骶骨倾斜角与腰椎峡部应力相关性有限元分析

Finite element analysis of the correlation between sacral slope and lumbar isthmus stresses

目的基于有限元分析研究不同骶骨倾斜角(SS)在不同运动状态下对腰椎峡部存在的力学机制的影响。方法研究于2021年11月3日于新疆军区总医院完成CT数据扫描,利用Mimics、3-matic构建不同SS的腰骶模型,将其分为SS=30°组、SS=35°组、SS=40°组、SS=45°组、SS=50°组,利用Solidworks进行椎间盘,软骨重建,在Ansys有限元软件中模拟直立、前屈、后伸、侧弯,轴向旋转、前屈+侧弯、前屈+轴向旋转、后伸+侧弯、后伸+轴向旋转运动状态。多组间均数比较采用One-way ANOVA分析。结果第五腰椎-第一骶骨(L5-S1)活动度随SS增加呈上升趋势:SS=50°组高于SS=45°组[(2.81±1.33)°比(2.35±1.36)°,F=101.72,P<0.01],SS=45°组高于SS=40°组[(2.35±1.36)°比(1.86±0.92)°,F=52.35,P<0.01],SS=40°组高于SS=35°组[(1.86±0.92)°比(1.52±0.86)°,F=16.42,P<0.05],SS=35°组高于SS=30°组[(1.52±0.86)°比(1.32±0.63)°,F=11.52,P<0.05],差异均有统计学意义。L5峡部应力随着SS增加呈先下降后上升趋势:SS=30°组高于SS=35°组[(11.42±2.13)Mpa比(10.12±2.63)Mpa,F=434.52,P<0.01],SS=35°组高于SS=40°组[(10.12±2.63)MPa比(9.65±2.48)MPa,F=68.32,P<0.01],SS=40°组高于SS=45°组[(9.65±2.48)MPa比(9.23±1.72)MPa,F=13.92,P<0.01],SS=45°组低于SS=50°组[(9.23±1.72)MPa比(12.65±2.22)MPa,F=1168.32,P<0.01],差异均有统计学意义。结论过高或过低的骶骨倾斜角会提升或限制L5椎体的活动能力、产生峡部应力增加,从而增加了峡部断裂的风险。

Objective To investigate the effects of different sacral slope(SS)with various motion states on the mechanical mechanisms in the lumbar isthmus based on finite element analysis.Methods CT data scans were conducted at the Xinjiang Military Region General Hospital on November 3,2021.The lumbosacral models of different SSs were constructed by using Mimics and 3-matic,and they were divided into SS=30°group,SS=35°group,SS=40°group,SS=45°group and SS=50°group.Solidworks was employed for intervertebral disc and cartilage reconstruction.Ansys finite element software was utilized to simulate motion states of stand,forward flexion,rearward extension,lateral bending,axial rotation,forward flexion+lateral bending,forwardflexion+axial rotation,rearward extension+lateral bending,and rearward extension+axial rotation.The analysis of averages of multiple groups were compared with One-way ANOVA.Results The range of motion for the lumbar 5-sacral 1(L5-S1)segment increased with the increment of SS:SS=50°group was higher than SS=45°group[(2.81±1.33)°vs.(2.35±1.36)°,F=101.72,P<0.01],SS=45°group was higher than SS=40°group[(2.35±1.36)°vs.(1.86±0.92)°,F=52.35,P<0.01],SS=40°group was higher than SS=35°group[(1.86±0.92)°vs.(1.52±0.86)°,F=16.42,P<0.05],and SS=35°group was higher than SS=30°group[(1.52±0.86)°vs.(1.32±0.63)°,F=11.52,P<0.05].All differences of the above were statistically significant.With increasing SS,The stress of isthmus exhibited a trend of initial decrease followed by an increase:SS=30°group was higher than SS=35°group[(11.42±2.13)MPa vs.(10.12±2.63)MPa,F=434.52,P<0.01],SS=35°group was higher than SS=40°group[(10.12±2.63)MPa vs.(9.65±2.48)MPa,F=68.32,P<0.01],SS=40°group was higher than SS=45°group[(9.65±2.48)MPa vs.(9.23±1.72)MPa,F=13.92,P<0.01],and SS=45°group was lower than SS=50°group[(9.23±1.72)MPa vs.(12.65±2.22)MPa,F=1168.32,P<0.01].All differences of the above were statistically significant.Conclusion Excessive or insufficient sacral slope may enhance or restrict the mobility of the L5 vertebral,leading to increased stress in the isthmus region and consequently elevating the risk of fractures in isthmus region.