胸椎椎弓根根外内固定三维稳定性生物力学实验研究

目的:对比研究两种胸椎弓根根外内固定方法及椎弓根固定方法的三维稳定性,评价胸椎弓根根外内固定的生物力学效果。方法:新鲜胸椎标本14个;随机分为2组(A组:螺钉D=5.5mm,L=40mm;B组:螺钉D=6.5mm,L=50mm),7种固定状态模型。分别测试各状态的三维运动范围(ROM),并统计学分析对比。结果:A组,前屈后伸稳定性排列顺序:M2>M3>M4>M1,左右侧弯:M2>M3>M4>M1,轴向运动:M2>M3>M4>M1,其中M2,M3差异无显著统计学意义(P>0.05);B组,前屈后伸稳定性顺序:M6>M7>M5>M1,左右侧弯:M6>M7>M5>M1,左右旋转:M7>M6>M5>M1,其中M6,M7差异无显著统计学意义(P>0.05)。结论:使用较粗较长的螺钉固定时,胸椎弓根根外内固定三维稳定性优于椎弓根固定,有较好的生物力学效果。

The biomechanical stability of the thoracic extrapedicular fixation: An 3D ROM experiment

Objective: To compare the biomechanical stability of the thoracic extrapedicular fixation method with that of the transverse process-vertebra, the modified costre-transverse process and the transpedicular technique. Methods: 14 fresh thoracic specimens were divided into two groups (group A with screws of D /5.5mm and L/ 40mm, group B of D/6.5mm and L /50mm) and underwent seven fixation models; The ROM of different models in three different techniques were tested and compared separately. Results: In group A, the stability of the flexion/extension was M2>M3>M4>M1, the stability of the right and left bending M2>M3>M4>M1, and the stability of the rotation M2>M3>M4>M1, with no significant difference between M2 and M3; In group B, the stability of the flexion/extension was M6> M7> M5>M1, the stability of right and left bending M6> M7> M5>M1, and the stability of the rotation M7 > M6 > M5>M1, with no significant difference between M6 and M7. Conclusions: Adopting the wider and longer screws, extrapedicular fixation has the better biomechanical stability than that of transpedicular fixation.