1. Pain Clinic; Department of Anaesthesiology; Parc de Salut MAR; Fundació IMIM; Neurosciences Programme; Perioperative Medicine Research Group; Universitat Autònoma de Barcelona; Barcelona Spain
2. Anaesthesia Department and Pain Clinic; Hospital Universitario Son Llatzer; Palma de Mallorca Spain
3. Acute Pain Service; Hospital General Gregorio Marañón; Madrid Spain
4. Department of Anaesthesiology; Hospital Nuestra Señora de Valme; Sevilla Spain
5. Pain Clinic; Department of Anaesthesiology; Hospital General Universitario de Alicante; Alicante Spain