用于治疗难复位性寰枢椎脱位的新型经口前路寰枢椎侧块融合器的生物力学研究

Biomechanical study of a novel transoral atlantoaxial lateral mass fusion cage used for irreducible atlantoaxial dislocation

目的比较新型寰枢椎侧块融合器与传统内固定方式(TARP+髂骨块内固定技术,后路椎弓根钉棒固定技术)的生物力学差异。方法收集40例TARP术后病人的CT扫描数据进行测量并设计新型融合器。挑选6具新鲜上颈椎标本。分别进行完整状态,失稳状态及进行3种内固定方式[(TARP+融合器(A1);TARP+髂骨块(A2);后路椎弓根钉棒技术(B)]处理。再测量不同状态下标本的屈伸,侧屈,旋转6组动作的活动范围(ROM)并进行统计学分析。结果新型融合器有三种型号:13/12/7,12/11/7,11/10/7(长/宽/高);矢状面角设计为:16°/18°/20°。生物力学数据分析显示:Cage组(A1)与髂骨组(A2)在6个方向的活动度差异无统计学差异(P>0.05);在屈伸及旋转活动中,TARP固定组(A1、A2)与后路固定组(B)不存在显著差异(P>0.05);在侧屈活动中,TARP固定组(A1、A2)与后路固定组(B)存在显著差异(P<0.05)。结论配合TARP技术使用的新型融合器与TARP+髂骨块的生物力学稳定性相仿,在侧屈方向优于寰枢椎后路椎弓根螺钉技术。且融合器相对于髂骨块而言,理论上具有以下优势:(1)简化手术步骤;(2)避免取髂骨相关并发症。

Objective To compare the stabilities of the lateral mass fusion cage and iliac crest autograft combined with Transoral Atlantoaxial Reduction Plate （TARP） system and posterior C1-C2 pedicle screw-rod system. Method Cage was designed based on the three-dimension parameters of 40 postoperative patients operated with TARP. Range of motion （ROM） in flexion-extension, left-right bending and axial rotation of 6 cadaveric specimens with different treatments were recorded. Results The measured data indicated that feasible cage design were in 3 sizes：13/12/7/16°,12/11/7/18°,11/10/7/20°（length/width/height/sagittal angle）;ROM of TARP （combined with Cage or ilium） was smaller compared with posterior C1-C2 pedicle screw-rod system and difference between left and right bending was statistically significant. Conclusion The stiffness was analogous between TARP system （combined with cage or iliac crest autograft） and posterior C1-C2 pedicle screw-rod system. Furthermore, cage combined with TARP may simplify surgeric procedure and decrease the incidence of clinical complication.