How does a deviated septum affect the sinus enough to justify surgery?

Good question: Rhino-sinusitis is a viral/bacterial or rarely a fungal infection of the paranasal sinuses caused by obstruction of the very narrow entrances to the sinus cavities from the nose. As such, a deviated septum would have to be so severe as to obstruct those openings. However, your surgeon may opt to correct such a deviated septum, if access to the sinuses is obstructed by the septum.