1. Pain Treatment Centers of America, Little Rock, AR, USA
2. Ohio University – HCOM, OH, USA
3. Adena Spine Center, Chillicothe, OH, USA
4. Department of Physical Medicine and Rehabilitation, University of Kentucky, Lexington, KY, USA
5. Division of Pain Medicine, Department of Anesthesiology, University of Calgary, Calgary, AB, Canada
6. Spine and Nerve Center of the Virginias, Charleston, WV, USA