The relationship between cartilage end-plate calcification and disc degeneration: an experimental study

Objective To study the relationship between cartilage end-plate calcificati on and intervertebral disc degeneration. Methods An experimental model of cervical disc degeneration in rabbits was established by resection of the cervical supraspinous and interspinous liga ments and detachment of the posterior paravertebral muscles from the cervic al vertebrae. Mechanical instability in the cervical spine elicited by this surgical intervention accelerated the process of intervertebral disc degen eration. The extent of intervertebral disc degeneration was graded in morph ologically, and the thicknesses of the calcified layer and the uncalcified layer of the cartilage end-plate were measured in each degenerated cervical disc. Results In less severely degenerative cervical discs, the morphology of the cartilage end-plate showed nearly normal construction, and the tidemark wa s clear. In severely degenerative discs, the matrix and cells showed fibros is, the tidemark advanced, and the calcified cartilage thickened. There exi sts a positive correlation between the thickness of the calcified layer of the cartilage end-plate and the degree of cervical disc degeneration. Conclusion The calcification of the cartilage end-plate is the key factor t hat initiates and promotes cervical disc degeneration.