[1] Johns Hopkins Sch Med, Dept Anesthesiol, Pain Med Div, Baltimore, MD 21205 USA
[2] Johns Hopkins Sch Med, Dept Anesthesiol, Pain Med Div, Baltimore, MD USA
[3] Carolinas Pain Inst, Winston Salem, NC USA
[4] Univ Virginia, Dept Anesthesia, Divs Pain Med, Charlottesville, VA USA
[5] Premier Pain Ctr, Shrewsbury, NJ USA
[6] Wake Forest Univ Bowman Gray Sch Med, Winston Salem, NC USA
[7] NSPC Millennium Pain Ctr, Bloomington, IL USA
[8] Ochsner Clin Fdn, New Orleans, LA USA
[9] Brigham & Womens Hosp, Boston, MA USA
[10] Clin Invest LLC, Edmond, OK USA
[11] Int Spine Pain & Performance Ctr, Washington, DC USA