Butterfly vertebra with lumbar intervertebral disc herniation.

A butterfly vertebra is a rare congenital anomaly that is usually asymptomatic. The authors, however, describe a novel case involving a butterfly vertebra overlapping with disc herniation that presented as radiculopathy. A butterfly vertebra is characterized by a symmetrical fusion defect resulting in a sagittal cleft vertebra. Only a few cases of butterfly vertebrae have been reported as incidental findings. This spinal anomaly may be associated with other congenital conditions such as Pfeiffer, Crouzon, Jarcho-Levin, and Alagille syndromes. Moreover, there is no previous report of a case associated with symptomatic disc herniation from the sagittal cleft. The authors excised the herniated disc fragment. They performed intraoperative discography after exposure of the corresponding intervertebral space via a conventional interlaminar approach. Histological examination of a tissue specimen showed scattered chondrocytes in the myxohyaline stroma, which indicated the nucleus pulposus.