1. Department of Otolaryngology, Head and Neck Surgery, Medical University, Borowska 213, 50-556 Wroclaw, Poland
2. Department of Cryogenics and Aerospace Engineering, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
3. Statistical Analysis Centre, Wroclaw Medical University, 50-368 Wroclaw, Poland
4. Maxillofacial Surgery Ward, EMC Hospital, Pilczycka 144, 54-144 Wroclaw, Poland
5. Health Department, Academy of Applied Sciences, Academy of Silesius, Zamkowa 4, 58-300 Walbrzych, Poland