Influence of structural and material property uncertainties on biomechanics of intervertebral discs - Implications for disc tissue engineering. (October 2021)

• Record Type: Journal Article
• Authors: Wang, Wei; Zhou, Chaochao; Guo, Runsheng; Cha, Thomas; Li, Guoan
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 122(2021)
• Publication Date: 2021-10
• Subjects: Stochastic finite element model -- Intervertebral disc biomechanics -- Sensitivity analysis -- Tissue engineering -- Lumbar spine; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2021.104661
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: This study investigated how variations of structural and material properties of human intervertebral discs (IVDs) affect the biomechanical responses of the IVDs under simulated physiological loading conditions using a stochastic finite element (SFE) model. An SFE method, which combined an anatomic FE model of human lumbar L3-4 segment and probabilistic analysis of its structural and material properties, was used to generate a dataset of 500 random disc samples with varying structural and material properties. The sensitivity of the biomechanical responses, including intervertebral displacements/rotations, intradiscal pressures (IDP), fiber stresses and matrix strains of annulus fibrosus (AF), were systematically quantified under various physiological loading conditions, including a 500N compression and 7.5Nm moments in the 3 primary rotations. Significant variations of the IDPs, IVD displacements/rotations, and stress/strain distributions were found using the dataset of 500 ramdom disc samples. Under all the loading conditions, the IDPs were positively correlated with the Poisson's ratio of the NP (r = 0.46 to 0.75, p = 0.004–0.001) and negatively with the Young's modulus of the annulus matrix (r = −0.48 to −0.65, p = 0.003–0.001). The primary intervertebral rotations were significantly affected by the Young's modulus of the annulus matrix (r = −0.44 to −0.71, p = 0.001–0.032) and the orientations of the annular fibers (r = −0.45 to −0.69, p = 0.001–0.029). The heterogeneity of structures and material properties of the IVD had distinct effects on the biomechanical performances of the IVD. These data could help improve our understanding of the intrinsic biomechanics of the IVD and provide references for optimal design of tissue engineered discs by controlling structural and material properties of the disc components. Graphical abstract: The procedure of stochastic finite element modeling for sensitivity analyses of disc mechanical behavior to disc material and structural properties. Image 1 Highlights: Biomechanical responses of the disc were sensitive to the changes of disc tissue structural and material properties. The changes of the Young's modulus of annulus matrix and fiber orientations had the strongest influence. Disc mechanical behavior was more sensitive to the changes of fiber orientations than fiber tensile properties. Tissue-engineered discs can be optimally designed by controlling structural and material properties of certain components.