[1] Med Coll Wisconsin, Dept Neurosurg, Milwaukee, WI 53226 USA
[2] Marquette Univ, Dept Phys Therapy, Milwaukee, WI 53233 USA
[3] Univ Hlth Network, KITE Res Inst, Toronto, ON, Canada
[4] Univ Toronto, Dept Med, Div Phys Med & Rehabil, Toronto, ON, Canada
[5] Balgrist Univ Hosp, Univ Spine Ctr, Zurich, Switzerland
[6] Univ British Columbia, Vancouver Spine Surg Inst, Dept Orthoped, Vancouver, BC, Canada
[7] Univ Toronto, Dept Surg, Div Neurosurg, Toronto, ON, Canada
[8] Thomas Jefferson Univ, Dept Neurol Surg, Philadelphia, PA 19107 USA
[9] Univ Maryland, Sch Med, Dept Neurosurg, Baltimore, MD 21201 USA
[10] Univ Tehran Med Sci, Sina Trauma & Surg Res Ctr, Dept Neurosurg, Tehran, Iran
[11] Univ Miami, Miller Sch Med, Dept Neurosurg, Miami, FL 33136 USA
[12] Univ Miami, Miller Sch Med, Miami Project Cure Paralysis, Miami, FL 33136 USA
[13] Univ Cambridge, Dept Neurosurg, Cambridge, England
[14] Univ Hong Kong, Li Ka Shing Fac Med, Dept Orthopaed & Traumatol, Hong Kong, Peoples R China