1. Division of Physical Medicine and Rehabilitation, University of Utah, Salt Lake City, Utah, USA
2. Center for Pain Medicine, Department of Anesthesiology, University of California, San Diego, La Jolla, California, USA
3. Department of Neurological Surgery, University of Southern California, Los Angeles, California, USA
4. University of California, Los Angeles David Geffen School of Medicine, Los Angeles, California, USA
5. Department of Orthopaedic Surgery, Emory University, Atlanta, Georgia
6. Department of Physical Medicine and Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
7. Spine Intervention Society, Hinsdale, Illinois, USA