Abstract
Using scanning and transmission electron microscopes, human middle ear mucosae, 6 normal, 3 with chronic inflammation, 11 obtained during second stage tympanoplasty were investigated with respect to regeneration of the mucosa. The normal mastoid mucosa was lined with a layer of non-ciliated and ciliated cells which were tightly connected by desmosomes. The ciliated cells were scattered in the non-ciliated cells. The area occupied by the ciliated cells measured less than 6%. In the mastoid with chronic inflammation, ciliated cells disappeared or decreased in number.The epithelia showed metaplasia into the stratified squamous epithelium. Exposure and rupture of the basement membrane were often observed. The mucosae obtained during the second stage tympanoplasty carried out six months or more after the first operation showed: 1) Almost normal mucosa regenerated where the inflammation had cleared and the aerated tympanic cavity was reconstructed. 2) Even if there was a residue of small cholesteatoma, the mucosa regenerated normally where the inflammation had subsided. 3) The epithelium regenerating after removal of granulation showed a closer proximity to the normal than that after removal of cholesteatoma. 4) The middle ear epithelium was in the process of regeneration and differentiation six months after the first operation.
