Validation and application of an intervertebral disc finite element model utilizing independently constructed tissue-level constitutive formulations that are nonlinear, anisotropic, and time-dependent

JOURNAL OF BIOMECHANICS

卷:47

Article

Jacobs, Nathan T.¹  Cortes, Daniel H.²  Peloquin, John M.³  Vresilovic, Edward J.⁴  Elliott, Dawn M.² 

[1] Univ Penn, Dept Mech Engn & Appl Mech, Philadelphia, PA 19104 USA

[2] Univ Delaware, Biomed Engn Program, Newark, DE 19716 USA

[3] Univ Penn, Dept Bioengn, Philadelphia, PA 19104 USA

[4] Penn State Univ, Penn State Hershey Bone & Joint Inst, Hershey, PA 17033 USA

关键词: Intervertebral disc;    Biphasic;    Biphasic-swelling;    Degeneration;    Annulus fibrosus;    Nucleus pulposus;    Cartilaginous endplate;   

DOI  :  10.1016/j.jbiomech.2014.06.008

来源: Elsevier

【 摘 要 】

Finite element (FE) models are advantageous in the study of intervertebral disc mechanics as the stress-strain distributions can be determined throughout the tissue and the applied loading and material properties can be controlled and modified. However, the complicated nature of the disc presents a challenge in developing an accurate and predictive disc model, which has led to limitations in FE geometry, material constitutive models and properties, and model validation. The objective of this study was to develop a new FE model of the intervertebral disc, to validate the model's nonlinear and time-dependent responses without tuning or calibration, and to evaluate the effect of changes in nucleus pulposus (NP), cartilaginous endplate (CEP), and annulus fibrosus (AF) material properties on the disc mechanical response. The new FE disc model utilized an analytically-based geometry. The model was created from the mean shape of human L4/L5 discs, measured from high-resolution 3D MR images and averaged using signed distance functions. Structural hyperelastic constitutive models were used in conjunction with biphasic-swelling theory to obtain material properties from recent tissue tests in confined compression and uniaxial tension. The FE disc model predictions fit within the experimental range (mean +/- 95% confidence interval) of the disc's nonlinear response for compressive slow loading ramp, creep, and stress-relaxation simulations. Changes in NP and CEP properties affected the neutral-zone displacement but had little effect on the final stiffness during slow-ramp compression loading. These results highlight the need to validate FE models using the disc's full nonlinear response in multiple loading scenarios. (C) 2014 Elsevier Ltd. All rights reserved.

【 授权许可】

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