Abstract
During tympanoplasty for various kinds of otitis media, two cases of osseous malleus fixation and two cases of osseous incus fixation were encountered accidentally. One case was a bony fixation of the malleus head by an anterior tympanic bony spur; wich was named by DAVIES in 1968. The others cases were caused by postinflammatory new bone formation. Each of these fixation was corrected using a low speed diamond burr (Tip: 1/2mm) without disrupting the ossicular chain. All cases had an air-bone gap of 15 dB or less for the speech frequencies and had no significant inner ear disturbances after surgery. The bone-conduction threshold for speech frequencies were improved in three cases after surgery. From the experiencies of these cases, osseous fixation of the lateral ossicle (malleus and incus) should be considered in addition to otosclerosis when diagnosing combined hearing losses with an intact tympanic membrane.
