Beijing key Laboratory for Design and Evaluation Technology of Advanced Implantable & Interventional Medical Devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
School of Big Data and Information, Shanxi Polytechnic Institute, Shanxi, China.
PLoS One. 2022 Jul 29;17(7):e0266954. doi: 10.1371/journal.pone.0266954. eCollection 2022.
Few studies have analyzed the different biomechanical properties of the lumbar with various morphological parameters, which play an important role in injury and degeneration. This study aims to preliminarily investigate biomechanical characteristics of the spine with different sagittal alignment morphotypes by using finite element (FE) simulation and in-vitro testing.
According to the lumbar-pelvic radiographic parameters of the Chinese population, the parametric FE models (L1-S1-pelvis) of Roussouly's type (1-4) were validated and developed based on the in-vitro biomechanical testing. A pure moment of 7.5 Nm was applied in the three anatomical planes to simulate the physiological activities of flexion, extension, left-right lateral bending and left-right axial rotation.
The sagittal configuration of four Roussouly's type models had a strong effect on the biomechanical responses in flexion and extension. The apex of the lumbar lordosis is a critical position where the segment has the lowest range of motion among all the models. In flexion-extension, type 3 and 4 models with a good lordosis shape had a more uniform rotation distribution at each motor function segment, however, type 1 and 2 models with a straighter spine had a larger proportion of rotation at the L5-S1 level. In addition, type 1 and 2 models had higher intradiscal pressures (IDPs) at the L4-5 segment in flexion, while type 4 model had larger matrix and fiber stresses at the L5-S1 segment in extension.
The well-marched lordotic type 3 lumbar had greater stability, however, a straighter spine (type 1 and 2) had poor balance and load-bearing capacity. The hypolordotic type 4 model showed larger annulus fiber stress. Therefore, the sagittal alignment of Roussouly's type models had different kinetic and biomechanical responses under various loading conditions, leading to different clinical manifestations of the lumbar disease.
很少有研究分析过不同形态参数对腰椎的不同生物力学特性的影响，这些特性在损伤和退变中起着重要作用。本研究旨在通过有限元（FE）模拟和体外测试初步研究不同矢状位排列形态类型脊柱的生物力学特征。
根据中国人群的腰椎骨盆影像学参数，基于体外生物力学测试，对 Roussouly 型（1-4）的参数 FE 模型（L1-S1-骨盆）进行了验证和开发。在三个解剖平面上施加 7.5 Nm 的纯力矩，以模拟屈伸、左右侧屈和左右轴向旋转的生理活动。
四种 Roussouly 型模型的矢状结构对屈伸运动的生物力学响应有很大影响。腰椎前凸的顶点是节段在所有模型中活动范围最小的关键位置。在屈伸运动中，具有良好前凸形状的 3 型和 4 型模型在每个运动功能节段的旋转分布更加均匀，然而，脊柱较直的 1 型和 2 型模型在 L5-S1 水平上的旋转比例更大。此外，在屈曲时，1 型和 2 型模型的 L4-5 节段椎间盘内压力（IDP）更高，而在伸展时，4 型模型的 L5-S1 节段基质和纤维的应力更大。
匹配良好的前凸型 3 腰椎具有更大的稳定性，然而，较直的脊柱（1 型和 2 型）平衡和承重能力较差。低前凸型 4 模型显示出更大的纤维环纤维应力。因此，Roussouly 型模型的矢状位排列在各种载荷条件下具有不同的运动学和生物力学响应，导致腰椎疾病的临床表现不同。
