Verification of a numerical model for simulating intervertebral disc pathophysiology

Intervertebral disc (IVD) degeneration may cause low back pain which has a tremendous impact on the society and economy in the United States. It is important to quantitatively and qualitatively evaluate its pathophysiology in order to diagnose and treat disc degeneration. Recently, we have developed a multiphasic computational model for investigating cell mediated disc degeneration as well as exploring new strategies for disc therapies. The objective of this study was to verify this new computational model according to the guidelines of ASME V&V40. The model was discretized with finite element method and implemented in COMSOL Multiphysics. Several benchmark problems and method of manufactured solutions (MMS) were used to verify the numerical implementation. For all the benchmark problems tested, the numerical results were in excellent agreement with those analytical solutions or other numerical solutions. In addition, the observed convergence rates of primary unknowns obtained with MMS were in excellent agreement with theoretical convergence rates. This study showed that our model has been verified and found no evidence of coding errors.