Congenital 'butterfly vertebra' associated with low back pain: a case report.

The butterfly vertebral defect is a rare congenital anomaly of the spine, which is generally considered benign. In this report we present the case of an active young man who presented with recurrent low back pain (LBP), and was found to have a butterfly vertebral defect at the symptomatic L4 lumbar spinal level. We describe the genesis of the butterfly vertebral defect, in the context of normal embryological development of the human vertebra and intervertebral disk. We report the clinical examination findings and therapeutic interventions undertaken prior to the radiographic discovery of the vertebral defect, and discuss the impact that the presence of a butterfly vertebral defect presented to therapeutic decision-making.