1. Department of Surgery, Odessa National Medical University , Odessa , Ukraine
2. Faculty of Medicine, Vilnius University , Vilnius , Lithuania
3. Department of Surgery, Klaipeda University Hospital , Klaipeda , Lithuania
4. Department of Surgery, Klaipeda University , Klaipeda , Lithuania
5. SMK, University of Applied Social Sciences , VIlnius , Lithuania
6. Department of General and Abdominal Surgery and Oncology, National Cancer Institute , Vilnius , Lithuania