[1] Weill Cornell Med, Hosp Special Surg, Spine Care Inst, 535 E 70th St, New York, NY 10021 USA
[2] Charite Univ Med Berlin, Ctr Musculoskeletal Surg, Berlin, Germany
[3] Free Univ Berlin, Berlin, Germany
[4] Humboldt Univ, Berlin, Germany
[5] Showa Univ Hosp, Sch Med, Dept Orthopaed Surg, Tokyo, Japan
[6] Univ Ulm, Dept Orthopaed Surg, Ulm, Germany
[7] Hosp Special Surg, Biostat Core, New York, NY USA
[8] Univ Buenos Aires, Sch Med, Normal Anat Dept 3, Buenos Aires, Argentina
[9] Hosp Italiano Buenos Aires, Pediat Neurol Dept, Intraoperat Monitoring, Buenos Aires, Argentina