寰椎一体式椎板钩与枢椎椎板钉组合应用于非对称内固定生物力学研究

Biomechanical evaluation of asymmetric atlantoaxial internal fixation system incorporated a combination of atlantal integrated hook and axial translaminar screw

目的本文报道设计一新型寰枢椎内固定组合,并在尸体标本进行生物力学试验,有一定的临床指导意义。方法将6具新鲜尸体颈椎标本置于2Nm载荷下,运用脊柱三维运动测量系统测量C1-2节段的三维运动范围(Range Of Motion,ROM),并将之进行两两对比。实验依完整组、失稳组、双侧寰椎侧块螺钉联合枢椎椎弓根螺钉内固定(Harms技术)组、寰椎侧块螺钉联合单侧枢椎椎板螺钉+对侧枢椎椎弓根螺钉固定组、一侧寰椎一体式椎板钩+枢椎椎板钉联合对侧寰椎侧块螺钉+枢椎椎弓根螺钉内固定组的顺序进行。结果失稳组ROM较完整组显著增加,内固定后ROM显著减小,三种内固定组中:寰椎侧块螺钉联合单侧枢椎椎板螺钉+对侧枢椎椎弓根螺钉固定组在旋转和侧屈方向上具有最小的ROM,双侧寰椎侧块螺钉联合枢椎椎弓根螺钉内固定组在屈伸运动方向上有最小的R0M。一侧寰椎一体式椎板钩+枢椎椎板钉联合对侧寰椎侧块螺钉+枢椎椎弓根螺钉内固定组ROM在旋转、侧屈以及屈伸方向上均较另外两组大,但差异均无统计学意义。结论寰椎一体式椎板钩与枢椎椎板钉组合非对称内固定可提供良好的生物力学稳定性。

Objective To design a neotype internal fixation combination for atlantoaxial poste- rior internal fixation,and to evaluate the biomeehanical performance of the combination. Methods 6 fresh human C0-C4 specimens were loaded with 2 Nm in the testing apparatus for the 3-D range of motion（ROM） of C1-2 with the help of the spinal motion testing system, as the following sequence：the intact group,the odontoid ectomy group,the Harms fixation group,the single C2 in- terlaminar screw group and a neotype combination group,which comprised of a lateral with C1 lateral mass and C2 pedicle screw and the other with C1 atlantal integrated hook and axial translaminar screw. And the ROMs were compared with each other. Results The ROM of each of the odontoid ectomy group increased significantly,and the ROM loading with 3 different inter- nal fixation showed remarkable decrease compared with the stable and destabilized model. The dada indicated that the single C2 interlaminar screw group presented smaller value of ROM thari the other two fixation groups in axial rotation and lateral bending. The Harms fixation group show better stability than the others in extention-flexion direction. While the neotype combination group presented more ROM than the others in axial rotation,lateral bending and extention-flexion direction,but there was no significant difference between all of these （P〉0.05）. Conclusion The neotype atlantoaxial internal fixation system has good biomechanieal performance.