The missed ostium sequence and the surgical approach to revision functional endoscopic sinus surgery.

Maxillary sinus disease often is exacerbated by a laterally displaced uncinate process that functionally obstructs the infundibulum and the natural ostium. The drainage pathway may be adequate during periods of wellness but with the introduction of nasal edema, the ostium/infundibulum interface is inadequate, thus preventing acceptable ventilation and drainage. Incomplete removal of the most anterior uncinate can keep the surgeon from identifying the natural ostium. Failure to relieve any obstruction from this important opening, with simultaneous creation of an MMA that does not include the natural ostium of the maxillary sinus, leads to the missed ostium sequence and continued sinus disease.