Evaluation of eustachian tube CT measurements in patients with COM and cholesteatoma

Chronic otitis media [COM] is a long-term infection of middle ear and mastoid cavity with frequent ear discharges through a tympanic perforation. Eustachian tube measurements done using High Resolution Computed Tomography [HRCT] would be helpful in determining the influence of it in the development of COM and cholesteatoma. The aim of study is to compare the ET measurements in patients having COM without Cholesteatoma, COM with Cholesteatoma and normal ears. This is a retrospective study. A total of 79 patients (47 males, 32 females, age range: 15-81 years) referred for temporal bone from June 2016 to June 2018 were included. Of 79 patients, Group A included 54 ears who had COM without cholesteatoma (26 Unilateral, 14 Bilateral) and Group B included 49 ears who had COM with cholesteatoma (29 unilateral and 10 Bilateral). Patients who underwent HRCT PNS with no pathologies related to middle ear were included as controls. Group C included 158 ears (79 patients) with normal ears. The ET angle with respect to Reid’s plane (ETA), Tubotympanic angle (TTA), Pretympanic diameter (PTD) was measured between the three groups. The mean ETA, TTA, PTD measured for groups A, and B was 24.30±1.6°, 146±3.2°, 5.5±2.2 mm, & 21.18±1.4°,148±4.2°, 4.1±2.1 mm respectively, where as in Group C it was 26.20±1.7°, 143±2.7°, 6.5±2.4 mm respectively. From our study we conclude that reduced ETA, increased TTA and reduced PTD may be predisposing factor in the development of COM and Cholesteatoma.