[1] Ziekenhuis Oost Limburg, Intens Care Emergency Med & Multidisciplinary Pain, Dept Anesthesiol, Genk Lanaken, Limburg, Belgium
[2] Johns Hopkins Sch Med, Pain Med Div, Dept Anesthesiol, Baltimore, MD USA
[3] Rijnstate Ziekenhuis, Dept Anesthesiol & Pain Med, Velp, Netherlands
[4] Amsterdam Univ Med Ctr, Anesthesiol & Pain Med, Amsterdam, Netherlands
[5] Univ Groningen, UMCG Pain Ctr Groningen, Dept Anesthesiol, Groningen, Netherlands
[6] Erasmusmc, Dept Anesthesiol & Pain Med, Rotterdam, Netherlands
[7] Univ Med Ctr Utrecht, Dept Anesthesiol & Pain Med, Utrecht, Netherlands
[8] Catharina Hosp, Anesthesiol & Pain Med, Eindhoven, Netherlands
[9] Radboud Univ Nijmegen, Dept Anesthesiol Pain & Palliat Med, Nijmegen, Netherlands
[10] Brigham & Womens Spine Ctr, Dept Anesthesiol & Pain Med, Boston, MA USA
[11] Maastricht Univ, Med Ctr, Dept Anesthesiol & Pain Med, Maastricht, Netherlands
[12] Ziekenhuis Oost Limburg, Intens Care Emergency Med & Multidisciplinary Pain, Dept Anesthesiol, Bessemersstr 478, B-3620 Genk Lanaken, Belgium