[1] Toronto Western Res Inst, Univ Hlth Network, Dept Genet & Dev, Toronto, ON M5T 2S8, Canada
[2] Univ Toronto, Toronto Rehabil Inst, Lyndhurst Ctr, Toronto, ON, Canada
[3] Toronto Western Res Inst, Univ Hlth Network, Spinal Program, Krembil Neurosci Ctr, Toronto, ON M5T 2S8, Canada
[4] Univ Toronto, Dept Surg, Div Neurosurg, Toronto, ON, Canada
[5] Univ Toronto, Spinal Program, Toronto, ON, Canada