1. Division of Orthopedics, Rady Children’s Hospital-San Diego, 3020 Children’s Way, MC 5054, San Diego, CA 92123, USA
2. Department of Orthopaedic Surgery, University of California San Diego, San Diego, CA 92103, USA
3. Department of Pathology, Rady Children’s Hospital San Diego, San Diego, CA 92123, USA
4. Department of Orthopaedic Surgery, Chonbuk National University Hospital, Jeonbuk 561-712, Republic of Korea
5. San Diego Center for Spinal Disorders, La Jolla, CA 92037, USA