Intervertebral Disc Shape Variation and its Relationship to Degeneration Using Principal Components Analysis of a Population of MR Images

Degeneration of the intervertebral disc (IVD) is implicated in low back pain, which is a costly and prevalent disease. Since the IVD is a mechanically active organ, it is important to consider its mechanical behavior as one factor in the degenerate pathology. Strain can be measured directly by imaging methods, but the stress distribution within the disc must be calculated. The stress distribution for a particular strain state is dependent on the IVD’s material properties and its geometry. While the material properties of the tissues comprising IVD have been extensively studied, its three-dimensional geometry remains incompletely characterized. Prior whole-disc models have been constructed from single IVDs. While this approach ensures that the geometry has a physiological basis, it is uncertain the degree to which results from a single IVD shape can be generalized to the entire population.