1. The Ottawa Hospital, Ottawa, Ontario, Canada
2. Winnipeg Spine Program Health Sciences Centre, University of Manitoba, Winnipeg, Manitoba, Canada
3. Division of Orthopaedic Surgery, University of Ottawa, Ottawa, Ontario, Canada
4. School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
5. Ottawa Health Research Institute, Clinical Epidemiology Program, Ottawa, Ontario, Canada
6. Research Operations, Canadian Spine Outcomes Research Network, Markdale, Ontario, Canada
7. University of Calgary, Foothills Medical Centre, Calgary, Alberta, Canada
8. Canada East Spine Center and Horizon Health Network, Dalhousie University, Saint John, New Brunswick, Canada
9. Lawson Health Research Institute/London Health Sciences Centre, Division of Orthopaedics, Department of Surgery, Western University, London, Ontario, Canada
10. Department of Surgery, Division of Neurosurgery, Dalhousie University, Halifax, Nova Scotia, Canada
11. Hôpital de l’Enfant-Jésus, Laval University, Quebec City, Quebec, Canada
12. Department of Surgery, Division of Orthopedics, Dalhousie University, Halifax, Nova Scotia, Canada
13. University of Alberta, Edmonton, Alberta, Canada
14. Department of Surgery, University of Toronto, Toronto, Ontario, Canada
15. Combined Neurosurgery and Orthopaedic Spine Program, University of British Columbia, Vancouver, British Columbia, Canada
16. Arthritis Program, Krembil Research Institute, University Health Network, Department of Surgery, Division of Orthopaedic Surgery, University of Toronto, Toronto, Ontario, Canada.