1. Department of General, Visceral, Vascular and Pediatric Surgery, Saarland University, Saarland University Medical Center, Homburg, Germany
2. Department of Surgery, University Hospital Knappschaftskrankenhaus Bochum, Ruhr-University Bochum, Bochum, Germany
3. Department of Surgery, Laiko General Hospital, National and Kapodistrian University of Athens, Athens, Greece