1. Division of Neurosurgery, Department of Surgery, Management, and Evaluation, University of Toronto, Toronto, Ontario, Canada.
2. Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Ontario, Canada.
3. Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
4. Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
5. Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA.
6. Independent Consultant, Chicago, Illinois, USA.