Finite element comparison between the human and the ovine lumbar intervertebral disc.

INTRODUCTION: Nowadays it is still not clear which loading conditions are responsible for lumbar intervertebral disc failure. Many studies have been conducted to investigate the effect of different loading conditions on the herniation processes, and many of them were based on the ovine model. However, the biomechanical similarities between the human and the ovine lumbar disc have been demonstrated in the main planes only, whereas it is not known if they are comparable under complex loading conditions too. The aim of this study was to compare the mechanical response of the ovine and the human lumbar intervetebral disc under complex loading conditions, in order to investigate differences and similarities between the species.The loading scenarios described in a finite element study on a human lumbar segment were applied to a model of the ovine disc, and the results were then compared.It has been shown that combined loads generated highest strains in both the models, and the maximum strains had the same location in the posterior or in the postero-lateral region of the annulus, according to the loading scenario.
CONCLUSION: The ovine disc can be used in spinal research to investigate herniation process under any loading conditions. LEVEL OF EVIDENCE: V.