1. Michigan State University College of Human Medicine, Flint, Michigan, USA.
2. Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD, USA.
3. Wayne State University School of Medicine, Detroit, Michigan, USA.
4. Stanford University School of Medicine, Stanford, California, USA.
5. University of Texas Southwestern Medical Center, Dallas, Texas, USA.
6. Duke University School of Medicine, Durham, North Carolina, USA.
7. Texas Back Institute, Plano, Texas, USA.
8. Boston Children's Hospital, Boston, Massachusetts, USA.
9. Memorial Hermann Health System, Houston, Texas, USA.
10. Meharry Medical College, Nashville, Tennessee, USA.
11. Lone Star Orthopedic Institute, Kingwood, Texas, USA.
12. Health First, Melbourne, Florida, USA.