1. Alan and Jacqueline Stuart Spine Center, Department of Neurosurgery, Lahey Hospital and Medical Center, Burlington, Massachusetts
2. Tufts University School of Medicine, Boston, Massachusetts
3. Wallace Trials Center, Greenwich Hospital, Greenwich, Connecticut
4. Center for Spine Health and Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, Ohio
5. Department of Neurosurgery, Rutgers, State University of New Jersey--New Jersey Medical School, Newark, New Jersey
6. Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri
7. Department of Orthopedic Surgery, Thomas Jefferson University and Rothman Institute, Philadelphia, Pennsylvania
8. Neurosurgical Service, Massachusetts General Hospital, and Department of Surgery, Harvard Medical School, Boston, Massachusetts
9. Department of Orthopedic Surgery, Emory Spine Center, Atlanta, Georgia
10. Department of Neurological Surgery, Neurological Institute of New York, Columbia University Medical Center, New York, New York
11. Institute for Clinical Research and Health Policy Studies, Tufts Medical Center and Tuft University School of Medicine, Boston, Massachusetts
12. Perelman School of Medicine, Wharton School of Business and Leonard Davis Institute, University of Pennsylvania, Philadelphia, Pennsylvania