Inclusion Criteria:  Symptomatic CRSwNP patients without improvement after conservative treatment for at least 6 months Extent of disease at least Davos Polyp Score ≥ 4 points Age 18-65 years Signed consent  Exclusion Criteria:  Previous sinunasal surgery High resolution paranasal sinus CT shows other pathology (e.g. mucocele) Incapable of judgement