腰椎峡部裂机翼型记忆合金节段内固定器的生物力学评价

目的　评价一种新型腰椎峡部裂机翼型记忆合金节段内固定器的生物力学性能，为其临床应用提供理论依据。 方法　采用8例新鲜猪腰椎标本的L4/5脊柱功能单元进行生物力学实验，先后制作正常脊柱组、峡部裂组、Buck螺钉固定组、Nicol钢丝捆绑组、机翼型记忆合金固定组5组实验模型。利用脊柱三维运动实验机，分别测试5组模型在前屈/后伸、左/右侧弯及左/右轴向旋转6种运动的活动范围。 结果　在前屈/后伸及左/右旋转状态下，峡部裂组稳定性最差，同其他4组有显著差异（P<0.05）。而使用机翼型记忆合金节段内固定器可明显恢复峡部裂腰椎稳定性，同正常脊柱组及其他2种内固定组无显著差异（P>0.05）。在左/右侧弯状态下5组腰椎标本均无显著性差异（P>0.05）。 结论　该新型记忆合金内固定器可维持峡部裂腰椎正常的三维运动稳定性，并且操作简单，具有很好的应用前景。

Biomechanical evaluation of the aliform memory alloy intrasegmental fixation instrument for lumbar spondylolysis

Objective　To evaluate the biomechanical properties of the aliform memory alloy intrasegmental fixation instrument (AMAIFI) for lumbar spondylolysis.　Methods　L4/5 functional spinal units from 8 fresh pig cadavers were used in the test, which were grouped into: the normal spine group, the lumbar spondylolysis group, the Buck's screw group, the Nicol's wire fixation group and the aliform memory alloy the intrasegmental fixation group. The movement range of each group was measured under the kinetic state of flexion/extension, left/right lateral bending, and left/right axial rotation.　Results　Under the state of flexion/extension and left/right axial rotation, the stability of the lumbar spondylolysis group was the worst，and had a significant difference with the other groups (P<0.05). The stability of spondylolysis lumbar could be restored distinctly in the group fixed with AMAIFI, and had no significant difference with the normal spine group and the other 2 intrafixation groups (P>0.05). Under the state of the left/right lateral bending，there was no significant difference among the various groups (P>0.05). 　Conclusions　The newly designed AMAIFI can restore the stability of spondylolysis lumbar with its operationf; Consequently, it can be assumed hat AMAIFI has a better application in the future.