Bilateral retrosomatic clefts at multiple lumbar levels.

Low back pain developed in a 44-year-old woman with a history of rheumatoid arthritis. Radiographs of the lumbar spine revealed bilateral pedicle defects at L-3, L-4, and L-5, with widening of the spinal canal and spondylolisthesis of L-5 on S-1. CT more clearly demonstrated bilateral retrosomatic clefts at multiple levels.