Relationship between middle ear pressure,mucosal lesion,and mastoid pneumatization

Objectives: The inflammatory changes of pneumatic space mucosa are thought to affect the development of pneumatic space and the function of transmucosal gas exchange. So, it is assumed that the mucosal change is deeply involved in the onset and healing process of otitis media with effusion (OME). The objective of this study is to investigate whether the growth of the mastoid cells and the middle ear transmucosal gas exchange function in patients with OME are affected by the histopathologic changes in middle ear mucosa, and whether these two factors are changed by the treatment of OME. Materials and Methods: From 65 children with OME, middle ear mucosal specimens were collected during indwelling of a tympanic tube, and their histopathologic changes were compared with cell growth area measured on radiographic films and with the change in the middle ear total pressure (METP). Results: Suppression of the cell growth area was stronger and the METP stayed lower in cases with a higher degree of mucosal lesion. Significant expansion of pneumatic area was observed after 2 years of tube indwelling, and the peak METP showed a significant increase after 1.5 years. This increase in the METP was caused by diffusion/absorption of CO₂ and O₂ and indicated recovery of the transmucosal gas exchange function. Conclusions: The growth of the mastoid cells and the middle ear transmucosal gas exchange function are closely affected by the subepithelial histopathologic changes in middle ear mucosa, and these two factors recover by the treatment of OME.