短节段腰椎滑脱复位固定器的生物力学评价

Biomechanical evaluation of the ped icle screw system in the treatment of lumbar spondylolisthesis

目的评价腰椎滑脱复位固定器(HOIST)的生物力学性能。方法采用7具新鲜成人尸体脊柱标本(L2～S2),Panjabi法制作腰椎滑脱模型,固定器械分别为HOIST器械和DICK器械。应用脊柱三维运动稳定测试仪对标本进行前屈,后伸,右、左侧弯及左、右轴向旋转6个方位的运动范围(ROM)测试;在858MTS实验机上进行疲劳实验。实验分为完整状态组、L4滑脱组、HOIST器械固定组、HOIST器械疲劳组和DICK器械组。结果滑脱状态的ROM明显大于其他4个状态(P<0.05);HOIST器械固定疲劳前后的标本(L4,5)在6个方位的ROM明显较完整状态小(P<0.05);HOIST器械固定疲劳前后以及DICK器械固定三个状态间的ROM(除左轴向旋转外)差异无显著性意义(P>0.05)。结论HOIST器械在力学性能上能满足生理需要,且具有良好的疲劳后稳定性。

Objective To evaluate the biomechanical featu res of the HOIST in the treatment of lumbar spondylolisthesis.Methods Seven fresh cadaver specimens from L 2 to sacrum was used in the study.Each specimen was tested in five states:intact state as the control,spon dylolisthesis model by Panjabi meth od without fixation,spondylolisthesis model fixed with HOIST device,fatigued test of the HOIST and fixed with DICK system.During the experiment,the flexion,extension,bilateral bending and axial rotation loading we re applied to the specimens and measure d with three dimensional analysis ap paratus.A fatigue process of HOIST device was carried out with multifunctional test system(MTS 858,American).The ranges of motion(ROM)of spinal segments were determined with two special cameras and t test was used in statistical analysis.Results The ROM in spondylolisthesis state was significantly greater than that o f the others(P<0.05).Diminution of fixation with HOIST device were statistic significant (P<0.05)either pre-fatigue or post-fatigue compared with intact specimens.The delimitation between the ROM of DICK system and that of intact was notable(P<0.05),which did not include left axial rotation(P>0.05).The difference among two HOIST grou ps and DICK group was not significant at the0.05level except the ROM of left axia l rotation(P<0.05).Con-clusion Although the biomechanical effects of HOIST device may not be superior to that of DICK,the force of HOIST device can reach the physiological need.[