[1] Univ Edinburgh, Royal Infirm, Sch Clin Sci & Community Hlth, Edinburgh, Midlothian, Scotland
[2] Ersta Hosp, Ctr Gastrointestinal Dis, S-11691 Stockholm, Sweden
[3] Huddinge Univ Hosp, Karolinska Inst, Surg Sci Ctr, S-14186 Huddinge, Sweden
[4] Univ Hosp Maastricht, Dept Surg, NL-6202 AZ Maastricht, Netherlands
[5] Univ Tromso Hosp, Dept Surg, Tromso, Norway
[6] Hvidovre Univ Hosp, Dept Surg Gastroenterol, DK-2650 Hvidovre, Denmark
[7] Rigshosp, Juliane Marie Ctr, Sect Surg Pathophysiol, DK-2100 Copenhagen, Denmark