Congenital perilymphatic fistula and associated middle ear abnormalities.

To specifically determine the frequency and type of middle ear abnormalities associated with perilymphatic fistula (PLF), a retrospective chart review was performed of 94 patients (117 ears) who underwent exploratory tympanotomy for PLF from 1980 to 1989. Of the 117 ears explored, 80 (68.4%) had a PLF, and in 65 (81.3%) of these ears, a middle ear malformation was associated with the PLF. Of these 65 ears in which a congenital middle ear abnormality was observed, a malformed stapes was the most common abnormality seen (39 ears, 60%), followed by a deformed round window (20 ears, 30.8%), a deformed incus (11 ears, 16.9%), and a deformed promontory (2 ears, 3%). Often these malformations coexisted amongst themselves or with inner ear abnormalities. Sixteen children (25 ears) had an inner ear malformation identified on computed tomography (CT); all of these children had a PLF found at the time of surgery. This study demonstrated that 86.3% of the ears found to have a PLF had a deformity of the middle ear, inner ear, or both. A malformation of the stapes, most frequently identified as a deformity of its superstructure (and presumably also the anterior footplate), was the most common congenital middle ear abnormality found to be associated with PLF in children.