Objective:To describe the radiologic dimensions of the Eustachian tube (pre-tympanic diameter, tubo-tympanic angle, and Eustachian tube angle) among normal ears, ears with chronic otitis media (COM) with and without cholesteatoma, in a sample of Filipino adults with COM; and to compare the dimensions of the three variables.

Methods:
Design:Retrospective Review of Records
Setting:Tertiary Government Training Hospital
Participants:The study included 69 CT scans of adults with COM, with images of 23 ears for each variable (normal ears, COM with and without cholesteatoma formation).

Results:In normal ears, the average pre-tympanic diameter was 3.976 ± 0.78 mm, the average tubo-tympanic angle was 41.529 ± 5.85 degrees, and the average Eustachian tube Angle (Reid Plane) was 27.077 ± 4.62 degrees. In patients with COM without cholesteatoma, the mean pre tympanic diameter was 4.002 ± 1.13 mm, the mean tubo-tympanic angle was 141.994 ± 6.30 degrees, and the mean measurement of the Reid plane was 24.649 ± 3.10 degrees. In ears with COM with cholesteatoma, the mean pre-tympanic diameter was 4.1993 ± 0.50mm, the mean tubo-tympanic angle was 138.789 ± 7.13 degrees, and the mean Reid plane was 26.483 ± 3.86 degrees. P-values for the pre-tympanic diameter, tubo-tympanic angle, and ET angle were .617, .198, and .098 respectively, indicating that there were no statistically significant differences in the ET dimensions of the ears with COM with cholesteatoma, without cholesteatoma and normal ears.

Conclusion:In our investigation, we found no statistically significant differences in Eustachian tube dimensions among individuals with normal ears and COM with or without cholesteatoma. This suggests that the Eustachian tube dimensions may not serve as a primary etiological factor for COM among our patients.