Limbus vertebra



Illustration 1.

The patient, a 38-year-old woman with a 4-month history of low back pain, was referred to our care. She had no symptoms suggestive of inflammatory back pain, and results of the physical examination, including results of neurologic tests, were within normal ranges. Findings of motor and sensory conduction studies were also noted to be normal. Sagittal computed tomography scanning of her lumbar spine revealed well-corticated, triangular bone fragments on anterior and superior end plates of multiple vertebrae, a finding that is compatible with limbus vertebra. Limbus vertebra is a defect that usually occurs at the superior anterior margin of the lumbar vertebrae. The inferior and posterior margin and other regions of the spine are less frequently affected. Limbus vertebra is a consequence of a remote injury in an immature skeleton, thought to result from herniation of the nucleus pulposus through the ring apophysis prior to fusion, separating a small segment from the vertebral rim. While most reported cases of limbus vertebra have consisted of solitary involvement, to our knowledge, no formal study has addressed the prevalence of either solitary or multiple limbus vertebrae. Whereas anterior limbus vertebra is believed to be asymptomatic, posterior limbus vertebra has been reported to cause nerve compression. Limbus vertebra could be mistaken for a fracture, discitis, Schmorl's node, or tumor, resulting in unnecessary, even invasive, diagnostic procedures. This is most likely to occur when a patient presents with back pain, especially after trauma. Limbus vertebra is an incidental finding and typically not the cause of the pain; thus, it needs no medication or treatment. It is important to consider this defect in differential diagnosis.