|Biomechanics; Biomechanics; Spine; Vertebra; Intervertebral disc; Intraidiscal pressure
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Intervertebral disc (IVD) degeneration is strongly associated with back pain, and affects approximately 60% of the population by age 70. Furthermore, it has been suggested that this degeneration may play an important role in the initiation or perpetuation of vertebral fractures. Given that the IVD is a primary load-bearing structure in the spine, the change of intradiscal pressure (IDP) over time that accompanies disc degeneration provides a functional measure of the disease pathology. Studies show that both an overall decrease in IDP magnitude and changes in the spatial distribution of IDP are found with increasing levels of degeneration. Thus, the overall goal of this study was to determine the correlation between the spatial distributions of IDP, as measured along both mid-sagittal and mid-coronal paths, and a clinically feasible assessment of disc health. Disc degeneration was assessed non-invasively using quantitative computed tomography (QCT). A custom, electro-mechanical device was designed, manufactured and assembled to measure IDP distributions. The results indicated that the spatial distribution of IDP was most homogenous for the nucleus pulposus (NP) region regardless of load type and disc health grade. Mean IDP tended to be lowest in severely degenerated discs, consistent with earlier findings that axial loads in spinal columns with degenerated IVDs shift from the disc to the neural arch in both flexural and erect postures.