1. Department of Visceral, Transplant, Thoracic and Vascular Surgery , University Hospital of Leipzig , Leipzig , Germany
2. Department of General, Visceral and Transplant Surgery , University Hospital of Münster , Münster , Germany
3. Innovation Center Computer Assisted Surgery, University of Leipzig , Leipzig , Germany
4. Department of General, Visceral and Vascular-Surgery , St. George’s Hospital of Leipzig , Leipzig , Germany