The PIO (Propel In Office) III Study of In-office Placement of a Steroid-Eluting Implant Immediately Following Ethmoid Sinus Surgery

Inclusion Criteria: * Age ≥ 18 years * Confirmed diagnosis of CRS (Chronic Rhinosinusitis) based on the 2015 Clinical Practice Guideline for Adult Sinusitis \[6\] * Prior ESS (Ethmoid Sinus Surgery) including bilateral total ethmoidectomy at least 90 days prior to being considered for this study * Planned ESS includes bilateral polypectomy * ESS including bilateral polypectomy has been successfully completed without significant complication that, in the opinion of the investigator, would confound study results, and the patient's anatomy remains amenable to implant placement. * Bilateral polyposis (minimum grade 2 on each side) originating from the ethmoid sinus region * Complaints of at least 2 of the 5 hallmark symptoms of chronic sinusitis: nasal obstruction/congestion, post-nasal discharge, thick nasal discharge, facial pain/pressure, or decreased sense of smell. * Minimum symptom threshold (Nasal Obstruction/Congestion minimum score of 2 on scale from 0 to 3) * Failed medical therapy within the preceding 12 months Exclusion Criteria: * Not able to give consent * Oral-steroid dependent condition * Allergy or intolerance to corticosteroids * Clinical evidence of bacterial sinusitis or invasive fungal sinusitis * Pregnancy