Age-related disk degeneration: preliminary report of a naturally occurring baboon model.

Anteroposterior and lateral radiographs of 126 adult baboons were reviewed. The mean age was 15.7 years (range 6-30 years). Evidence of disk degeneration, to include disk-space narrowing, osteophyte formation, endplate changes, and facet joint arthropathy, was noted, and a grading scale, grades 0-3, was used to assign each animal an overall grade for degree of disk degeneration. Lateral radiographs were measured in the area of maximal sagittal plane curvatures. Radiographic review demonstrated a strongly positive correlation between the age of the baboons and the degree of degenerative change (p less than 0.0001), between the degree of kyphosis and the degree of degenerative change (p less than 0.0001), and between the age of the animal and the degree of kyphosis (p less than 0.001). This pilot study demonstrates plain radiographic confirmation of a naturally occurring primate model of disk degeneration, the first such model described, and is the basis for further investigation into magnetic resonance imaging and histopathologic confirmation of this model.