Cochlear duct length variability in prelingual sensorineural hearing loss: Emphasis on Waardenburg syndrome and implications for cochlear implantation

To explore the association between cochlear duct length (CDL) and hearing loss etiologies, and evaluate its impact on cochlear implantation (CI) planning. We conducted a retrospective study on 610 patients (825 ears) who underwent CI at a tertiary center, to identify the etiologies associated with reduced CDL and investigate their influence on electrode selection and surgical outcomes. Patients diagnosed with cochlear nerve deficiency, Waardenburg syndrome (WS) associated with SOX10 variants, enlarged vestibular aqueduct syndrome, and incomplete partition type III exhibited significantly reduced CDL. Of these, WS associated with SOX10 variants exhibited the highest decrease in CDL, often with vestibular malformations. Short CDL poses surgical challenges, necessitating tailored electrode selection for optimal CI outcomes. In SOX10-related WS cases, preoperative imaging and genetic testing can aid in the early detection of the disease, enabling appropriate CI planning. These findings indicate the importance of having a preliminary estimation of CDL based on etiology and the significance of this study.