1. Department of Plastic, Reconstructive and Hand Surgery, Maastricht University Medical Centre, Maastricht, the Netherlands
2. Department of Plastic, Reconstructive and Hand Surgery, Tergooi Hospital, Hilversum, the Netherlands
3. Department of General Surgery, Tergooi Hospital, Hilversum, Netherlands
4. Department of Statistics and Epidemiology, Maastricht University Medical Centre, Maastricht, the Netherlands