UNLABELLED

Lumbosacral transitional vertebrae can alter the biomechanics of weight transfer at the affected spinal segment. Low-back pain may result. This study assessed what skeletal scintigraphy reveals about stress associated with a lumbosacral transitional vertebra in young patients with low-back pain.

METHODS

The study population included 48 patients (30 male, 18 female; age range, 6-19 y; mean age, 15.7 y) with low-back pain and a lumbosacral transitional vertebra. Skeletal scintigraphy was correlated with plain radiographs in all, CT in 12, and MRI in 11.

RESULTS

High uptake was shown at the articulation between the transverse process of a lumbosacral transitional vertebra and the sacrum in 39 (81%) of the patients. In 23 (59%) of the 39 patients with high uptake, this finding was shown only by SPECT. In 13 (81%) of the 16 for which the high uptake was shown by planar imaging, the anterior projection was more valuable than the posterior projection. In 9 (23%) of the 39 patients with high uptake at the transverse-sacral articulation, the lumbosacral transitional vertebra had not been noted in a radiographic report before skeletal scintigraphy but was identified through reevaluation or repetition of radiographs after skeletal scintigraphy. Radiographs showed sclerosis along the transverse-sacral articulation in only 8 (21%) of the 39 patients with high uptake. Findings indicating stress or motion at the joint were shown by CT in 6 (55%) of 11 and by MRI in 5 (63%) of 8 patients with high uptake at the transverse-sacral articulation who underwent these examinations.

CONCLUSION

Skeletal scintigraphy often indicates stress at the transverse-sacral articulation of young patients with low-back pain and a lumbosacral transitional vertebra. Showing evidence of stress is best accomplished using SPECT. Changes are usually not radiographically evident, but there is a trend for MRI and CT to show findings that imply stress or motion at the articulation. The unique ability of skeletal scintigraphy to provide this physiologic information supports its use in these patients.