Pre- and postoperative sinus penetration of nasal irrigation.

OBJECTIVE/HYPOTHESIS Endoscopic sinus surgery is an accepted treatment for medically recalcitrant chronic rhinosinusitis. Effective saline douching may improve long-term outcomes of chronic rhinosinusitis but is often impaired by postoperative ostial stenosis. The aim of this study is to determine a critical ostial size at which douching solution reliably enters the sinus cavities. STUDY DESIGN Prospective study of consecutive patient cohort. METHODS Seventeen preoperative or well-healed postoperative endoscopic sinus surgery patients were irrigated with 5 mL blue food coloring mixed with 200 mL buffered saline from a squeeze bottle. The degree of sinus penetration, sinus ostial patency, and ostial size were endoscopically determined. RESULTS Sinuses penetrated by blue dye had a significantly larger minimal ostial dimension (7.31 mm; 95% confidence interval 5.54-9.08) than those that had no blue dye penetration (1.26 mm; 95% confidence interval 0.86-1.66) as determined by Student t test. Chi-square analysis showed that operated sinuses were more likely to be penetrated than nonoperated sinuses (P = .0016) and obstructed sinuses (P = .0325). Logistic regression showed a 95% probability of penetration when the minimum ostial dimension is 3.95 mm or greater. CONCLUSIONS 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.