1. Department of Orthopedic Surgery, Washington University School of Medicine, Saint Louis, Missouri;
2. Department of Orthopedic Surgery, Hospital for Special Surgery, New York, New York;
3. Department of Neurological Surgery, Johns Hopkins University, School of Medicine, Baltimore, Maryland;
4. Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia;
5. Rocky Mountain Hospital for Children, Denver, Colorado;
6. Department of Orthopedic Surgery, University of California, Davis, Sacramento;
7. San Diego Center for Spinal Disorders, La Jolla, California;
8. Department of Orthopedic Surgery, University of Kansas Medical Center, Kansas City, Kansas;
9. Department of Orthopedic Surgery, Oregon Health & Science University, Portland, Oregon;
10. Department of Surgery, University of Calgary, School of Medicine, Calgary, Alberta, Canada; and
11. Department of Orthopedic Surgery, New York University, School of Medicine, New York, New York.