1. Division of Neurosurgery, Department of Surgery, 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
4. Department of Orthopaedic Surgery, Rothman Orthopaedic Institute, Thomas Jefferson University, Philadelphia, Pennsylvania
5. Department of Neurosurgery, University of Maryland School of Medicine, Baltimore
6. Department of Medical Imaging, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
7. Division of Neurosurgery, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada