1. Department of Surgery, School of Public Health, Collegium Medicum, University of Warmia and Mazury in Olsztyn, Poland
2. Clinical Ward of Paediatric Surgery and Urology, Regional Specialist Children's Hospital in Olsztyn, Poland
3. Department of Family Medicine and Infectious Diseases, School of Medicine, Collegium Medicum, University of Warmia and Mazury in Olsztyn, Poland