Endoscopic endonasal surgery--concepts in treatment of recurring rhinosinusitis. Part I. Anatomic and pathophysiologic considerations.

Many years of endoscopic investigation and observation proved that most infections of the paranasal sinus are rhinogenic, spreading from the nose into the sinuses. The common focus of infection in cases of recurring sinusitis is the stenotic areas of the anterior ethmoid, with infection recurring in the larger sinuses. The anterior ethmoid, especially its infundibulum, is thus a key location for infection or cure, and maxillary as well as frontal sinuses are fully dependent on the pathophysiologic conditions there. Histologic examination demonstrates that massive changes of the nasal glands are the reason for permanent mucosal thickening. Retention cysts, highly viscous mucus, mucus extravasations, and metaplastic epithelial changes add to the vicious cycle of blockage of the ostium-meatus unit.