引言
1 腰椎有限元模型的建立
1.1 腰椎完整模型
1.2 不同内固定方案模型
表 1 有限元模型的材料属性Table 1 Material properties of finite element model |
| 材料名称 | 弹性模量/MPa | 泊松比 | 刚度/(N·mm-1) |
| 皮质骨 | 12 000 | 0.30 | |
| 松质骨 | 100 | 0.20 | |
| 纤维环 | 4.20 | 0.45 | |
| 髓核 | 1 | 0.49 | |
| 终板 | 4 000 | 0.30 | |
| 软骨 | 10 | 0.30 | |
| 前纵韧带 | 8.74 | ||
| 后纵韧带 | 5.83 | ||
| 棘上韧带 | 15.38 | ||
| 棘间韧带 | 0.19 | ||
| 黄韧带 | 15.75 | ||
| 横突间韧带 | 2.39 | ||
| 椎弓根螺钉、连接棒 | 110 000 | 0.28 | |
| 融合器 | 3 600 | 0.25 | |
| 骨水泥 | 298 | 0.30 |
2 有限元分析的结果与讨论
2.1 模型验证
2.2 内固定系统的应力
2.3 相邻节段椎间盘的应力
图 9 不同内固定方案中L3-L4椎间盘的应力分布云图Fig. 9 Stress distribution contours of the L3-L4 intervertebral disc for different internal fixation schemes |
图 10 不同内固定方案中L4-L5椎间盘的应力分布云图Fig. 10 Stress distribution contours of the L4-L5 intervertebral disc for different internal fixation schemes |
2.4 椎间的活动度
表 2 不同内固定方案中相邻节段的ROM比较Table 2 Comparison of ROM values of adjacent segments for different internal fixation schemes |
| 生理活动 | ROM/(°) | |||||
| L1-L2 | L2-L3 | L3-L4 | L4-L5 | L5-S1 | 腰椎ROM总量 | |
| 前屈 | ||||||
| 完整模型 | 3.12 | 3.55(100%) | 4.21(100%) | 4.27(100%) | 2.72(100%) | 17.87 |
| A组 | 2.00 | 1.87(52.7%) | 1.68(40.0%) | 1.90(44.5%) | 0.16(5.9%) | 7.61 |
| B组 | 2.01 | 1.88(53.0%) | 1.67(39.7%) | 0.30(7.0%) | 0.06(2.2%) | 5.92 |
| C组 | 1.99 | 0.70(19.7%) | 0.61(14.5%) | 0.67(15.7%) | 0.09(3.3%) | 4.06 |
| 后伸 | ||||||
| 完整模型 | 2.73 | 3.70(100%) | 3.01(100%) | 3.68(100%) | 1.85(100%) | 14.97 |
| A组 | 1.82 | 2.55(68.9%) | 2.76(91.7%) | 2.54(69.0%) | 0.14(7.6%) | 9.81 |
| B组 | 1.82 | 2.57(69.5%) | 2.77(92.0%) | 0.52(14.1%) | 0.31(16.8%) | 7.99 |
| C组 | 1.68 | 1.37(37.0%) | 0.84(27.9%) | 0.55(14.9%) | 0.07(3.8%) | 4.51 |
| 侧弯 | ||||||
| 完整模型 | 2.56 | 3.83(100%) | 3.23(100%) | 2.75(100%) | 0.96(100%) | 13.33 |
| A组 | 1.74 | 2.14(55.9%) | 2.06(63.7%) | 0.88(32.0%) | 0.13(13.5%) | 6.95 |
| B组 | 1.76 | 2.15(56.1%) | 1.94(60.1%) | 0.18(6.5%) | 0.04(4.2%) | 6.07 |
| C组 | 1.74 | 1.37(35.8%) | 1.57(48.6%) | 0.85(30.9%) | 0.11(11.5%) | 5.64 |
| 扭转 | ||||||
| 完整模型 | 1.77 | 2.00(100%) | 1.75(100%) | 2.17(100%) | 1.04(100%) | 8.73 |
| A组 | 1.77 | 1.97(98.5%) | 1.78(101.7%) | 1.21(55.7%) | 0.07(6.7%) | 6.80 |
| B组 | 1.78 | 1.97(98.5%) | 1.87(106.9%) | 0.24(11.1%) | 0.08(7.7%) | 5.84 |
| C组 | 1.77 | 1.44(72.0%) | 1.36(77.7%) | 0.77(35.5%) | 0.07(6.7%) | 5.41 |
括号表示以下值:(完整模型、模型A、模型B或模型C的ROM/完整模型的ROM)×100% |
