Pathology of the ossicular chain in various chronic middle ear diseases.

In a collection of 1,100 operated ears, 426 of which had cholesteatoma and 674 had not, the various defects of the ossicular chain are described and related to the nature of the disease and the site of perforation. The analysis showed marked differences between the various diseases and in the frequency of the individual ossicular defects or combinations of defects. Defects of the head of the malleus and of the body of the incus were found exclusively in chiolesteatomas, most often those affecting the attic. Isolated defects of the malleus handle were most common in cholesteatoma of the parts tensa and in total perforations. Defects of the long process of the incus occurred in 74--88 per cent of cholesteatomatous diseases, defects of the stapedial arch in 47 per cent of ears with sinus cholesteatoma. In granulating otitis without cholesteatoma and in sequelae to otitis there was less ossicular pathology, and 57 per cent of these ears had an intact ossicular chain. Total or posterior perforations were associated with pathology of the ossicles more often than inferior or anterior perforations. All cases with destruction of the body of the incus and the head of the malleus showed squamous epithelium in close relation to the ossicular defect, indicating a marked--presumably enzymatic--influence by the squamous epithelium upon the bone resorption.