High Prevalence of Cochlear Nerve Deficiency in Pediatric Patients With Cochlear Aperture Stenosis.

Objective: Cochlear nerve deficiency (CND) is a common radiologic finding among unilateral sensorineural hearing loss (USNHL) patients. It is generally detected with magnetic resonance imaging (MRI), which is associated with higher cost, less availability, and possible need for sedation. Therefore, identifying computed tomography (CT) findings, such as cochlear aperture stenosis (CAS), that can reliably predict CND is valuable. Our study aimed to determine the prevalence of CND in pediatric patients with CT-diagnosed CAS.

Study Design: Retrospective study.

Setting: Tertiary care center.

Methods: We included pediatric patients diagnosed with CAS on temporal bone CT and with available temporal bone MRI. For each patient, an otolaryngologist and a pediatric neuroradiologist measured the cochlear aperture width on CT to confirm CAS (cochlear aperture < 1.4 mm) and assessed the status of the cochlear nerve on MRI.

Results: Fifty-five patients, representing 65 ears, had CAS on CT measurement. Median cochlear aperture width in CAS ears was 0.70 mm (interquartile range [IQR]: 0.40-1.05 mm) versus 2.00 mm in non-CAS ears (IQR: 1.80-2.30 mm, P < .001). CND was found in 98.5% (n = 64/65) of CAS ears, while a normal cochlear nerve was found in 1.5% (n = 1/65) of CAS ears.

Conclusion: CND is highly prevalent among pediatric patients with CAS. This suggests that MRI may not be needed to assess for CND in USNHL patients with CAS, as initial CT may provide sufficient information to determine cochlear implant candidacy. We recommend thoughtful shared decision-making with parents of USNHL patients when determining whether to pursue MRI in the setting of a CAS diagnosis.