1. Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
2. Division of Neurosurgery, Spinal Program, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
3. Division of Orthopedics, Department of Surgery, University of Toronto, Toronto, Ontario, Canada; and
4. Division of Neuroradiology, Department of Medical Imaging, Toronto Western Hospital, Toronto, Ontario, Canada