Postinflammatory ossicular fixation: CT analysis with surgical correlation.

Postinflammatory ossicular fixation is a common problem encountered by the otologic surgeon upon exploration because of conductive hearing loss in patients with chronic otitis media. These nonotosclerotic noncongenital lesions take three pathologic forms: fibrous tissue fixation (chronic adhesive otitis media), hyalinization of collagen (tympanosclerosis), and new bone formation (fibro-osseous sclerosis). Fibrous tissue fixation appears on CT as nonbony, noncalcific soft-tissue debris encasing some or all of the ossicular chain. Tympanosclerosis appears as unifocal or multifocal punctate or weblike calcifications in the middle ear cavity or on the tympanic membrane. This debris may be in direct apposition to the ossicular chain or may replace the suspensory ligaments in symptomatic patients. New bone formation has been identified only in the attic and is the least common manifestation. Thick bony webs or generalized bony encasement may be present at CT. More than 300 patients with the clinical diagnosis of chronic otitis media have been examined. This study encompasses 23 proved cases.