Safety and Efficacy of the Propel Mini and Propel Nova Steroid-Eluting Sinus Implant in Frontal Sinus

Inclusion Criteria: * Patient has CRS confirmed by CT scan and defined as symptoms lasting longer than 12 consecutive weeks in duration with inflammation of the mucosa of the nose and paranasal sinuses. * Patient has a clinical indication for and has consented to ESS including bilateral frontal sinus surgery. * Chronic sinusitis diagnosis confirmed and documented by CT scan within 6 months of the procedure. * Patient has bilateral disease in both frontal sinuses confirmed by Lund-Mackay score of ≥1 on each side. * Planned sinus surgery includes bilateral ethmoidectomy (if judged necessary) and frontal sinus enlargement using Draf II (A or B) dissection or balloon dilation, with minimum of 5-mm diameter opening created. * Technique used for frontal sinus surgery is the same on both sides (e.g. surgical dissection alone bilaterally, balloon dilation alone bilaterally, or both bilaterally) * Septoplasty for access to the ostio-meatal complex is permitted. * ESS including bilateral frontal sinus surgery 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. Exclusion Criteria: * Known history of immune deficiency such as immunoglobin G or A subclass deficiency, or Human Immunodeficiency Virus (HIV) * Oral-steroid dependent condition such as chronic obstructive pulmonary disease (COPD) or asthma or other condition * Known history of allergy or intolerance to corticosteroids or mometasone furoate * Clinical evidence of acute bacterial sinusitis * Clinical evidence or suspicion of invasive fungal sinusitis (e.g., bone erosion on CT scan, necrotic sinus tissue) * Active viral illness * Concurrent condition requiring active chemotherapy and/or immunotherapy management for the disease * Clinical evidence of disease or condition expected to compromise survival or ability to complete follow-up assessments during the 90 day follow-up period * Currently participating in another clinical trial * History of insulin dependent diabetes mellitus * Patient has previously undergone ESS and experienced a CSF leak or has compromised vision as a result of a complication in a prior ESS procedure * Significant complication during the current frontal sinus surgery procedure such as excessive blood loss, CSF leak or punctured lamina papyracea * Current ESS including frontal sinus surgery is aborted for any reason. * At least one side is not amenable for implant placement.