[1] Department of Surgery and Perioperative Science, Umeå University, Umeå
[2] Department of Surgery, Helsingborg Hospital, Helsingborg
[3] Department of Surgery, University Hospital of Malmö, Malmö
[4] Department of Surgery, Östersund Hospital, Östersund
[5] Department of Surgery, Karlstad Hospital, Karlstad
[6] Kirugkliniken, Sundsvalls Sjukhus