1. Department of Anesthesiology & Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
2. The Pain Management Center, 2271 NJ-33 #103, Hamilton Township, NJ 08690, USA
3. Department of Neurosurgery, Warren Alpert Medical School, Brown University, 593 Eddy Street, George 1st Floor, Providence, RI 02903, USA
4. Department of Anesthesiology, University of Pittsburgh School of Medicine, 3471 Fifth Avenue, Suite 402, Pittsburgh, PA 15213, USA
5. The Spine & Nerve Center of The Virginias, 400 Court Street, Suite 100, Charleston, WV 25301, USA