1. Department of Otolaryngology, Medical University of Bialystok, Bialystok, Poland
2. 1st Department of General and Endocrinological Surgery, Medical University of Bialystok, Bialystok, Poland
3. Department of General and Minimally Invasive Surgery, Municipal Polyclinical Hospital, Olsztyn, Poland
4. Department of Statistics and Medical Informatics, Medical University of Bialystok, Bialystok, Poland
5. Department of Endocrine Surgery, Third Chair of General Surgery, Jagiellonian University, Medical College, Krakow, Poland