Statistical analyses were performed using SPSS software. The paired series involved a comparison test used to assess duration of effectiveness, pre- and postoperative differences in nasal obstruction VAS, olfactory disorders VAS and pre- and postoperative differences in NPS. The significance level was set at 0.05 for all analyses. The highest NPS from both the right and left nasal fossae was used for statistical analyses. Student’s mean comparison test was used to evaluate the influence of factors potentially affecting our results. Gender, asthma or AERD, history and number of sinus surgeries, preoperative NPS, hypereosinophilia, cardiovascular history and diabetes were tested. Survival analysis was performed using the Kaplan-Meier method to determine non-recurrence. The log-rank test was performed to evaluate the influence of factors potentially affecting recurrence.