Joonas H Kauppila1,2. 1. Department of Surgery, Oulu University Hospital and University of Oulu, Oulu, Finland. Joonas.kauppila@oulu.fi. 2. Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden. Joonas.kauppila@oulu.fi.