Patient follow-up
All patients were followed up over a 2-year time period at 9 different time points. Patients were recruited and then had a 4-week washout period for all systemic and topical steroids as well as antibiotics. The first time point was preoperatively on the day of surgery. The remaining 8 postoperative time points were at 3 weeks, 1.5, 3, 6, 9, 12, 18, and 24 months after FESS.