1. Pain Center; AZ Sint Jan; Brugge Belgium
2. Pain Relief Unit; Medical Center Alkmaar and Slotervaartziekenhuis; Amsterdam The Netherlands
3. Multidisciplinary Pain Center; Ziekenhuis Oost-Limburg; Genk Belgium
4. Department of Pain Management; Case Western Reserve University Hospitals; Cleveland Ohio U.S.A
5. Department of Pain Management; Cleveland Clinic; Cleveland Ohio U.S.A