1. Orthopedic Pain Specialists, Santa Monica;
2. The B.A.C.K. Center, Melbourne;
3. Westlake Orthopaedics and Spine, Austin, Texas;
4. Department of Orthopaedics and Rehabilitation, University of Florida, Gainesville, Florida;
5. Tufts University School of Medicine, Boston, Massachusetts; and
6. University of Southern California, Los Angeles, California;
7. Medtronic Spine & Biologics, Memphis, Tennessee