V.N. Perevozchikova - Post-graduate Student, Department of otorhinolaryngology, North-Western State Medical University I.I. Mechnikov, St.-Petersburg, Russia. E-mail: verashka2@rambler.ru
N.N. Petrova - Ph.D. (Med.), Professor, Department of otorhinolaryngology, North-Western State Medical University I.I. Mechnikov, St.-Petersburg, Russia. E-mail: Natalya.Petrova@spbmapo.ru
Y.A. Maslova - Post-graduate Student, Department of otorhinolaryngology, North-Western State Medical University I.I. Mechnikov, St.-Petersburg, Russia. E-mail: ulenka7@rambler.ru