Abstract
The effects of long-term tubal occlusion on the pneumatization of tympanic bullae were investigated in this study. Eight piglets were used, and bilateral pharyngeal orifices of the eustachian tube were cauterized by an electrocoagulator. Six months after cauterization, the piglets were decapitated and the tympanic bullae were removed. The majority of the cauterized tubal orifices were completely occluded. In these cases, viscous middle ear effusion was seen and pneumatization of the tympanic bullae was inhibited by inflammation and increased bone mass. These inflammatory changes were more intense and the bone tissue occupied a larger proportion of the tympanic bullae than in the short-term models of our previous study.
