[1] Oslo Univ Hosp, Intervent Ctr, Postbox 4950 Nydalen, N-0424 Oslo, Norway
[2] Oslo Univ Hosp, Dept Hepatopancreatobiliary Surg, Oslo, Norway
[3] Oslo Univ Hosp, Dept Tumour Biol, Oslo, Norway
[4] Oslo Univ Hosp, Dept Gastroenterol Surg, Oslo, Norway
[5] Oslo Univ Hosp, Dept Informat Technol, Oslo, Norway
[6] Oslo Univ Hosp, Dept Transplantat Med, Oslo, Norway
[7] Oslo Univ Hosp, Oslo Ctr Biostat & Epidemiol, Res Support Serv, Oslo, Norway
[8] Univ Oslo, Inst Clin Med, Oslo, Norway
[9] Univ Oslo, Inst Hlth Management & Hlth Econ, Oslo, Norway
[10] Univ Oslo, Inst Hlth & Soc, Oslo, Norway
[11] Fonna Hosp Trust, Dept Surg, Stord, Norway
[12] Haukeland Hosp, Dept Gastrointestinal Surg, Bergen, Norway
[13] IM Sechenov First Moscow State Med Univ, Dept Fac Surg 2, Moscow, Russia
[14] Yerevan State Med Univ M Heratsi, Dept Surg 1, Yerevan, Armenia