[Experimental studies of the effect of nasal respiratory obstruction on ventilation of the maxillary sinus].

The connection between obstruction in the nasal cavity and the antral ventilation is not completely understood. To investigate this problem, experiments with a tube model and a plastinated model of a human nose have been performed (see Fig. 1). It was possible to take the septum off that model to replace it by different septal deviations or to imitate adenoidal hyperplasia. Furthermore, the antral ostium was replaced by cannules of different sizes (0.38-7.06 mm2). Thus, we were able to record the resistance of the nose, the pressure in front of the ostium and the pressure in the sinus synchronously. We were able to show that the antral pressure depends on the depth of breath and its frequency, the choanal pressure, the resistance of the total nose, the localisation of septal deviations in the cavity of the nose and the size of the ostium (see table 1). Proximal obstructions in the nasal cavity--such as adenoidal hyperplasia--caused a diminishing antral pressure amplitude during respiration, distal obstructions caused an increase of the antral pressure (see Fig. 3). Accordingly, the isthmus nasi is a physiological distal obstruction which causes an amelioration of the sinus ventilation. If the ostial surface is reduced to below 1 mm2, there is a time delay of the pressure in front of and behind (i.e. in the sinus) the ostium (see Fig. 2). This means a reduction of the antral pressure amplitude depending on the frequency of respiration.(ABSTRACT TRUNCATED AT 250 WORDS)