Author contribution: Bomshteyn NG, Bolotov YuV — study concept and design, data acquisition and processing, manuscript writing; Kim IA, Trukhin DV — study management, manuscript editing.

Compliance with ethical standards: the study was approved by the Ethics Committee of the Scientific and Clinical Center of Otorhinolaryngology of the Federal Medico-Biological Agency of the Russian Federation (protocol № 02/20 dated April 13, 2020). All patients submitted the informed consent to participation in the study.