Prescription Patterns and Outcomes of Topical Antibiotic Irrigations in Difficult-to-Treat Chronic Rhinosinusitis

Background A substantial proportion of patients with chronic rhinosinusitis (CRS) remain partly controlled or uncontrolled despite endoscopic sinus surgery (ESS) and maximal medical therapy. For these difficult-to-treat cases, topical antibiotic irrigations have been proposed as an adjunctive therapy, particularly when delivered via large-volume, low-pressure systems that enhance sinus penetration post-ESS. Evidence on their efficacy and prescribing patterns in this population remains limited. Objective This study aims to evaluate the use and outcomes of topical antibiotic irrigations in patients with difficult-to-treat CRS. Methods A retrospective, multi-site cohort study was conducted across tertiary academic medical centers. Adult patients with persistent CRS symptoms despite bilateral full-house ESS and conventional postoperative medical management were included. Patients with cystic fibrosis or granulomatosis with polyangiitis were excluded. Demographic, clinical, and treatment data were collected. Primary outcomes were infection resolution at 8 weeks and changes in Sino-Nasal Outcome Test-22 (SNOT-22) scores. Results Sixty-seven patients met inclusion criteria. Mupirocin (41.8%), tobramycin (23.9%), and gentamicin (17.9%) were the most commonly prescribed agents. After 8 weeks, 62.7% of patients achieved infection clearance. Among 44 patients with SNOT-22 data, scores improved significantly from 34.8 ± 20.2 to 21.8 ± 14.7 ( P < .001). Improvement in SNOT-22 scores was more pronounced in patients who cleared the infection compared to those who did not. Conclusion Large-volume topical antibiotic irrigations were associated with high infection resolution rates and clinically meaningful SNOT-22 improvements in patients with difficult-to-treat CRS. These findings support their potential utility as an adjunctive therapy in select postsurgical patients and warrant further prospective investigation.