• Aeration of the tympanic cavity was studied after 81 operations were performed on ears with cholesteatoma, in which sonometry was used preoperatively to measure the eustachian tube (ET) function. Twenty-nine of the 44 ears in which all or part of the tympanic mucosa could be preserved had positive sonometric test results, and 25 ears (86%) retained satisfactory aeration. Eight (53%) of the 15 ears with negative test results showed good postoperative aeration while adhesive changes developed in seven ears (47%). In 37 ears after the removal of all tympanic mucosa, aeration was satisfactory in eight (55%) of the 15 ears with positive sonometric test results, whereas only three (14%) of the 22 ears with negative test results developed an aerated tympanum. A positive sonometric test result can be regarded as a fair prognostic indicator of normal ET function. In extensive tympanic disease, there is a clear correlation (86%) between a negative test result and postoperative adhesion.
(Arch Otolaryngol 1984;110:596-599)