Lumbosacral transitional vertebra: relation to disc degeneration and low back pain.

STUDY DESIGN: Cross-sectional magnetic-resonance imaging (MRI) study. OBJECTIVE To investigate the relation of the lumbosacral transitional vertebra to signs of disc degeneration in MRI and to low back pain (LBP).

SUMMARY OF BACKGROUND DATA: An association between the transitional vertebra and herniation in the disc above has been found in patients with LBP, but knowledge of the relation to other degenerative disc changes detected in MRI and to LBP is lacking.

METHODS: MR images of the lumbar spine of 138 middle-aged working men and 25 healthy young men were evaluated. The presence and type of lumbosacral transitional vertebra and of degenerative changes in intervertebral discs were evaluated. The history of low back symptoms was obtained with a questionnaire from the middle-aged men.

RESULTS: The prevalence of transitional vertebra was 30%. Transitional vertebra was associated with an increased risk of degenerative changes in the disc above among the young men and with a decreased risk in the disc below among the middle-aged men. Transitional vertebra, symmetric or asymmetric, was not associated with any type of LBP in the middle-aged men.

CONCLUSIONS: Lumbosacral transitional vertebra increases the risk of early degeneration in the upper disc. This effect seems to be obscured by age-related changes in the middle age. The degenerative process is slowed down in the lower disc. For these effects, the presence of a transitional vertebra should be noticed when morphologic methods are used in research on lumbosacral spine. Transitional vertebra is not associated with any type of LBP.