Statistical analysis
The sample size of this study was estimated according to a study by Harvey RJ. et al.(9) , determining the sample size based on two independent mean formulas using type I error (alpha) of 0.05 and a power of 0.8. The authors consider the sample size of 70 in total numbers as the most appropriate to detect a significant difference between groups. Further, data loss was estimated at 15%; the final estimation for the total sample size was 80. Each side of the paranasal sinus system representing its distinct fluorescein stain; thus, the sample size in the study was defined as the number by the side of the nostril with reference to 40 subjects in total.
Baseline characteristics were described using mean and standard deviation for continuous variables and percentage for categorical variables. Interrater reliability testing for fluorescein grading scores by two assessors was determined by the concordance correlation coefficient. The comparison of outcomes was performed using a linear mixed-effects model for analysis. All analyses were performed using Stata version 13.0 (StataCorp, College Station, TX). All test statistics were reported in terms of magnitude of effect with mean difference and 95% confident interval (CI), where a p -value of less than 0.05 was considered statistically significant.