Comparative preoperative evaluation of eustachian tube function in pathological ears.

On 100 pathological ears with tympanic membrane perforation, eustachian tube functions was measured by using sonotubometry and the negative pressure equalization test in an attempt to compare these two methods. The pressure equalization test did not appear to be a reliable tool for preoperative clinical determination of tube function because sonotubometry showed tubal opening in 85% (myringoplasty group) and in 49% (radical surgery group) of patholoical ears, which were not able to equalize negative middle ear pressure at all during swallowing. The negative pressure equalization test is considered to be unphysiological and may produce a locking phenomenon of the tube. Even a small negative pressure can act like a valve, producing an obstruction that muscle activity of the tube is no longer able to overcome particularly when mucosal changes are present in the tubal orifice. Sonotubometry is a physiological test and as such gives a reliable picture of the opening of the tube during swallowing. Data on tympanic aeration postoperatively will be reported later.