Lumbosacral transitional vertebrae: incidence in a consecutive patient series.

BACKGROUND Great variability exists in the reported frequency of transitional vertebra in the general population as well as in symptomatic lumbar spine patients. OBJECTIVE To determine the occurrence rate of transitional vertebra in consecutive lumbar spine patients in our practice. DESIGN A prospective, observational study METHODS Plain films were viewed and the presence or absence of a lumbar transitional vertebra was documented. Transitional vertebrae were classified as incomplete or complete. RESULTS Of the 300 consecutive patients, 30% had a transitional vertebra. CONCLUSION Our percentage of patients with a transitional vertebra was higher than the percentages reported for the general population. This supports our belief that the alteration in mechanics caused by a transitional vertebra may at times contribute to pain generation. Additionally, as a transitional segment may not always be visualized on MRI, obtaining plain films prior to an injection or surgery will help prevent confusion over the appropriate level for the procedure.