1. Department of Otorhinolaryngology, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava, Czech Republic
2. Department of Otorhinolaryngology and Head and Neck Surgery, Faculty of Medicine in Hradec Kralove,University Hospital Hradec Kralove, Charles University in Prague, Sokolska 581, 50 005 Hradec Kralove, Czech Republic