1. Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
2. Division of Neurosurgery, Krembil Neuroscience Center, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada.
3. Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
4. Neuroscience Research Australia and Prince of Wales Hospital, Sydney, New South Wales, Australia.
5. Royal North Shore Hospital, St. Leonards, New South Wales, Australia.
6. Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA.
7. Center for Orthopedic and Trauma Research, Adelaide Medical School, the University of Adelaide, Adelaide, South Australia, Australia.
8. Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Champaign, Illinois, USA.
9. Department of Neurosurgery and the Miami Project to Cure Paralysis, the Miller School of Medicine, University of Miami, Miami, Florida, USA.
10. Department of Neurosurgery, Medical College of Wisconsin, Wauwatosa, Wisconsin, USA.
11. Department of Neurosurgery, Pennsylvania Hospital, University of Pennsylvania Health System, Philadelphia, Pennsylvania, USA.
12. Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
13. Department of Neurosurgery, Health Science Center, University of Texas, Houston, Texas, USA.
14. Department of Orthopedics, University of Utah, Salt Lake City, Utah, USA.
15. Department of Neurological Surgery, Emory University School of Medicine, Atlanta, Georgia, USA.
16. Department of Neurosurgery, Washington University, St. Louis, Missouri, USA.
17. Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
18. Department of Neurosurgery and School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.
19. Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas, USA.
20. Department of Neurosurgery, Houston Methodist Hospital, Houston, Texas, USA.
21. Department of Health Services, University of Washington, Seattle, Washington, USA.