[1] Orebro Univ, Fac Med & Hlth, Dept Surg, Orebro, Sweden
[2] Karolinska Inst, CLINTEC, Div Surg, Dept Surg Gastroenterol, Stockhohn, Sweden
[3] Karolinska Univ Hosp, Ctr Digest Dis, Stockholm, Sweden
[4] Mora Hosp, Dept Surg, Mora, Sweden
[5] Umea Univ, Sunderby Hosp, Div Surg, Dept Surg & Perioperat Sci, Umea, Sweden
[6] Orebro Univ, Fac Med & Hlth, Dept Surg, Lindesberg, Sweden