椎管重建对腰椎活动度影响的有限元分析△

Impact of internal fixations for lumbar canal reconstruction on segmental range of motion: a finite element analysis

摘要:

[目的]比较椎板回植椎管重建内固定术对腰椎活动度范围(range of motion, ROM)的影响。[方法]分别建立腰椎 L_2~4三维有限元模型，包括正常模型组、椎板切除组、椎板回植 H 形钛板固定组(H 形钛板组)、椎板回植 L 形钛板固定组(L 形钛板组) 和椎板回植两孔钛板固定组 (两孔钛板组)。在 L₂椎体上施加 10 N · m 的应力，测量 6 种自由度下 L_2/3和 L_3/4节段 ROM。[结果] 总体方面，5 组模型的 6 种自由度比较，L_2/3 ROM 由大至小均依次为：左侧弯＞前屈＞右侧变＞后伸＞右旋＞左旋， L_3/4为：前屈＞左侧弯＞右侧变＞后伸＞右旋＞左旋，总体差异均有统计学意义 (P＜0.05)。 6 种自由度的五组模型比较，L_2/3和 L_3/4 的 ROM 由大至小均依次为：椎板切除组＞两孔钛板组＞ L 形钛板组＞ H 形钛板组＞正常模型组，总体差异均有统计学意义 (P＜ 0.05)。左弯、右弯、左旋和右旋状态下，H 形钛板的 ROM 显著小于 L 形钛板组和两孔钛板组(P＜0.05)。[结论]椎管重建可有效减少椎板切除所致的异常节段的活动度增加，且 H 形钛板固定重建椎管在抗弯曲和旋转时，其生物力学稳定性要优于 L 型和两孔钛板。

关键词:椎板切除;椎板回植;椎管重建;活动度;有限元分析

Abstract:

[Objective] To compare the influence of lamina replantation with different internal fixations for spinal canal reconstruction on segmental range of motion (ROM) of the lumbar spine. [Methods] The lumbar L_2~4 three-dimensional finite element models were estab- lished respectively, including normal model group (NM group) , laminectomy group (LE group) , laminectomy and H-shaped titanium plate fixation group (H-plate group), laminectomy and L-shaped titanium plate fixation group (L-plate group) and laminectomy and two-hole tita- nium plate fixation group (TH plate group) . A 10 Nm loading was applied to the L₂ vertebral body, the ROMs of L_2/3 and L_3/4 segments in six degrees of freedom were measured. [Results] In terms of overall comparison among the 6 degrees of freedom, the ROMs of L_2/3 were ranked in descending order: left bending ＞ forward flexion ＞ right bending ＞ extension ＞ right rotation ＞ left rotation, with statistically significant overall difference in all the 5 model groups (P＜0.05) . The ROMs of L3/4 were ranked in descending order: forward flexion ＞ left bending ＞ right bending ＞ extension ＞ right rotation ＞ left rotation, with statistically significant overall difference in all the 5 model groups (P＜0.05) . However, in terms of overall comparison among the 5 model groups, the ROM of L_2/3 and L_3/4 were arranged in descending order of: LE group ＞ TH plate group ＞ L-plate group ＞ H- plate group ＞ NM group, which all were statistically significant in 6 degrees of freedom (_P＜ 0.05) . In the left bending, right bending, left and right rotations, the ROM of H-plate group had significantly lower ROMs than that of Lplate group and TH plate group (P＜0.05) . [Conclusion] The lamina replantation with different internal fixations for spinal canal reconstruc- tion does effectively reduce the abnormal increase of segmental ROMs caused by laminectomy. Of them, H-shaped titanium plate fixation achieves better stability than L-shaped plate and two-hole titanium plate in terms of resistance of bending and rotation.

Key words:laminectomy; lamina replantation; spinal canal reconstruction; range of motion; finite element analysis