1. Institute of Quality Assurance in Operative Medicine (IQOM), Otto von Guericke University , Magdeburg , Germany
2. Department of General and Abdominal Surgery , Municipal Hospital (Klinikum Magdeburg GmbH) , Magdeburg , Germany
3. Department of General, Abdominal, Vascular and Transplant Surgery , Otto von Guericke University with University Hospital , Magdeburg , Germany