Inclusion Criteria:  Age ≥18 Diagnosed as having CRS Undergone at least 2 trials of medical treatments in the past Mean 3 cardinal symptom (3CS) score Bilateral ethmoid disease confirmed on CT Has been informed of the nature of the study and provided written informed consent Agrees to comply with all study requirements  Exclusion Criteria:  Inability to tolerate topical anesthesia Previous nasal surgery Presence of nasal polyp grade 2 or higher Seasonal allergic rhinitis Perennial rhinitis with symptoms that are well controlled by regular use of intranasal corticosteroids Severe asthma History or clinical evidence or suspicion of invasive fungal sinusitis, allergic fungal rhinosinusitis, atrophic rhinitis, or odontogenic sinusitis Obstruction preventing proper placement and retention of LYR-210 as seen on endoscopy Anatomic variation that, in the opinion of the investigator, would adversely impact placement of LYR-210 as seen on CT Known history of hypersensitivity or intolerance to corticosteroids Known history of hypothalamic pituitary adrenal axial dysfunction Previous pituitary or adrenal surgery Dental procedure/implant on maxillary dentition within 4 weeks of the Screening visit. Past or present acute or chronic intracranial or orbital complications of CRS History or diagnosis (in either eye) of glaucoma or ocular hypertension Past or present functional vision in only 1 eye Past, present, or planned organ transplant or chemotherapy with immunosuppression Currently positive for COVID-19 or residual sinonasal symptoms from a previous COVID-19 infection Pregnant or breast feeding. Females of child-bearing potential must test negative for pregnancy at the time of screening Evidence of disease or condition expected to compromise survival or ability to complete follow-up assessments Currently participating in an investigational drug or device study Determined by the investigator as not suitable to be enrolled