Cochlear clefts in children: prevalence, characteristics, and clinical implications

Temporal bone computed tomography (CT) is essential for evaluating ear diseases but requires awareness of normal variations to avoid misdiagnosis. The cochlear cleft, seen as pericochlear CT hypoattenuation, reflects incomplete endochondral ossification and mainly occurs in children. Although a normal variant, it can mimic conditions such as otosclerosis. Data on its prevalence and extent in children, especially in relation to hearing status and other temporal bone findings, remain limited.

The aim of our study is to evaluate the overall prevalence of cochlear clefts in children and to determine their clinical significance.

A total of 404 temporal bone CTs without pathologies were reviewed retrospectively by two neuroradiologists. The prevalence and the extent (mild, moderate, or extensive) of pericochlear CT hypoattenuation, representing the cochlear cleft, were recorded, and their correlation with clinical findings was evaluated.

Among 404 CTs examined, cochlear clefts were observed in 135 cases (33.4%). The presence of cochlear clefts was independently associated with a younger age group (0-4 years old, P-value <0.001), but not with other parameters such as sex, hearing loss status, inner ear anomalies, or other temporal bone pathologies.

Cochlear clefts are an anatomical variation that is prevalently associated with younger age. Thus, pericochlear CT hypoattenuation in young children should be interpreted with caution, as it can be caused either by cochlear clefts (an anatomical variation) or by pathologies. Radiologists should be aware of and recognize cochlear clefts to avoid unnecessary medical or surgical interventions.