Functional endoscopic surgery of the nose and paranasal sinuses. This modern method of treating ENT conditions involves a minimally invasive procedure performed inside the nasal cavity using microsurgical instruments and specialised magnifying endoscopic optics. The procedure is designed to preserve and restore the normal function of the mucous membranes in the nasal cavity and sinuses as much as possible. It helps improve nasal breathing, air humidification, mucus drainage, and local immune function within the nasal cavity.