Frequency of congenital inner ear malformations among cochlear implant candidates at a tertiary care Hospital, Pakistan

Objective: To determine the frequency and factors associated with congenital inner ear anomalies among cochlear implant candidates. Method: The cross-sectional study was conducted at the Department of Otolaryngology, Aga Khan University Hospital, Karachi, from October 2021 to March 2022, and comprised patients of either gender aged <18 years who received cochlear implants. All subjects underwent computed tomography and magnetic resonance imaging of the temporal bone to identify any inner ear anomaly. The data gathered included implantation age, gender, computed tomography and magnetic resonance imaging findings, and history of congenital anomaly, neurodevelopmental disorder, family hearing loss, consanguinity and brain-evoked response auditory result. Data was analysed using SPSS 23. Results: Of the 120 patients, 66(55%) were females and 54(45%) were males. The median age of the patients was 3 years (interquartile range: 2-5 years). Of the total, 7(5.8%) patients presented with inner ear malformations; 3(2.5%) each with enlarged vestibular aqueduct, Mondini malformation type II, and 1(0.8%) with semi-circular canal dysplasia. Conclusion: The frequency of inner ear anomalies amongst cochlear implant candidates was 5.8%, and the most common anomalies were enlarged vestibular aqueduct and Mondini malformation type II.