1. Department of General, Visceral and Transplantation Surgery, Heidelberg University Hospital, 69120 Heidelberg, Germany
2. Study Center of the German Society of Surgery, 69120 Heidelberg, Germany
3. Department of Surgery, Cantonal Hospital Thurgau, 8596 Münsterlingen, Switzerland
4. Department of Surgery, Cantonal Hospital Thurgau, 8501 Frauenfeld, Switzerland