aSpine Care Institute, Hospital for Special Surgery, Weill Cornell Medicine, New York, NY

bDepartment of Spine Surgery, Lucerne Cantonal Hospital, Lucerne, Switzerland

cDepartment of Orthopedic Surgery, Showa University School of Medicine, Tokyo, Japan

dWeill Cornell Medical College, New York, NY

eDepartment of Orthopedic Surgery and Traumatology, Medical University of Vienna, Vienna, Austria

fMarc A. Asher, MD, Comprehensive Spine Center, University of Kansas Medical Center, Kansas City, KS

gCenter for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany

hDepartment of Orthopedic Surgery and Traumatology, University Hospital Düsseldorf, Düsseldorf, Germany

iDepartment of Radiology and Imaging, Hospital for Special Surgery, Weill Cornell Medicine, New York, NY

IRB-approval: Hospital for Special Surgery (#2016-0751).

M.M., I.O., E.T.T., J.S., A.A.S., F.P.C., F.P.G., and A.P.H.: conception design. M.M., I.O., L.A.S., S.N.S., B.B.C., D.A.A., L.O., and E.C.: acquisition of data. M.M. and I.O.: analysis and interpretation of data. M.M.: drafting the article. A.P.H.: approved the final version of the manuscript on behalf of all authors. I.O.: statistical analysis. M.M., E.T.T., and J.S.: administrative/technical/material support. A.P.H. study supervision.

The authors report no conflicts of interest.

Address correspondence and reprint requests to Alexander P. Hughes, MD, Spine Care Institute, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021; E-mail: [email protected]

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