TIME-COURSE OF RADIOLOGIC LESIONS IN SPINAL HYPEROSTOSIS - AN OSTEORADIOMETRIC STUDY

The purpose of this study was to evaluate changes over time in the flo wing spinal ossification characteristic of spinal hyperostosis. Thirty -two patients were studied. A QR-ORM osteoradiometry apparatus was use d to measure variations in the surface area of the ossification on rad iographs obtained after three, ten, and 20 years. The size of the ossi fication increased gradually in every case. Patients with a small ossi fication on the initial radiograph and younger patients were more like ly to have larger ossification size increases over time; male gender a nd diabetes mellitus had a similar effect, although the differences we re not significant, perhaps because of the small number of subjects. T he magnitude of the ossification increase was not the same on the ante roposterior and lateral films at the various time points. The rate of ossification increase was slower in patients with long-standing diseas e or osteoporosis, although differences were not statistically signifi cant. Over time, the density of the ossification increased, particular ly near the vertebral bodies, perhaps as a result of transformation of fibrocartilage tissue into compact bone tissue.