1. Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada;
2. Division of Orthopedics, Department of Surgery, Shamir Medical Center (Assaf Harofeh), Zerifin, Israel;
3. Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel;
4. Institute of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada;
5. Department of Surgery, Johns Hopkins Hospital, Baltimore, Maryland, USA;
6. Division of Neurosurgery, Department of Surgery, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada;
7. Division of Neurosurgery, University of Alberta, Edmonton, Alberta, Canada;
8. Interdepartmental Division of Critical Care, University of Toronto, Toronto, Ontario, Canada;
9. Division of Neurosurgery, Department of Surgery, St. Michael's Hospital, Toronto, Ontario, Canada