Position-Directed Budesonide Nasal Drops for CRS-associated Olfactory Dysfunction

This single-center randomized controlled trial evaluates whether budesonide nasal drops delivered in the Wu's position (Wu's 45° Head-Hanging Reclination Position) improve olfactory function more effectively than conventional budesonide nasal spray in adults with type 2 chronic rhinosinusitis (CRS)-related olfactory dysfunction. The study also evaluates patient-reported symptoms and quality of life, olfactory cleft structural abnormalities on sinus CT, computational fluid dynamics (CFD)-derived airflow parameters, safety, and whether baseline peripheral blood eosinophil count and clinical phenotype predict treatment response. The main questions this clinical trial aims to answer are: 1. Efficacy Comparison: Is olfactory improvement greater with olfactory cleft-targeted steroid nasal drops compared to standard nasal steroid sprays in CRS patients? 2. Mechanism Exploration: How do changes in inflammatory markers, obstruction severity, and olfactory test results explain the potential benefits of this treatment approach? 3. Disease Classification: Can post-treatment olfactory dysfunction be categorized as fully reversible, partially reversible, or non-responsive/irreversible using Week-12 TDI recovery?

Inclusion Criteria: 1. Men and women aged 18-65 years old. 2. Diagnosis of CRS according to the EPOS 2020, with olfactory dysfunction lasting ≥ 12 weeks. 3. Evidence of eosinophilic/type 2 inflammatory CRS, defined by at least one of the following: JESREC score ≥11, peripheral blood eosinophils ≥5%, absolute blood eosinophil count ≥ 0.25 × 10⁹/L. 4. Confirmation of OD via Sniffin' Sticks test: TDI score \