End plate of the discovertebral joint: degenerative change in the elderly adult.

Degenerative change at the end plate of the discovertebral joint was studied in the elderly adult by correlating the histologic and radiographic findings. Undecalcified ground sections were made from 21 autopsied lumbar spines that demonstrated no evidence of disease except age-related osteoporosis. Histologic examination showed that the cartilaginous end plates were degenerated to various extents and were replaced by subchondral bone proliferation (endochondral bone formation) in the direction of the joint space. In advanced cases, this histologic finding was reflected in radiographs as a subchondral sclerotic zone protruding toward the disk space. The degree of end-plate change was positively correlated with disk-space narrowing and the vacuum phenomenon (degeneration of the nucleus pulposus) but not with osteoporosis and vertebral compression. Anatomically and functionally, this may be the most common form of degeneration at the discovertebral joint end plate. Further study will be necessary to clarify the process.