Isolated congenital stapes suprastructure fixation

Isolated congenital anomalies of the ossicles are rare. The majority of cases of congenital conductive hearing loss secondary to middle-ear anomalies have other associated defects, such as atresia, microtia and craniofacial deformities. We present a rare case of isolated congenital stapes suprastructure fixation, where a monocrural stapes with a mobile footplate was attached to the promontory by bony synostosis. There was no stapedius muscle nor pyramidal process. The incus and malleus were of normal configuration. Mobilization of the stapes from the promontory resulted in improvement in hearing. We believe this is the first reported case of such an abnormality. A review of the world literature of isolated stapes suprastructure ankylosis and the classifications of minor congenital anomalies are discussed.