1. First Department of Surgery, Laikon General Hospital, National and Kapodistrian University of Athens, Athens, Greece
2. Clinic for General, Visceral and Transplant Surgery, University Clinic Essen, Essen, Germany
3. Fourth Department of Surgery, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
4. First Propedeutic Department of Surgery, Hippocration General Hospital, National and Kapodistrian University of Athens, Athens, Greece