[Function of the eustachian tube in epitympanic retraction pockets].

There are different hypotheses for the development of epitympanic retraction pockets. These can occur as the result of an inflammatory process and negative pressure in the middle ear spaces. Anatomic bottlenecks in the middle ear favor diminished inflation of the epitympanic space. The eustachian tube provides pressure equilibration in the middle ear. Its dysfunction involving tubal opening or closing is thought to be the main reason for a permanent negative pressure in the middle ear. A patulous eustachian tube is now claimed for prolonged negative pressure in the middle ear and is caused by a so-called "sniffing" habit. The purpose of this study was to elucidate objectively the frequency of patulous eustachian tubes in ears with epitympanic retraction pockets. We examined passive tubal function in 41 patients with 50 epitympanic retraction pockets by using dual impedance in a pressure chamber. We identified three stages of epitympanic retraction pockets. Stage 1 involved a mobile and controllable retraction pocket; stage 2 corresponded with a fixed but controllable pocket, whereas stage 3 described a fixed pocket that was developing into a cholesteatoma. Results were compared with the function tests of 100 healthy ears in 50 normal individuals. We found 27 patulous eustachian tubes in patients with epitympanic retraction pockets, 22 of which occurred in affected ears while only 2 patulous tubes were found in the group of the healthy ears. Tubal opening pressure (P < 0.001) and tubal closing pressure (P < 0.01) were significantly lower in ears with epitympanic retraction pockets than in healthy ears.