Efficacy and Safety of Fully Resorbable Sinus Drug-eluting Stents in Patients With Eosinophilic Chronic Rhinosinusitis With Nasal Polyps After Surgery: A Prospective, Randomized Controlled Trial

Part A Inclusion Criteria: 1. Age 18-65 years. 2. Diagnosis of chronic rhinosinusitis with nasal polyps (CRSwNP). 3. Eosinophilic subtype confirmed by pathology (eosinophils \>27% of total infiltrating inflammatory cells in polyp tissue, OR absolute count \>55 eosinophils per high-power field (HPF) on H\&E staining). 4. Indicated and scheduled for Functional Endoscopic Sinus Surgery (FESS) due to inadequate response to standard medical therapy for \>3 months, with bilateral endoscopic Nasal Polyp Score (NPS) ≥5 (max 8), each side ≥2, and presenting at least 2 of the following symptoms before screening: nasal blockage/congestion, anterior/posterior nasal discharge, facial pain/pressure, or reduced/loss of smell. 5. Voluntarily participates, provides informed consent, and is able to complete questionnaires and follow-up visits. Exclusion Criteria: 1. Previous nasal surgery within 6 months before screening that altered lateral wall structure and precludes polyp assessment. 2. Allergy to corticosteroids or any component of the fully degradable sinus drug-eluting stent. 3. Severe systemic disease contraindicating surgery. 4. Other significant nasal diseases (e.g., sinonasal tumor, fungal sinusitis). 5. Uncontrolled systemic diseases (e.g., severe cardiac, hepatic, renal dysfunction, diabetes). 6. Recent use of steroids (30-day washout for parenteral, 14-day for oral, budesonide drops/irrigation, nebulized), immunosuppressants/biologics (within 5 terminal half-lives), or leukotriene antagonists/modulators prior to baseline. 7. Recent acute sinusitis episode. 8. Physical obstruction preventing access to any ethmoid sinus for stent delivery. 9. Known history or diagnosis of glaucoma, ocular hypertension, or posterior subcapsular cataract. 10. Pregnant or lactating women. 11. Participation in another clinical trial within the past 1 month. Part B Inclusion Criteria: 1. Age 18-65 years. 2. Diagnosis of chronic rhinosinusitis with nasal polyps (CRSwNP). 3. Eosinophilic subtype confirmed by pathology (eosinophils \>27% of total infiltrating inflammatory cells in polyp tissue, OR absolute count \>55 eosinophils per high-power field (HPF) on H\&E staining). 4. Early recurrence state: \>3 months post-FESS with standard therapy, no polyps (NPS=0), Lund-Kennedy (LK) edema score ≥2, and LK discharge score ≥2. 5. Voluntarily participates, provides informed consent, and is able to complete questionnaires and follow-up visits. Exclusion Criteria: 1. Postoperative polyp recurrence in ECRSwNP patients, with any side NPS \> 0. 2. Use of oral corticosteroids after the last FESS procedure. 3. Allergy to corticosteroids or any component of the fully degradable sinus drug-eluting stent. 4. Other significant nasal diseases (e.g., sinonasal tumor, fungal sinusitis). 5. Uncontrolled systemic diseases (e.g., severe cardiac, hepatic, renal dysfunction, diabetes). 6. Recent use of steroids (30-day washout for parenteral, 14-day for oral, budesonide drops/irrigation, nebulized), immunosuppressants/biologics (within 5 terminal half-lives), or leukotriene antagonists/modulators prior to baseline. 7. Recent acute sinusitis episode. 8. Physical obstruction preventing access to any ethmoid sinus for stent delivery. 9. Known history or diagnosis of glaucoma, ocular hypertension, or posterior subcapsular cataract. 10. Pregnant or lactating women.