脊柱骨折经伤椎椎弓根置钉附加横连短节段固定的稳定性测试

Biomechanical study of transpedicular fixation via injured vertebra plus connector for short-segment instrumentation of the spinal fracture

中文关键词:  脊柱骨折  椎弓根螺钉  经伤椎固定  稳定性

英文关键词:Spinal fracture  Pedicular screw  Fixation of the fractured vertebra  Stability

中文摘要:

  【摘要】 目的：探讨脊柱骨折经伤椎椎弓根置钉附加横连短节段钉棒固定的稳定性。方法：5具新鲜冰冻小牛腰椎标本（L1~L5）制备成L3椎体爆裂骨折模型，依次进行单纯经伤椎和上下相邻椎体椎弓根置钉短节段6钉固定（单纯经伤椎6钉固定组）和附加横连经伤椎和上下相邻椎体椎弓根置钉短节段6钉固定（附加横连经伤椎6钉固定组），测试L2~L4损伤前（对照组）、损伤后（骨折组）及单纯经伤椎6钉固定组和附加横连经伤椎6钉固定组的三维6个方向的运动范围（ROM），比较各组间的差异。结果：L3椎体爆裂骨折后L2~L4各方向的ROM明显增加，与损伤前比较均有显著性差异（P<0.05）；单纯经伤椎6钉固定组与附加横连接经伤椎6钉固定组各方向的ROM均明显减小，与骨折组相比均有显著性差异（P<0.05），在前屈、后伸、侧弯运动方向的ROM小于对照组，差异有显著性 （P<0.05），旋转方向上大于对照组（P<0.05）。两种固定方式在前屈、后伸、侧弯方向上的ROM无显著性差异（P>0.05），附加横连经伤椎6钉固定组较单纯经伤椎6钉固定组在旋转方向上的ROM小，差异有显著性（P<0.05）。结论：经伤椎椎弓根置钉短节段钉棒固定可提高骨折模型各个运动方向上的生物力学稳定性，附加横连经伤椎6钉固定技术较单纯经伤椎6钉固定技术在轴向旋转运动方向上可提供更强的力学稳定性。

英文摘要:

  【Abstract】 Objective：To investigate the biomechanical stability of transpedicular fixation via injured vertebra plus connector for short-segment instrumentation of the spinal fracture.Method：L3 vertebral body fracture model were made on 5 fresh calf lumbar spine specimens，the stability of the L2-L4 segment with regard to intact specimens（control group），fractured model specimens（fracture group），transpedicular fixation via injured vertebra（6-screws construct） and transpedicular fixation via injured vertebra plus connector（6-screws plus connector construct） were tested for the range of motion（ROM） in flexion-extension，lateral bending and axial rotation.Result：The ROM of L2-L4 in flexion-extension，lateral bending and axial rotation of the fracture group was more than the intact specimens，which showed significant difference（P<0.05）.The ROM in flexion-extension，lateral bending and axial rotation of 6-screw and 6-screws plus connector constructs was smaller than those of the fracture group（P<0.05）.Two instrumentation group exhibited a smaller ROM in flexion-extension and lateral bending compared with the intact specimens（P<0.05）.There was no siginificant difference in the flexion-extension and lateral bending ROM between two instrumentation groups（P>0.05），but 6-screw plus connector constructs had smaller axial rotation ROM than that 6-screws constructs alone（P<0.05）.Conclusion：Transpedicular fixation via injured vertebra can enhance the biomechanical stability of the short-segment pedicle fixation system.Additionally，transpedicular fixation via injured vertebra plus connector is superior than the single 6-screw construct in providing axial rotation stability.