A possible role of aerodynamic factors in nasal polyp formation

Nasal polyps are apparently the result of multiple deleterious influences acting together. For the establishment of nasal polyps, not only are specific inflammatory changes in the nasal mucosa required but also accessory factors that render the inflamed mucosa susceptible to polyp formation. In this study, it was demonstrated that the unilateral polyposis in patients with deviated septum occurred much more frequently on the concave side (33:14). Inflammatory factors affect both sides equally but the deviated septum influences the air flow through the nasal cavities separately. The air flow rate on the concave side is greater than on the convex side. Since the upper part of the lateral wall of the nasal cavity where polyps occur is the most constricted, the air currents are most rapid and then the air pressure is decreased, tending to form an area of negative pressure. It appears that the negative pressure induces the inflamed mucosa to project into the nasal cavity resulting in polyp formation.