Malformations of the inner auditory canal.

Malformations of the internal auditory meatus (I.A.M.) are often accompanied by other radiological abnormalities affecting the entire inner ear. In our series of cases we demonstrate solitary deformities of the IAM ranging from the stenosis of the canal (4 cases) to extreme narrowing (2 cases) or complete atresia. Another anomaly is the presence of a thick bony wall dividing the canal in two separate compartments, superior and inferior (3 cases). Most of the cases of solitary malformations were unilateral; they can be diagnosed at any age, considering that the patient has normal hearing in the opposite ear. When the malformation of the IAM occurs, associated with major deformities of the labyrinth (5 cases), we found an abnormal communication of CSF to the tympanic cavity, due to a severe anomaly of the fundus of the IAM. Meningitis is a frequent complication in patients with this abnormality.