Dimbath Elizabeth D, Morino Concetta, Middleton Shea, Kait Jason, Ortiz-Paparoni Maria, Slotkin Theodore A, Luck Jason F, Bass Cameron R 'Dale'
Department of Biomedical Engineering, Duke University, 101 Science Dr, 1427 FCIEMAS Bldg, Box 90281, Durham, NC, 27708, USA.
Department of Mechanical Engineering and Material Science, Duke University, Durham, NC, 27708, USA.
Ann Biomed Eng. 2024 Aug 4. doi: 10.1007/s10439-024-03595-w.
This study aims to explore how cyclic loading influences creep response in the lumbar spine under combined flexion-compression loading.
Ten porcine functional spinal units (FSUs) were mechanically tested in cyclic or static combined flexion-compression loading. Creep response between loading regimes was compared using strain-time histories and linear regression. High-resolution computed tomography (µCT) visualized damage to FSUs. Statistical methods, ANCOVA and ANOVA, assessed differences in behavior between loading regimes.
Cyclic and static loading regimes exhibited distinct creep response patterns and biphasic response. ANCOVA and ANOVA analyses revealed significant differences in slopes of creep behavior in both linear phases. Cyclic tests consistently showed endplate fractures in µCT imaging.
The study reveals statistically significant differences in creep response between cyclic and static loading regimes in porcine lumbar spinal units under combined flexion-compression loading. The observed biphasic behavior suggests distinct phases of tissue response, indicating potential shifts in load transfer mechanisms. Endplate fractures in cyclic tests suggest increased injury risk compared to static loading. These findings underscore the importance of considering loading conditions in computational models and designing preventive measures for occupations involving repetitive spinal loading.
本研究旨在探讨在屈曲 - 压缩联合载荷作用下，循环加载如何影响腰椎的蠕变反应。
对10个猪功能性脊柱单元（FSU）进行循环或静态屈曲 - 压缩联合载荷的力学测试。使用应变 - 时间历程和线性回归比较不同加载方式下的蠕变反应。高分辨率计算机断层扫描（µCT）观察FSU的损伤情况。采用协方差分析（ANCOVA）和方差分析（ANOVA）统计方法评估不同加载方式下行为的差异。
循环加载和静态加载方式呈现出不同的蠕变反应模式和双相反应。ANCOVA和ANOVA分析显示，两个线性阶段的蠕变行为斜率存在显著差异。循环测试在µCT成像中始终显示终板骨折。
该研究揭示了在屈曲 - 压缩联合载荷作用下，猪腰椎脊柱单元的循环加载和静态加载方式在蠕变反应上存在统计学显著差异。观察到的双相行为表明组织反应存在不同阶段，提示载荷传递机制可能发生潜在变化。循环测试中的终板骨折表明与静态加载相比，损伤风险增加。这些发现强调了在计算模型中考虑加载条件以及为涉及重复性脊柱载荷的职业设计预防措施的重要性。
