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.