Mechanical behavior of a simple model of an intervertebral disk under compressive loading.

Abstract A simplified axisymmetric finite-element model of the vertebral body-intervertebral disk is constructed. The model employs three homogeneous substructures corresponding to the vertebral body/endplate region, the annulus fibrosis of the intervertebral disk, and the nucleus pulposis. The model is used to examine the effects of gross disk geometry and material property parameters on the predicted intradiscal pressure increase, radial disk bulge, and vertical deflection under compressive loading. The results obtained indicate that all parameters have a significant effect on disk bulge and vertical deflection. Variations of disk height and radius are found to produce significant changes in the predicted intradiscal pressure increase. Results obtained using the present simplified model are also shown to be in reasonable agreement with published experimental measurements.

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