1 Krembil Neuroscience Centre, Spinal Program, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada M5T 2S8; Department of Surgery, Division of Neurosurgery, University of Toronto, Toronto, Ontario, Canada M5T 2S8.
2 Krembil Neuroscience Centre, Spinal Program, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada M5T 2S8; Department of Surgery, Division of Neurosurgery, University of Toronto, Toronto, Ontario, Canada M5T 2S8. Electronic address: michael.fehlings@uhn.on.ca.