1. Division of Neurosurgery, University of Toronto, St. Michael's Hospital, Toronto, Ontario, Canada.
2. Institute of Clinical Evaluative Sciences, University of Toronto, St. Michael's Hospital, Toronto, Ontario, Canada.
3. Division of Neurosurgery, University of Toronto, Toronto Western Hospital, Toronto, Ontario, Canada.
4. Spinal Program, Blusson Spinal Cord Center, University of British Columbia, Vancouver, British Columbia, Canada.
5. Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada.