Unoperated sinuses or cases with gross sinus ostial obstruction will not be reliably penetrated by sinus irrigant. A 3.95-mm ostial diameter seems to be the minimum size to guarantee penetration in paranasal sinuses to maximize the potential for topical sinus treatment.

Clinical and microbiological relapse of disease following ESS is significantly associated with intracellular S. aureus. Evidence suggests that this disease association is independent to surface biofilm status. Intracellular bacteria should be taken into consideration when designing novel treatment strategies to lessen the chance of reinfection.

S. aureus biofilm formation varies across exposure to different NO levels, with antibiofilm effects at higher concentrations, and enhanced biofilm formation at lower or subphysiologic concentrations. These results coincide with the often dualistic function of NO, and have implications in its future use in the treatment of CRS.