[1] NYU Langone Med Ctr, Dept Neurol, New York, NY USA
[2] Univ British Columbia, Dept Orthopaed, Vancouver, BC, Canada
[3] Univ British Columbia, Int Collaborat Repair Discoveries ICORD, Vancouver, BC, Canada
[4] Univ Calgary, McCaig Inst Bone & Joint Hlth, Cumming Sch Med, Dept Surg,Orthopaed Surg, Calgary, AB, Canada
[5] Univ Toronto, Inst Med Sci, Toronto, ON, Canada
[6] Aggregate Analyt Inc, Fircrest, WA USA
[7] Univ Toronto, Dept Surg, Div Neurosurg, Toronto, ON, Canada
[8] Univ Toronto, Dept Surg, Spine Program, Toronto, ON, Canada
[9] Univ Hlth Network, Toronto Western Hosp, Krembil Neurosci Ctr, Div Neurosurg, 99 Bathurst St,Suite 4WW-449, Toronto M5T 2S8, ON, Canada