[1] Washington Univ, Sch Med, Dept Anesthesiol, Div Clin & Translat Res, St Louis, MO 63110 USA
[2] Aarhus Univ Hosp, Danish Pain Res Ctr, DK-8000 Aarhus, Denmark
[3] Aarhus Univ Hosp, Dept Anesthesiol, DK-8000 Aarhus, Denmark
[4] Aarhus Univ Hosp, Dept Neurol, DK-8000 Aarhus, Denmark