1 Department of Surgery and Center for Minimally Invasive Surgery, Academic Teaching Hospital of Charité Medical School, Vivantes Hospital, Neue Bergstrasse 6, 13585, Berlin, Germany. ferdinand.koeckerling@vivantes.de.
2 Department of General Surgery, Country Hospital Hochsteiermark, Steiermärkische Krankenanstaltengesellschaft m.b.H, Tragösserstrasse 1 and 1a, 8600, Bruck/Mur, Austria.
3 StatConsult GmbH, Halberstädter Strasse 40 a, 39112, Magdeburg, Germany.
4 Department of General, Visceral and Oncological Surgery, Wilhelminenspital, 1160, Vienna, Austria.
5 Medical Faculty Sigmund-Freud-Faculty, Freudplatz 1, 1120, Vienna, Austria.