Isolated primary unilateral stenosis of the internal auditory canal.

Congenital primary stenosis of the internal auditory canal (IAC) may exist in isolation or along with a number of other osseous anomalies of the temporal bone. Most of the literature on IAC stenosis is concerned with its effect on the outcome of cochlear implantation (i.e. patients with profound bilateral hearing loss). In addition, some degree of canal asymmetry has been noted in patients with normal hearing, questioning the causal relationship of this finding to deafness. We describe two children with computed tomography (CT) documented severe primary unilateral narrowing of the IAC and an associated ipsilateral sensorineural hearing loss. Typical radiographic findings are described, and the relevant developmental pathology is discussed. The ipsilateral association of stenosis and hearing loss strengthens the link between narrowing of the IAC and deafness.