1. Scientific Institute for Quality of Healthcare, Nijmegen, The Netherlands
2. Department of Gastroenterology and Hepatology, Radboud University Medical Centre, Nijmegen, The Netherlands
3. Department of Surgery, Radboud University Medical Centre, Nijmegen, The Netherlands
4. Department of Medical and Clinical Psychology, Centre of Research on Psychology in Somatic diseases (CoRPS), Tilburg University, Tilburg, The Netherlands
5. Department of Surgery, Medisch Spectrum Twente Hospital, Enschede, The Netherlands
6. Department of Surgery, St Elisabeth Hospital, Tilburg, The Netherlands