Morphologic study of lumbar vertebral osteophytes

Vertebral osteophytes are one of the principal radiographic diagnostic criteria for degenerative change in the lumbar spine. These osteophytes have been previously classified by morphologic features into two groups, the "traction spur" and the "claw spur." It has been stated that the traction spur is a sign of spinal instability.

Lumbar spines from 20 cadavers provided 120 vertebrae from T-11 to L-5 and 240 vertebral rims for study. The presence of osteophytes was determined by measurement with digital calipers. The type of osteophyte was then determined visually, using the Macnab classification.

Sixty vertebral rims were found to have significant osteophytes. Twenty-four vertebral rims had osteophytes of the claw type only, and 11 had osteophytes of the traction type only. Of the eight vertebrae with traction osteophytes alone and with the adjacent vertebra available for study, none had such a corresponding osteophyte.

Traction spurs and claw spurs frequently coexist on the same vertebral rim. This suggests that they may result from the same degenerative process and do not necessarily reflect the results of two distinct pathologic processes.