[1] Ersta Hosp, Dept Surg, Stockholm, Sweden
[2] Karolinska Inst, Dept Clin Sci, Danderyd Hosp, Stockholm, Sweden
[3] Royal Surrey Cty Hosp NHS Fdn Trust, Dept Anaesthesia & Intens Care Med, Guildford, Surrey, England
[4] Univ Surrey, Fac Hlth & Med Sci, Guildford GU2 5XH, Surrey, England
[5] Asklepios Klin Altona, Dept Gen & Visceral Surg, Ctr Minimalinvas & Oncol Surg, Hamburg, Germany
[6] Univ Hosp CHUV, Dept Visceral Surg, Lausanne, Switzerland
[7] Scarborough Gen Hosp, Dept Surg, Scarborough, N Yorkshire, England
[8] McGill Univ, Dept Surg, Montreal, PQ H3A 2T5, Canada
[9] Univ Auckland, Dept Surg, Auckland 1, New Zealand
[10] Univ Auckland, Dept Surg, S Auckland Clin Sch, Middlemore Hosp, Auckland 1, New Zealand
[11] NW London Hosp NHS Trust, St Marks Hosp, Harrow, Middx, England
[12] Univ Nottingham Hosp, Queens Med Ctr, Div Gastrointestinal Surg, Nottingham Digest Dis Ctr Natl Inst Hlth Res Biom, Nottingham NG7 2UH, England
[13] Univ Edinburgh, Edinburgh, Midlothian, Scotland
[14] Univ Orebro, Dept Surg, Orebro, Sweden
[15] Univ Hosp, Orebro, Sweden
[16] Karolinska Inst, Inst Mol Med & Surg, Stockholm, Sweden