This randomized study compares operative techniques in chronic rhinosinusitis with polyposis (CRSwNP) surgery. It aims to evaluate outcomes in asthma and CRSwNP, safety and costs. The investigators want to see if patients with certain clinical and/or genetic predispositions will benefit from extended surgery. They also aim to find biomarkers for detection and management models for of severe airway inflammation and to further develop markers for progressive disease forms.

Please see study protocol

Inclusion Criteria:

• Patient not responding to conservative treatment of 3 months of nasal steroid drops
• Nasal polyp score ≥ 4/8
• SNOT-22 ≥ 30
• Lund-Mackay CT score ≥ 14
• One previous endoscopic sinus surgery or at least one peroral corticosteroid course or at least 3 courses of antibiotics within 2 years

Exclusion Criteria:

• Age <18 years, age > 65 years
• Complication of CRS (f.e. mucocele, invasive fungal rhinosinusitis)
• Other diagnosis than CRSwNP (inverted papilloma, antrochoanal polyp etc.)
• Previous external sinus surgery or Draf 3 procedure (or indication for external approaches or Draf 3
• Bleeding diathesis
• Pregnancy/ breastfeeding
• Cystic fibrosis
• Primary ciliary dyskinesia (PCD)
• Sarcoidosis
• Granulomatosis with polyangitis (GPA)
• Eosinophilic granulomatosis with polyangitis (EGPA)
• Immunosupression (diagnosed Spesific Antibody Deficiency (SAD), common variable immunodeficiency (CVI), HIV or use of biologicals/immunosuppressive medication)
• Immunotherapy
• Daily use of systemic corticosteroids
• Communication problems (f.e. neurological/psychiatric disease, language skills)
• Unlikely to comply
• Other severe disease
• Inability to be operated.

Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures and appendices) can be shared.

Beginning 3 months and ending 3 years after article publication.

Researchers who provide a methodologically sound proposal.