[Study on the phenomenon of regionally pathological difference of otitis media and its clinical significance].

OBJECTIVE: To study the feature and difference of severity of pathological changes in different areas of the middle ear cleft with otitis media (OM) and its pathogenesis and clinical significance. METHODS: The temporal bone slides of 290 ears with OM with inflammatory effusion had been studied histopathologically under microscope. The histopathological change in different areas has been comparatively observed. 256 cases with various forms of chronic otitis media (COM) have been studied with high-resolution CT, and 189 cases with COM were observed during operation, stressing on the difference of pathogical changes in different areas. RESULTS: In the process of OM, the mucosa of the eustachian tube almost has no inflammatory pathological changes, and in hemi-anterior and infer-posterior mesotympanum area was much lightly and reversible pathological change. But the pathological changes in the ossicular chain area was much more serious than the other two areas, and was irreversible or intractable such as granulation tissue, cholesteatoma etc. CONCLUSIONS: Because of the historical and anatomical distinction difference between anterior and posterior area of the middle ear cleft and blockage of internal ventilation/draining system in process of OM, the stagnancy of inflammatory effusion and formation of granulation tissue in posterior area are the main cause leading to the phenomenon of regionally pathological difference in different areas of the middle ear clefts.