1. Radboud University Medical Center , Faculty of Medicine , Regenwulp 19 Breda , 4822 RJ , the Netherlands
2. Radboud University Medical Center , Department of Anaesthesiology , Pain and Palliative Medicine , Nijmegen , the Netherlands
3. University of Ljubljana , Faculty of Medicine , Department of Family Medicine , Poljanski nasip 58, 1000 Ljubljana , Slovenia