Wei Wenqing, Zhang Tianyuan, Yang Junlin, Qian Yu, Dong Yating
School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China.
Spine Surgery Center, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Front Bioeng Biotechnol. 2023 Feb 16;11:1111449. doi: 10.3389/fbioe.2023.1111449. eCollection 2023.
To study the mechanical sensitivity of different intervertebral disc and bone material parameters and ligaments under different force configurations and magnitudes in the scoliosis model. The finite element model of a 21-year-old female is built using computed tomography. Local range of motion testing and global bending simulations are performed for the model verification. Subsequently, Five force of different directions and configurations were applied to the finite element model applying the brace pad position. The material parameters of the model were related to different spinal flexibilities and included different material parameters of cortical bone, cancellous bone, nucleus and annulus. The virtual X-ray technique measured Cobb angle, thoracic Lordosis, and lumbar Kyphosis. The difference in peak displacement is 9.28 mm, 19.99 mm, 27.06 mm, 43.99 mm, and 50.1 mm under five force configurations. The maximum Cobb angle difference due to material parameters are 4.7° and 6.2°, which are converted to thoracic and lumbar in-brace correction difference of 18% and 15.5%. The maximum difference in Kyphosis and Lordosis angle is 4.4° and 5.8°. The average thoracic and lumbar Cobb angle variation difference in intervertebral disc control group is larger than that in bone control group, while the average Kyphosis and Lordosis angle is inverse. The displacement distribution of models with or without ligaments is similar, with a peak displacement difference of 1.3 mm in C5. The peak stress occurred at the junction of the cortical bone and ribs. Spinal flexibility largely influences the treatment effect of the brace. The intervertebral disc has a greater effect on the Cobb angle, the bone has a greater effect on the Kyphosis and Lordosis angles, and the rotation is affected by both. Patient-specific material is the key to increasing accuracy in the personalized finite element model. This study provides a scientific basis for using controllable brace treatment for scoliosis.
为研究脊柱侧弯模型中不同椎间盘、骨材料参数及韧带在不同力配置和大小下的力学敏感性。使用计算机断层扫描构建一名21岁女性的有限元模型。对该模型进行局部活动范围测试和整体弯曲模拟以进行模型验证。随后，在应用支具垫位置的情况下，向有限元模型施加五个不同方向和配置的力。模型的材料参数与不同的脊柱柔韧性相关，包括皮质骨、松质骨、髓核和纤维环的不同材料参数。虚拟X射线技术测量了Cobb角、胸椎前凸和腰椎后凸。在五种力配置下，峰值位移差异分别为9.28毫米、19.99毫米、27.06毫米、43.99毫米和50.1毫米。由于材料参数导致的最大Cobb角差异分别为4.7°和6.2°，转换为胸椎和腰椎支具内矫正差异分别为18%和15.5%。后凸和前凸角的最大差异分别为4.4°和5.8°。椎间盘对照组的胸椎和腰椎Cobb角平均变化差异大于骨对照组，而后凸和前凸角的平均值则相反。有或无韧带模型的位移分布相似，C5处的峰值位移差异为1.3毫米。峰值应力出现在皮质骨与肋骨的交界处。脊柱柔韧性在很大程度上影响支具的治疗效果。椎间盘对Cobb角影响较大，骨对后凸和前凸角影响较大，而旋转受两者影响。患者特异性材料是提高个性化有限元模型准确性的关键。本研究为使用可控支具治疗脊柱侧弯提供了科学依据。
