[1] Mil Univ Hosp Prague, Dept Otorhinolaryngol & Maxillofacial Surg, Prague, Czech Republic
[2] Charles Univ Prague, Fac Med 3, Prague, Czech Republic
[3] Motol Univ Hosp, Dept Otorhinolaryngol & Head & Neck Surg, Prague, Czech Republic
[4] Charles Univ Prague, Fac Med 1, Prague, Czech Republic
[5] Mil Univ Hosp Prague, U Vojenske Nemocnice 1200, Prague 6, Czech Republic
[6] Third Fac Med, Dept Otorhinolaryngol & Maxillofacial Surg, U Vojenske Nemocnice 1200, Prague 6, Czech Republic