Cochlear Nerve Deficiency Prevalence in Pediatric Cochlear Aperture Stenosis Patients

Introduction: Studies have shown that patients with single-sided deafness and cochlear nerve deficiency (CND) who undergo cochlear implantation (CI) receive limited benefit from implantation. Magnetic resonance imaging (MRI) has become a key imaging modality in work-up for CI, allowing for the evaluation of CND. While cochlear aperture stenosis (CAS) has been linked with CND, limited studies have investigated the exact relationship between the two. The aim of this study was to determine the prevalence of CND in pediatric patients with CAS to better inform decision making regarding the utility of MRI in this population.

Methods: In this retrospective cohort study, pediatric patients with single-sided or bilateral hearing loss with a diagnosis of CAS on CT and a temporal bone MRI that was performed between January 1, 2016 and December 31, 2022 were included. The presence or absence of CND, defined as a hypoplastic or aplastic cochlear nerve on MRI, was assessed for each included patient to determine the prevalence among CAS patients.

Results: In total, 33 patients with CAS were included. Of these, 54.5% (n=18) were male and 42.2% (n=14) had left CAS, 42.2% (n=14) had right CAS, and 15.5% (n=5) had bilateral CAS. Of included patients, 93.9% (n=31) were noted to have cochlear nerve deficiency on MRI, while determining the status of the cochlear nerve in the remaining 2 patients was limited due to poor imaging quality.

Conclusions: This study determined that pediatric patients with CAS have a high likelihood of associated CND on MRI, indicating that MRI may provide limited additional information in this population. Given the need for sedation in younger children and increased cost of MRI, careful shared decision-making should be used in determining the utility of pursing MRI in patients with diagnosed CAS on CT.