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