An axisymmetric poroelastic model for description of the short-term and long-term creep behavior of L4-L5 intervertebral disc

Understanding the relationship between different kinds of mechanical loading and the failure of the intervertebral disc is difficult to study in vivo and in vitro. Through finite element studies some of these issues may be overcome enabling more detailed assessment of the biomechanical behavior of the intervertebral disc. The objective of this paper is to develop a nonlinear axisymmetric poroelastic finite element model of intervertebral disc and show its capability for studying the time-dependent response of disc. After comparison of the response of different models in quasi-static analysis, the poroelastic model of intervertebral disc is presented and the results of a short-term and long-term creep tests were compared with experimental data. The results of the poroelastic model are in agreement with experimental ones reported in the literature hence this model can be used to study how different dynamic loading regimes are important as risk factors for initiation of intervertebral disc degeneration.