1. Schmerz- und Palliativzentrum, Göppingen, Germany;
2. University Hospitals Leuven, Belgium;
3. Capio St Görans Hospital, Stockholm, Sweden;
4. Universitätsspital Zurich, Zurich, Switzerland;
5. Santa Maria General Hospital, Terni, Italy;
6. Department of Medical and Surgical Sciences and Biotechnologies, Sapienza University of Rome, Italy;
7. University Hospital, Rotterdam, The Netherlands;
8. Wilhelminenspital der Stadt Wien, Austria;
9. Pain Clinic, Department of Anaesthesiology, Intensive Care and Pain Medicine, University of Helsinki, and Helsinki University Hospital, Finland;
10. Department of Pain Research and Treatment, Collegium Medicum Jagiellonian University, Kraków, Poland;
11. Department of Special Anaesthesia and Pain Therapy, Medizinische Universität/AKH Wien, Vienna, Austria;
12. Hospital de Santo André, Leiria, Portugal;
13. Hospital General Universitario de Alicante, Spain;
14. Clinique Cecil, Lausanne, Switzerland;
15. St. Georges Hospital, London, UK;
16. Hospital Universitario de la Princesa, Madrid, Spain;
17. Naples Anesthesia and Pain Associates, Naples, FL, USA;
18. Department of Anaesthesiology and Intensive Care Medicine, Charité University Berlin, Campus Virchow Klinikum, Berlin, Germany;
19. Hôpitaux de Saint-Denis, Paris, France