Effect of tubal occlusion on bone formation in the middle ear of the rat.

The effect of experimental occlusion of the Eustachian tube in rats have been studied. Only in germ-free animals it has been possible to eliminate infection as a complicating factor. The formation of new bone in the wall of middle ear and bulla was apparent soon after occlusion, even in the absence of infection. These findings suggest that tubal occlusion causing serous otitis media can lead to extensive changes in the bone lining the middle ear cavity and this could explain the condensation of bone found in ears without any apparent sign of infection.