[1] Thomas Jefferson Univ, Dept Orthopaed Surg, Rothman Inst, Philadelphia, PA 19107 USA
[2] BG Unfallklin Frankfurt Main, Ctr Spine Surg & Neurotraumatol, Frankfurt, Germany
[3] Catholic Univ Parana, Cajuru Hosp, Spine Surg Grp, Dept Orthoped, Curitiba, Parana, Brazil
[4] Univ Med Ctr Utrecht, Dept Orthopaed, Utrecht, Netherlands
[5] Univ Toronto, Dept Surg, Div Neurosurg, Toronto, ON, Canada
[6] Univ Toronto, Inst Med Sci, Toronto, ON, Canada
[7] Univ Toronto, UHN, McEwen Ctr Regenerat Med, Toronto, ON, Canada
[8] Univ Toronto, Spine Program, Toronto, ON, Canada
[9] Univ Toronto, McLaughlin Ctr Mol Med, Toronto, ON, Canada
[10] Toronto Western Hosp, Genet & Dev, Krembil Discovery Tower, Toronto, ON, Canada