1Department of Orthopaedic Surgery, Northwestern University, Chicago, IL USA
2Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY USA
3Department of Orthopaedic Surgery, Rush University Medical Center, Orthopaedic Building, Suite 204-G, 1611 W Harrison Street, Chicago, IL 60612 USA
4The International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, IL USA
5Research Department, AO Spine International, Davos, Switzerland
6Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong, China
7Department of Orthopaedic and Trauma Surgery, Tampere University Hospital, Tampere, Finland
8Department of Orthopaedic and Trauma Surgery, Assiut University Medical School, Assiut, Egypt
9Department of Orthopaedics, Churruca Hospital de Buenos Aires, Buenos Aires, Argentina
10Department of Neurosurgery, John Hopkins University, Baltimore, MD USA
11Department of Orthopaedic Surgery, University of Arizona College of Medicine, Phoenix, AZ USA