寰椎椎板钩联合枢椎椎弓根螺钉内固定的力学稳定性评价

第一作者：李松凯

2011-06-01 点击量：1100 　　我要说

李松凯，倪斌，王明飞，张锋，郭翔，王健，赵卫东

摘要：目的评价寰椎椎板钩联合枢椎椎弓根螺钉内固定的生物力学稳定性.方法取6具新鲜尸体颈椎标本置于1.5 N·m载荷下,测量C_(1-2)节段的三维运动范围(ROM).标本按随机顺序,依次行完整状态(完整状态组)、不稳状态(齿状突周围韧带切除,为不稳状态组)、经寰枢关节间隙螺钉联合Gallic内固定(固定A组)、寰椎椎板钩联合枢椎椎弓根螺钉内固定(固定B组)、寰枢椎椎弓根螺钉内固定(固定C组)5种状态下的三维ROM值测量.比较各组标本的屈伸、侧屈、旋转ROM值.结果完整状态组、不稳状态组、固定A、B、C组的平均屈伸ROM值分别为17.78°、30.69°、2.25°、2.93°、2.73°,组间比较差异有统计学意义(F=216.69,P=0.000);平均侧屈ROM值分别为9.56°、17.18°、1.91°、2.30°、2.05°,组间比较差异有统计学意义(F=122.75,P=0.000);平均旋转ROM值分别为44.19°、57.30°、1.22°、2.88°、2.07°,组间比较差异有统计学意义(F=154.54,P=0.000).固定A、B、C组较完整状态组和不稳状态组各个方向的ROM值均明显减少,差异均有统计学意义(P<0.05),但固定A、B、C组之间符个方向的ROM值比较差异均无统计学意义(P>0.05).结论寰椎椎板钩联合枢椎椎弓根螺钉内固定可提供与经寰枢关节间隙螺钉联合Gallic内固定和寰枢椎椎弓根螺钉内固定相当的力学稳定性.在以上两种方法无法实施时,可作为一种安全的替代.

Abstract：Objective To compare the biomechanical stabilities of fixation with bilateral C1 hooks plus C2 pedicle screws, fixation with C1-C2 transarticular screws plus Gallic wires and fixation with C1-C2 pedicle screws. Methods Six specimens of cervical spines (C0-C4) taken from 6 fresh-frozen human their intact condition, destabilization by disrupting the transverse-Mar-apical ligament, fixation with transar-ticular screws plus Gallic posterior wires, fixation with C1 hooks plus C2 pedicle screws, and fixation with C1-C2 pedicle screws.Pure moment loading, up to 1.5 N·m, was applied to the occiput in flexion-extension, right-left lateral bending, and right-left axial rotation to determine the relative intervertebral rotations using a camera system. The ranges of motion (ROM) for the intact, destabilized and 3 fixation sce-narios were determined. Statistical analyses were performed using one-way analysis of variance, with Fishers least significant difference post hoc test for multiple comparisons. Results The data indicated that the C1-C2 motion significantly increased for all rotations in the cases of disrupted ligament. The motion in all the 3 fixations significantly reduced compared with the intact and destabilized cases (P<0.05). The transar-ticular screws and Gallic fixation allowed the smallest ROM in all directions tested except in flexion/ex-tension in the 3 fixation groups while the C1 hooks plus C2 pedicle screws fixation produced the largest ROM. No significant difference was found in the acute stability among the 3 fixations tested(P>0.05). Conclusions The C1 hooks plus C2 pedicle screws fixation appears as effective as the fixations with transartieular screw-wiring construct and C1-C2 pedicle screws in reducing the relative atlantoaxial motion in a severely destabilized upper cervical spine. In cases where the latter two methods are not feasible, fixation with C1 hooks plus C2 pedicle screws may be a safe alternative for treatment of atlantoaxial stabilization.

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