影响。保留C1前弓的齿状突切除术可保护脊柱轴向旋转的活动度,但仍存在脊柱不稳定因素。

Objective To study the biomechanical impact of two different kinds of odontoideetomy on the stability of cervical junction through a validated finite element model of Oc - C2. Methods A validated finite element model of Oc - C2 was constructed to study the biomeehanical changes due to the surgery of traditional odontoideetomy and odontoidectomy with anterior C1 arch preservation. These models were analyzed in ABAQUS v6.9.1, to study the biomechanical impact of anterior C1 arch preservation. Results Odontoidectomy produced more motion increase at C1 - C2 than Oc - CI. At C1 - C2, the pereentages of motion increase were 23% , 97% , 231% and 349% in flexion, extension, lateral bending and rotation. However, the motion increase at Oc -C1 was also significant, especially in extension with 196% increase than normal model. Odontoidectomy with preservation of anterior C1 arch preserved the motion of axial rotation at CI - C2, but the deviant increase also could be seen in extension at Oc - C1 （ 167% ） and bending at C1 - C2 （ 181% ）. Conclusions Odontoidectomy can produce more motion increase at C1 - C2 than Oe - C1 ,but also produce significant motion increase at Oc - C1. Odontoidectomy with preservation of anterior C1 arch can preserve the axial rotation motion at C1 - C2, but the abnormal increase can also be seen in other segmental motions.