1. Institute of Applied Health Sciences, Epidemiology group, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, department of Anaesthesia, NHS Grampian, Aberdeen, UK
2. Anesthesiology and Perioperative Medicine, Acute and Chronic Pain Therapy, Vrije Universiteit Brussel (VUB), Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium