1. Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania;
2. Division of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania;
3. Neurological Surgery, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania;
4. Department of Neurological Surgery, University of California, San Francisco, California;
5. Department of Neurosurgery, Columbia University Irving Medical Center, New York, New York;
6. Department of Neurological Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin;
7. Department of Neurosurgery, Semmes Murphey Clinic, Memphis, Tennessee;
8. Department of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona;
9. Department of Orthopedic Surgery, Scripps Clinic, La Jolla, California;
10. Department of Neurological Surgery, Rush University Medical Center, Chicago, Illinois;
11. Department of Neurosurgery, Weill Cornell Medical Center, New York, New York;
12. Department of Neurosurgery, University of Miami, Florida;
13. Division of Neurosurgery, Hoag Neurosciences Institute, Newport Beach, California;
14. Spine Institute of Louisiana, Shreveport, Louisiana;
15. Department of Orthopaedics, Cedars-Sinai Medical Center, Los Angeles, California;
16. Department of Orthopaedic Surgery, NYU Langone Orthopedic Hospital, New York, New York;
17. Denver International Spine Center, Presbyterian St. Luke’s/Rocky Mountain Hospital for Children, Denver, Colorado; and
18. Department of Neurosurgery, Duke University, Durham, North Carolina