When does chronic sinusitis need surgery?

The American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) recommends offering functional endoscopic sinus surgery (FESS) to an adult with chronic rhinosinusitis (CRS) when the expected benefit of surgery exceeds the benefit of continuing medical treatment alone, the expected outcomes are clear, and the patient understands the need for long-term medical management after surgery. ^[1]

Key points of the AAO-HNS guideline (2025)

• The surgeon should not require a standardized, one-size-fits-all regimen or duration of medical therapy (antibiotics, steroids, antihistamines) as a mandatory condition before surgery — the decision should be individualized ^[1]
• The surgeon should identify the CRS subtypes that will benefit most from surgery: CRS with polyps, polyps with bone erosion, eosinophilic mucin, fungal balls ^[1]
• Early surgery is justified for fungal balls and AFRS (first line), neo-osteogenesis and bone erosion, severe polyposis with complete obstruction, and a risk of orbital/intracranial complications ^[1]
• Before surgery, the surgeon must confirm the diagnosis of CRS using established criteria (symptoms + objective findings) and assess candidacy based on symptoms, disease characteristics, quality of life and previous therapy ^[1]

Criteria for referral to surgery

Expert consensus and an NEJM review (Hopkins, 2019) define specific criteria for offering FESS in uncomplicated CRS with polyps: objective confirmation of CRS on CT + a minimum of 8 weeks of topical intranasal corticosteroids + 1–3 weeks of systemic corticosteroids + a persistent SNOT-22 score ≥ 20 after treatment. The AAFP recommendations (2023) state that referral for surgical assessment should be considered after at least 4 weeks, preferably 8 weeks, of nasal irrigation and intranasal corticosteroids. ^[2][3]

Evidence on the effectiveness of surgery

The MACRO study (Philpott et al., Lancet, 2025; a pragmatic multicenter three-arm RCT, n=457), the largest RCT on this question, showed that FESS provides a significant improvement in quality of life (SNOT-22) at 6 months compared with both clarithromycin and placebo, and the effect was the same in CRS with and without polyps. Long-term clarithromycin showed no benefit. A Dutch RCT (Lourijsen et al., Lancet Respir Med, 2022, n=234) also confirmed the advantage of FESS + medical therapy over medical therapy alone in CRSwNP (SNOT-22 difference −4.9 at 12 months), although the difference was below the minimal clinically important difference. ^[4][5]

In a large cohort study, the improvement in quality of life after FESS lasted up to 5 years. However, recurrent polyps are seen on endoscopy in 40% of patients at 18 months, and 20% of patients undergo revision surgery within 5 years. ^[2]

The role of biologic therapy

Three biologics are FDA-approved for CRSwNP: dupilumab (anti-IL-4/IL-13), omalizumab (anti-IgE) and mepolizumab (anti-IL-5). A systematic review by EAACI (2021, 1,236 patients) showed that dupilumab most effectively reduces the need for surgery (RR 0.28) and improves quality of life (SNOT-22 −19.14). The AAAAI recommendations (2023) conditionally suggest biologics for CRSwNP, stressing that the decision depends on the response to other treatments (intranasal corticosteroids, surgery, aspirin desensitization) and the patient’s preferences. ^[6][7][8][9]

The question of “biologics before or after surgery” remains open. The AAO-HNS (2025) notes that some data support reserving biologics for refractory disease after primary surgery, given the cost and uncertain duration of therapy. However, patients with high baseline severity and comorbid asthma may prefer biologics before surgery. ^[1][8][9]

Summary table of indications for FESS