1. Department of Orthopaedic Surgery, University of California, Los Angeles, California, United States
2. Department of Orthopaedic Surgery, Nanjing Medical University, Nanjing Hospital, Nanjing, China
3. Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, United States
4. Department of Orthopaedic Surgery, Uijongbu St. Mary's Hospital, The Catholic University of Korea School of Medicine, Uijongbu, Korea
5. Department of Orthopedics, University of Utah School of Medicine, Salt Lake City, Utah, United States
6. Department of Neurosurgery, Bergmannstrost Hospital, Halle, Germany
7. Durango Orthopedic Associates, P.C./Spine Colorado, Durango, Colorado, United States
8. Department of Orthopedics, Emory Spine Center, Atlanta, Georgia