1. Department of Orthopaedic Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois
2. Department of Orthopaedic Surgery, UCLA Comprehensive Spine Center, Santa Monica, California
3. University of Connecticut Medical Center, Farmington, Connecticut
4. Rush University Medical Center, Chicago, Illinois
5. Emory Spine Center, Atlanta, Georgia
6. Durango Orthopedic Associates, PC/Spine Colorado
7. University of Utah, Salt Lake City, Utah
8. Resources for Medical Education and Collaboration, Durango, Colorado