[1] Rehabil Inst Chicago, Ctr Pain Studies, Chicago, IL 60611 USA
[2] Louisiana State Univ, Sch Med, Dept Anesthesia, New Orleans, LA USA
[3] Louisiana State Univ, Sch Med, Dept Anesthesiol & Pharmacol, New Orleans, LA USA
[4] Lutheran Med Grp, Ft Wayne, IN USA
[5] Albany Med Ctr, AMC Neurol Grp, Albany, NY USA