Oval window absence, bony closure of round window, and inner ear anomaly.

Abstract

AbstractUnusual temporal bone findings are presented in a seven‐and‐one‐half‐year‐old female with marked hearing impairment and multiple congenital anomalies. The oval window was absent bilaterally, with no stapedio‐vestibular joint development on the right side and incomplete development on the left side. The round window membranes were normal, but on the left side the round window niche was walled off from the middle ear by bone continuous with the periosteum of the middle ear surface of the otic capsule. Surgically, this would have been interpreted as congenital absence of the round and oval windows. It should be recognized that the round window membrane may be present in the absence of an open round window niche. Bilaterally the cochlea consisted of 13/4 turns, and on the left side, the scalae tympani ended blindly in the second turn so that no helicotrema was present. Spiral ganglion cells were markedly reduced on the right side and entirely absent on the left, where there was marked thickening of the cribriform base of the cochlea. The organ of Corti was present in all turns. The bony semicircular canals were not formed.The embryological development and interference with development which probably resulted in these malformations are discussed.Oval window absence or congenital footplate fixation should probably be referred to as varying degrees of stapediovestibular joint malformation.