1. Section of Acute Pain Management; Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
2. Copenhagen Trial Unit, Centre for Clinical Intervention Research; Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
3. Department of Anaesthesia and Intensive Care; Helsinki University Central Hospital; Helsinki Finland
4. Department of Surgery; Herlev Hospital, University of Copenhagen; Herlev Denmark
5. Department of Anaesthesiology; Aarhus University Hospital; Aarhus Denmark
6. Department of Anaesthesiology, Centre of Head and Orthopaedics; Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
7. Pain Clinic; Helsinki University Central Hospital; Helsinki Finland
8. Department of Gynecology; Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark