1. Institution for Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm, Sweden;
2. Department of Surgery at Centre for Digestive Diseases, Karolinska University Hospital, Stockholm, Sweden;
3. Department of Surgery and Clinical and Experimental Medicine, County council of Ostergotland, Linköping University Hospital, Linköping, Sweden;
4. Sahlgrenska University Hospital, Gothenborg, Sweden;
5. Skånes University Hospital, Lund, Sweden;
6. Norrlands University Hospital, Umeå, Sweden;
7. Uppsala University Hospital, Uppsala, Sweden