KUMJ | VOL. 24 | NO. 3 | ISSUE 96 | JULY-SEPTEMBER, 2026

Computed Tomography Analysis of Sinus Tympani in Nepalese Population
KC AK, Amatya N, Shrestha BL

Abstract:
Background Sinus tympani is a hidden recess in the retrotympanum with variable anatomy in terms of shape and size. This area is frequently involved in middle ear diseases and surgical removal of disease is particularly difficult, often leading to residual disease. However, its morphology has not yet been studied in the Nepalese population. Objective To evaluate the morphology of sinus tympani using axial view of high-resolution computed tomography (HRCT) scans. Method A retrospective cross-sectional study was conducted at Dhulikhel Hospital, Kathmandu University Hospital. High-resolution computed tomography temporal bone scans of patients 18 years and above acquired between January 2021 and December 2021 with adequate imaging quality were included, whereas cases with congenital ear malformations, previous history of tympanomastoid surgery, temporal bone trauma and malignancy were excluded. Axial images were assessed independently by three observers and the sinus tympani was classified into Types A, B and C according to its relationship with the mastoid segment of the facial nerve. Result A total of 92 patients were included in the study with a total of 180 ears being studied. Patients ranging in age from 18 years to 77 years (Mean age 35.7 years) were included. 123 ears (68.3%) had chronic otitis media. Radiomorphological configuration of sinus tympani was found to be Type A (limited sinus tympani) in 65%, Type B (deep sinus tympani) in 32%, and Type C (deep sinus tympani with posterior extension) in 3%. Conclusion Radiomorphological classification of sinus tympani is an essential tool for preoperative planning.
Keyword : High-resolution computed tomography, Radiomorphological, Sinus tympani