1. Division of Spinal Surgery, Departments of Orthopaedic Surgery and Neurosurgery, NYU Medical Center, New York Spine Institute, New York, New York;
2. Department of Orthopaedic Surgery, Denver International Spine Center, Denver, Colorado;
3. Department of Orthopedics, Hospital for Special Surgery, New York, New York;
4. Department of Neurological Surgery, University of California, San Francisco, California;
5. Department of Orthopaedic Surgery, University of Kansas Medical Center, Kansas City, Kansas;
6. Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri;
7. Department of Orthopaedic Surgery, Baylor Scoliosis Center, Dallas, Texas;
8. Department of Orthopaedics, Johns Hopkins University School of Medicine, Baltimore, Maryland;
9. Department of Neurosurgery, Oregon Health & Science University, Portland, Oregon;
10. Spine Institute of Louisiana, Shreveport, Louisiana;
11. Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, Virginia; and
12. Department of Orthopaedic Surgery, University of California, Davis, California