Sonotubometry in chronic ear disease.

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.