To date, no study has demonstrated the potential in vivo effects of growth factors on the intervertebral disc. The present study reports that the intradiscal administration of osteogenic protein-1 in vivo results in an increased disc height present at 2, 4, and 8 weeks and an increase in PG content of the nucleus pulposus at the 2-week time point. Therefore, osteogenic protein-1 may act to stimulate metabolic activity in the nucleus pulposus. Continued research is needed to evaluate the potential of growth factor-induced reversal of age-related disc degeneration in an appropriate animal model. In addition, studies in a nonhuman primate animal model will be essential before considering intradiscal injection of growth factors in humans.

No abstract

Because the structure, maturation, and degeneration of canine intervertebral disks resemble those of humans, the authors developed a model of acute intervertebral disk degeneration in dogs. Herniated disks of 18 dogs were examined with magnetic resonance (MR) imaging and then sectioned with a freezing microtome. On the basis of their morphologic appearance in the freezing microtome sections, most of the lumbar intervertebral disks could be categorized as one of six types. Each type has characteristic features and a distinctive appearance on MR images. Findings of this study--including decreased signal intensity from the intervertebral disk, altered signal intensity in contiguous bone marrow, bulging of the anulus fibrosus, herniation of the nucleus pulposus, and contrast enhancement after intravenous administration of gadolinium diethylenetriaminepentaacetic acid (DTPA)--resemble observations from human clinical studies. Classification of degenerating disks and identification of MR imaging characteristics of each type may improve the interpretation of MR images and recognition of early disk degeneration in humans.

No abstract

No abstract