1. Department of General, Visceral and Vascular Surgery , 40556 Agaplesion Bethesda Hospital Wuppertal , Wuppertal , Germany
2. Hellenic Minimally Invasive and Robotic Surgery (MIRS) Study Group, Athens Medical School , National and Kapodistrian University of Athens , Athens , Greece
3. Second Department of Propedeutic Surgery , Laiko Hospital , Athens , Greece