1. aDepartment of Special Anaesthesia and Pain Therapy, Medizinische Universität/AKH Wien, Vienna, Austria
2. bHampshire Hospitals NHS Trust, Winchester, Hants, UK
3. cUniversitätsspital Zurich, Zurich, Switzerland
4. dSanta Maria General Hospital, Terni, Italy
5. eUniversity Hospitals of Leicester NHS Trust, Leicester, UK
6. fDepartment of Medical and Surgical Sciences and Biotechnologies, Sapienza University of Rome, Italy
7. gUniversity Hospital, Rotterdam, The Netherlands
8. hWilhelminenspital der Stadt Wien, Austria
9. iPain Clinic, Department of Anaesthesiology, Intensive Care and Pain Medicine, University of Helsinki, and Helsinki University Hospital, Finland
10. jDepartment of Pain Research and Treatment, Collegium Medicum Jagiellonian University, Kraków, Poland
11. kUNIDOR, Centro Hospitalar de Leiria, Leiria, Portugal
12. lHospital General Universitario de Alicante, Spain
13. mClinique Cecil, Lausanne, Switzerland
14. nUniversity Hospitals Leuven, Belgium
15. oSchmerz- und Palliativzentrum, Göppingen, Germany
16. pSt. Georges Hospital, London, UK
17. qHospital Universitario de la Princesa, Madrid, Spain
18. rHôpitaux de Saint-Denis, Paris, France