1. 1Neuro-Spine Program, Division of Pediatric Neurosurgery, Texas Children's Hospital, and Department of Neurosurgery, Baylor College of Medicine, Houston, Texas;
2. 2Division of Pediatric Neurosurgery, Akron Children's Hospital, Akron, Ohio; and
3. 3Division of Spinal Surgery, Department of Neurological Surgery, University of Wisconsin, Madison, Wisconsin