[1] Helsinki Univ Hosp, Abdominal Ctr, Gastroenterol Surg, Helsinki, Finland
[2] Univ Helsinki, Helsinki, Finland
[3] Oulu Univ Hosp, Dept Gastrointestinal Surg, Oulu, Finland
[4] Aalborg Univ Hosp, Dept Gastrointestinal Surg, Aalborg, Denmark
[5] Helsinki Univ Hosp, Abdominal Ctr, Gastroenterol, Helsinki, Finland
[6] Trondheim Reg & Univ Hosp, Dept Gastroenterol & Hepatol, St Olavs Hosp, Trondheim, Norway
[7] Karolinska Univ Hosp, Dept Upper Gastrointestinal Dis, Stockholm, Sweden
[8] Oslo Univ Hosp, Dept Gastroenterol, Oslo, Norway
[9] Univ Hosp, Dept Med Gastroenterol, Rikshosp, Oslo, Norway
[10] Turku Univ Hosp, Div Digest Surg & Urol, Turku, Finland
[11] Univ Turku, Turku, Finland