RESUMO
Reduced mastoid pneumatization has been seen in most patient with chronic otitis media [COM] disease. In this study we decided to measure the distance between sigmoid sinus [SS] and posterior wall of external auditory canal[EAC]as an index of mastoid pneumatization before disease and explore the correlation between this distance and different type of COM disease. This cross-sectional study was carried out between 1381-1382 years at Shafa hospital in Kerman. The distance between SS and post wall of EAC which extracted from Schuller graphy was compared with that was measured in surgery. 51 patients with COM disease were subjected to mastoidectomy included in this study. The mean distance between SS and posterior wall of EAC in patients with type III disease [10.14 +/- 5.06 mm] was remarkably smaller than patients with type I and II of disease [15.03 +/- 6.03]. This study revealed that patients with smaller mastoid air tank are susceptible to more severe form of COM diseases