脊柱失稳节段经椎弓根螺钉内固定器固定后对邻近节段三维运动的影响

The effcet of pedicle screw divice fixation on three dimensional movement of adjacent segments in thoracolumbar spine

目的 研究经椎弓根螺钉内固定器固定脊柱失稳节段后对邻近节段三维运动范围的影响。方法 在 7例新鲜成人尸体T1 0 ～L4 脊柱标本上 ,模拟L1 骨折后安放经椎弓根螺钉内固定器 ,在1 0 0N·m载荷下进行三维运动测试。分析脊柱固定阶段 (T1 2 ～L2 )、邻近节段 (T1 1 ～T1 2 、L2 ～L3)和总节段 (T1 1 ～L3)的前屈、后伸、轴向旋转和侧弯运动范围。结果 经椎弓根螺钉内固定器固定后能使固定节段屈伸、侧弯运动方向上运动范围减少 ,轴线旋转运动恢复至正常完整节段运动范围。但同时邻近节段屈伸、侧弯运动运动范围增加 ,轴向旋转运动范围无明显变化。固定后总节段比正常完整总节段屈伸、侧弯运动运动范围增加 ,轴向旋转运动范围无明显变化。结论 经椎弓根螺钉内固定器固定使邻近节段屈伸和侧弯运动范围代偿性增加 ,但不能代偿丢失的运动范围 。

Objective To study the changes of three dimensional movements of adjacent segments of the thoraco lumbar spine induced by pedicles screw device fixation Methods A model of L 1 body fracture was produced on seven specimens of fresh adult cadaver spine from T 10 to L 4.A pedicle screw device was applied in the spectimen to strengthen the injured level.Ranges of three dimensional movements of fixed segments (T 12 ～L 2),adjacent segment (T 11 ～T 12 ?L 2～L 3)and whole segments(T 11 ～L 3) were measured in intact,injured and the stabilized specimens.Results Although the pedicle screw device was found to provide significant stability for injured segment in flexion extension,lateral bending and restore stability to levels similar to those of an intact spine in axial rotation and at the same time the device increased the range of motion of the adjacent vertebral leval yet,there was a reduction of the range of motion of whole segment on flexion extension and lateral bending when compared with those of the intact spine.Conclusion Application of the pedicle screw device increase the range motion of flexion extension and lateral bending in adjacent segments which cannot compensate for the loss of those range of motion and have no influence on axial rotation.