[Functional aspects of endoscopic surgery of the fundus of the frontal sinus].

Obstruction of the ostium frontale leads to hyperplasia of the mucosa in the cranial part of the sinus frontalis and caudal of the recessus frontalis. The velocity of air flow in the ostium frontale can be recorded by means of thermistor anemometry after elimination by endoscopy, of the obstruction to drainage and to ventilation in the ostium frontale. The method of functional examination by contrast yields information on the postoperative flow of secretion. Mucociliar transportation, which shows that normal functions have been resumed, can be demonstrated accurately by endoscopy of the nose after the application of colouring matter. The exact indication for radical operation can be determined in this manner.