Fractures of Lumbar Ring Apophysis

Fracture of the posterior lumbar ring apophysis or vertebral cartilaginous end plate is unusual, having previously been described only in adolescent males. In this report, we present 3 such cases involving 2 adolescent males and 1 adolescent female. All patients had a bony ridge or fragment projecting into the spinal canal, usually from the lower border of L4 vertebral body; a defect in the posteroinferior aspect of the vertebral body. Preoperative myelogram and computerized tomogram including plain X-ray appear to be helpful in demonstrating bone within the canal and preoperative diagnosis can facilitate selection of the appropriate surgical approach. The radiographic findings, including the myelogram and computerized tomographic appearance are detailed and the previous literatures are reviewed.