OBJECTIVETo investigate the mechanical changes of the degenerated lumbar disc with finite element analysis.

METHODSA three dimensional finite element model of a human lumbar spine at the L3-L4 disc was established by the software MIMICS and ABAQUS based on computer tomography images. Degeneration was modeled by changes in geometry and material properties. The model was loaded with 0.3 MPa in axial plane. The von Mises stress on the annulus fiber, nucleus pulposus, endplate and facet joints in healthy and degenerated discs was compared.

RESULTCompared with healthy discs, the von Mises stress of disc distributed in the side of annulus fiber, the stress of nucleus pulposus decreased remarkably, the stress of endplate distributed in the posterior part, and the stress of facet joints increased for the degenerated disc.

CONCLUSIONThe finite element models can provide a method of understanding the relationship between biomechanical performance of the disc due to disc degeneration.