腰椎棘突间动态稳定装置Coflex不同置入深度对相邻节段运动范围影响的生物力学研究

Adjacent segment range of motion after different insertion depth of lumbar interspinous dynamic stabilization device(Coflex): a biomechanical study

中文关键词:  腰椎  相邻节段  内固定器  假体置入  生物力学

英文关键词:Lumbar vertebrae  Adjacent segment  Internal fixators  Prosthesis implantation  Biomechanics

中文摘要:

  【摘要】 目的：探讨置入腰椎棘突间动态稳定装置Coflex不同深度后对上下相邻节段运动范围的影响。方法：将6具新鲜成人尸体腰椎标本（L1～L5）两端固定在生物力学测试系统上，以L3/4节段为手术节段，L2、L3、L4、L5椎体放置运动范围记录系统用以记录相邻节段（L2/3、L4/5）运动范围。分别对腰椎标本完整状态（保持腰椎韧带及小关节完整）、5mm状态（Coflex的U形顶端距离硬脊膜5mm）、0mm组（距离为0mm）分别加载8N·m的纯力矩进行生物力学测试，测试顺序为前屈、后伸、左右侧弯、左右侧旋，并记录相邻节段L2/3、L4/5的运动范围。对3组标本在6个方向的相邻节段（L2/3、L4/5）运动范围分别行单个因素的重复测量方差分析，两两对比采用LSD检验。结果：L2/3节段在前屈、后伸、左右侧弯、左右侧旋6个方向的运动范围，完整组分别为4.23°±0.25°、3.56°±0.14°、3.07°±0.12°、3.34°±0.08°、2.53°±0.16°、2.44°±0.11°；5mm组分别为4.40°±0.21°、3.64°±0.14°、3.09°±0.11°、3.35°±0.07°、2.54°±0.16°、2.46°±0.10°；0mm组分别为4.47°±0.20°、3.72°±0.16°、3.14°±0.10°、3.38°±0.08°、2.58°±0.15°、2.49°±0.12°；三组间差异均无统计学意义（P＞0.05）。L4/5节段三组标本在前屈、后伸、左右侧弯、左右侧旋6个方向的运动范围，完整组分别为3.80°±0.28°、3.45°±0.11°、3.25°±0.11°、3.28°±0.13°、2.44°±0.11°、2.42°±0.11°；5mm组分别为3.86°±0.28°、3.52°±0.11°、3.28°±0.09°、3.31°±0.05°、2.50°±0.07°、2.46°±0.09°；0mm组分别为3.90°±0.28°、3.59°±0.10°、3.32°±0.08°、3.36°±0.06°、2.52°±0.08°、2.48°±0.09°；三组间差异均无统计学意义（P＞0.05）。结论：腰椎棘突间动态稳定装置Coflex的U形顶端与硬脊膜的距离≤5mm时，上下邻近节段在前屈、后伸、左右侧弯、左右侧旋6个方向运动范围较完整状态无明显增加。

英文摘要:

  【Abstract】 Objectives: To evaluate the lumbar adjacent segment range of motion after different insertion depth of lumbar interspinous dynamic stabilization device(Coflex). Methods: Six fresh adult human cadaveric lumbar spine specimens(L1-L5) were fixed in a material testing system(MTS) by embedding to clamps with L1 and L5 vertebrae. L3/4 of each specimen was operated. The L2, L3, L4, L5 vertebra was inserted one spacer respectively which was used to record the range of motion(ROM) of the adjacent segments(L2/3, L4/5). Each lumbar spine specimen was tested according to the loading sequence at 3 groups: intact(keeping lumbar ligament and facet joint intact) group, 5mm insertion(distance between apex of U-shaped Coflex and dural sac was 5mm) group and 0mm insertion(distance was 0mm) group. Each lumbar spine specimen was loaded with pure moments of 8N·m according to a loading sequence consisting of flexion, extension, left/right lateral bend?鄄ing, left/right axial rotation and the ROM of adjacent segment was recorded. Adjacent segments(L2/3, L4/5) ROM of 3 groups in 6 directions was analyzed respectively with one-way ANOVA test and multiple comparisons were based on LSD method. Results: In L2/3 segment： the mean ROM of 3 groups was equal in flexion, extension, left/right lateral bending, left/right axial rotation(intact group: 4.23°±0.25°, 3.56°±0.14°, 3.07°±0.12°, 3.34°±0.08°, 2.53°±0.16°, 2.44°±0.11°; 5mm insertion group: 4.40°±0.21°, 3.64°±0.14°, 3.09°±0.11°, 3.35°±0.07°, 2.54°±0.16°, 2.46°±0.10°; 0mm insertion group: 4.47°±0.20°, 3.72°±0.16°, 3.14°±0.10°, 3.38°±0.08°, 2.58°±0.15°, 2.49°±0.12°), and there were no significant differences among 3 groups(all P>0.05). In L4/5 segment： the mean ROM of 3 groups was equal in flexion, extension, left/right lateral bending, left/right axial rotation (intact group: 3.80°±0.28°, 3.45°±0.11°, 3.25°±0.11°, 3.28°±0.13°, 2.44°±0.11°, 2.42°±0.11°; 5mm insertion group: 3.86°±0.28°, 3.52°±0.11°, 3.28°±0.09°, 3.31°±0.05°, 2.50°±0.07°, 2.46°±0.09°; 0mm insertion group: 4.47°±0.20°, 3.72°±0.16°, 3.14°±0.10°, 3.38°±0.08°, 2.58°±0.15°, 2.49°±0.12°), and there were no significant differences among 3 groups(all P>0.05). Conclusions: The adjacent segments after different insertion depth(when distance between apex of U-shaped Coflex and dural sac was or less than 5mm) of lumbar interspinous dynamic stabilization device(Coflex) allow no significantly more motion than the intact specimen in flexion, extension, left/right lateral bending, left/right axial rotation.