新型一体化人工枢椎内固定系统的生物力学稳定性评价

Biomechanical stability of a new integrated artificial axis

中文关键词:  一体化人工枢椎  枢椎肿瘤  3D打印  生物力学

英文关键词:Prosthesis of axis  Atlantoaxial tumor  3D printing  Biomechanics

中文摘要:

  【摘要】 目的：评价新型一体化人工枢椎内固定系统的生物力学稳定性。方法：6具新鲜成人枕颈椎标本（C0～C6），剔除其周围肌肉组织，保留枕骨粗隆以下的骨性结构及其相连的韧带和关节囊，制作正常模型（正常组），用脊柱三维运动测试机测量C2节段的屈伸、侧屈及旋转三维运动范围（ROM）；然后将标本枢椎切除，分别进行前路一体化人工枢椎内固定系统重建结合后路枕颈融合固定（人工枢椎组）及前路异形钛网支撑结合后路枕颈融合固定（异形钛网组），测量各组C2节段的屈伸、侧屈及旋转三维ROM。多组间比较采用随机区组方差分析，两两间的比较采用SNK法。结果：新鲜尸体标本生物力学分析两种模拟枢椎切除重建内固定系统力学效能的最大活动度均出现在后伸状态。前屈工况下，三组C2节段的ROM有统计学差异（P<0.05），人工枢椎组和正常组无统计学差异（P>0.05），异形钛网组显著性大于人工枢椎组及正常组（P<0.05）；后伸工况下，三组C2节段的ROM无统计学差异（P>0.05）；左侧弯工况下，三组C2节段的活动度有统计学差异（P<0.05），人工枢椎组和正常组比较无统计学差异（P>0.05），异形钛网组显著性大于人工枢椎组及正常组（P<0.05）；右侧弯工况下，三组C2节段的ROM有统计学差异（P<0.05），人工枢椎组与正常组和异形钛网组比较无统计学差异（P>0.05），异形钛网组著性大于正常组（P<0.05）；左、右旋转工况下，三组C2节段的ROM均有统计学差异（P<0.05），人工枢椎组和异形钛网组均显著性大于正常组（P<0.05），异形钛网组均显著性大于人工枢椎组（P<0.05）。结论：新型一体化人工枢椎假体对比异形钛网重建枢椎具有更好的稳定性，为其临床应用提供了力学理论依据。

英文摘要:

  【Abstract】 Objectives: To investigate the biomechanical stability of a new integrated artificial axis. Methods: We took six fresh-frozen human cadaveric occipitocervical specimens(C0-C6), carefully removed the muscular tissue at the craniocervical junction and preserved the bony structures, ligaments and articular capsules ranging from occipital protuberance to C6 to establish the normal model(normal group). The 3D spine motion test was applied to measure the range of motion(ROM) at C2 under flexion and extension, lateral flexion and rotation conditions. After that, we resected the axis of the 6 specimens, and established integrated artificial cervical reconstruction combined with posterior occipital cervical fixation model(artificial axis group) and modified T-shaped harms cage reconstruction combined with posterior occipital and cervical fixation model(T-shaped Harms cage group) for each specimen respectively. The biomechanical stability was compared among the 3 groups in flexion, extension, lateral flexion and rotation. Statistical significance was analyzed using randomized block analysis of variance among the 3 groups, and Student-Newman-Keuls(SNK) post hoc pairwise comparisons between each two groups. Results: Biomechanical analysis of the fresh cadaveric specimens showed that of the two internal fixation system, the maximum motion was under the loads of extension. In flexion, the C2 ROM of the three groups was statistically different(P<0.05), and between the artificial axis group and the normal group there was no significant difference(P>0.05), while in modified T-shaped Harms cage group the statistical significance was greater than that of artificial axis group and normal group(P<0.05). There was no statistical difference in C2 ROM among the three groups in extension state(P>0.05). In left lateral flexion, the statistical analysis result was the same as in the flexion condition. Similarly, the C2 ROM of the three groups was statistically different in right lateral flexion(P<0.05), and there was no significant difference between artificial axis group and normal group as well as between artificial axis group and modified T-shaped Harms cage group(P>0.05), while the statistical significance of modified T-shaped Harms cage group was greater than that of normal group(P<0.05). In both left and right rotation conditions, the C2 ROM of the three groups was statistically different among the three groups(P<0.05), and the biomechanical stability of artificial axis group and modified T-shaped Harms cage group were better than that of normal group(P<0.05), whereas the statistical significance of modified T-shaped Harms cage was greater than that of artificial axis group(P<0.05). Conclusions: The reconstruction with the newly developed artificial axis prosthesis showed higher stability than T-shaped Harms cage, which provided a theoretical basis for clinical application.