Major and minor temporal bone abnormalities in children with and without congenital sensorineural hearing loss.

OBJECTIVE: To determine the extent of correlation between sensorineural hearing loss (SNHL) and abnormal temporal bone anatomy in children.

DESIGN: Axial and coronal high-resolution computed tomographic scans of the temporal bones of 247 children (494 ears) aged 2 months to 15 years with and without SNHL were blindly reviewed. The presence or absence of mild or severe cochlear dysplasias, vestibular dysplasias, and an enlarged vestibular aqueduct (VA) were recorded. The width of the VA was measured. The height, width, and length of the internal auditory canal (IAC) were measured, and abnormalities were described as narrow, widened, or bulbous. Clinical information was then reviewed to determine the presence or absence of a congenital syndrome and/or SNHL, and historical factors that might be responsible for SNHL.

MAIN OUTCOME MEASURE: The relationship between radiographic findings and SNHL.

RESULTS: One hundred thirteen patients (185 ears) had SNHL. Significant abnormal temporal bone anatomy in children with vs without SNHL included major cochlear and vestibular dysplasias (17% vs 0%; P<.001), enlarged VA (>2 mm) (5% vs 0%; P<.001), and narrow IAC (< or =2 mm) (4% vs 1%; P=.03). The average IAC width (4.85 vs 5.02 mm), height (4.39 vs 4.62 mm), and length (11.22 vs 11.44 mm) were not statistically different between children with vs without SNHL. In children with vs without SNHL, neither a widened (0.5% vs 3.6%) nor a bulbous (9% vs 8%) IAC was seen more often in children with SNHL. In ears with SNHL, the presence of a congenital syndrome significantly increased the risk of cochlear and vestibular abnormalities of the temporal bone (45% vs 14%; P<.001), including IAC abnormalities (30% vs 2%;P<.001), which overall were more commonly seen in children with (20%) vs without (3%) a congenital syndrome regardless of the presence of SNHL. No children with an enlarged VA had a congenital syndrome.

CONCLUSIONS: Well-established temporal bone abnormalities such as cochlear and vestibular abnormalities and a grossly enlarged vestibular aqueduct are significantly found in children with SNHL. A narrow IAC is found more often in children with vs without SNHL. No significant correlation is found between SNHL and radiographic findings of a widened or bulbous IAC. In children with a congenital syndrome, more IAC abnormalities were seen, regardless of the presence of SNHL. In children with SNHL, the presence of a congenital syndrome increases the likelihood of a cochlear or vestibular abnormality.