Diagnosing patulous Eustachian tube dysfunction using the nine-step and inflation tests

Abstract

This study evaluated the diagnostic value of the nine-step test and an inflation test for patulous Eustachian tube (PET). We prospectively analyzed 27 ears from 18 patients with definite PET who underwent ventilation tube insertion, and 18 ears from 18 control participants with traumatic or iatrogenic tympanic membrane perforations. All participants underwent both the nine-step test (performed on intact tympanic membranes [TMs]) and inflation test (performed on TMs with a ventilation tube or perforation), in which only the inflation phase of the inflation-deflation test was performed. Diagnostic markers for PET included the middle ear pressure in the resting state, maximal peak pressure difference (ETTmd) from the nine-step test, and opening pressure (OP) and closing pressure (CP) from the inflation test. The diagnostic performance and optimal cutoff values were assessed using receiver operating characteristic analysis. The ETTmd values and the OP and CP values were significantly lower in the PET group than in the control group. The middle ear pressure in the resting state did not differ between the two groups. The inflation test exhibited moderate diagnostic accuracy, with an area under the curve of 0.864 and 0.826 for OP and CP, respectively. The optimal cutoff values for a PET diagnosis 277.5 daPa for OP and 31 daPa for CP. These findings suggest that the nine-step and inflation tests are complementary tools for diagnosing PET, particularly in patients with perforated tympanic membranes.