1. Department of General and Visceral Surgery, St. Josef-Hospital, Ruhr-Universität Bochum , Bochum , Germany
2. Faculty of Medicine, Ruhr-Universität Bochum , Bochum , Germany
3. StuDoQ Registry, German Society for General and Visceral Surgery , Berlin , Germany
4. Surgical Department, Universitätsklinikum Schleswig-Holstein Campus Lübeck , Lübeck , Germany
5. Department of General, Visceral, Transplant, Vascular and Thoracic Surgery, Klinikum Großhadern, Ludwig-Maximilians-Universität München , München , Germany
6. Department of General and Visceral Surgery, Endocrine Surgery und Coloproctology, Klinikum Neuperlach, Städt. Klinikum München , München , Germany
7. Department of Visceral, Thoracic and Vascular Surgery, Universitätsklinikum Marburg , Marburg , Germany
8. Department of General, Visceral, Vascular and Pediatric Surgery, Universitätsklinik Würzburg , Würzburg , Germany
9. Department of Surgery, Klinikum rechts der Isar, Technische Universität München , München , Germany
10. Department of General, Visceral and Transplant Surgery, Westpfalz-Klinikum Kaiserslautern , Kaiserslautern , Germany
11. Department of Surgery, Asklepios Klinik Barmbek , Barmbek , Germany
12. Department of Visceral, Colorectal Surgery and Proctology, Universitätsklinikum Bonn , Bonn , Germany