[1] Univ Milan, IRCCS Osped Galeazzi St Ambrogio, Dept Biomed Sci Hlth, Div Gen Surg, Milan, Italy
[2] IRCCS Humanitas Res Hosp, Upper Gastrointestinal Surg Unit, Milan, Italy
[3] Clin Northwest, Dept Bariatr & Metab Med, Frankfurt, Germany
[4] Univ Oxford, Nuffield Dept Surg Sci, Oxford, England
[5] Univ Milan, Dept Biomed Sci Hlth, Div Gen & Foregut Surg, IRCCS Policlin San Donato, Milan, Italy