Vestibular Aqueduct Hypoplasia Identifies Semicircular Canal Dehiscence Patients Who Progress to Meniere’s Disease

Objective: Semicircular canal dehiscence (SCD) and vestibular aqueduct (VA) hypoplasia are developmental anomalies associated with distinct inner ear syndromes—SCD syndrome and Meniere’s disease (MD). Our previous work found frequent SCD in MD patients with VA hypoplasia, suggesting a shared developmental origin. To further explore this association, we adopted a reciprocal approach by assessing VA hypoplasia prevalence in patients diagnosed with SCD. Study Design: Retrospective cohort study. Setting: Tertiary referral center. Patients: A total of 219 ears from 173 patients (mean age 53.5 years, standard deviation 16.6 years; 54.3% females) were evaluated for suspected SCD, confirmed by temporal bone computed tomography (CT). Interventions: Radiological analysis of temporal bone CT scans using the angular trajectory of the vestibular aqueduct (ATVA) marker; review of clinical records for diagnosis of MD. Main Outcome Measures: Prevalence of VA hypoplasia among SCD patients; association of radiological findings with clinical diagnosis of MD. Results: VA hypoplasia was identified in 4 of 173 patients (2.3%), representing a 46-fold increase compared with the estimated 0.05% prevalence of MD patients with VA hypoplasia in the general population. These cases showed an atypical SCD localization in the posterior limb of the superior semicircular canal. All 4 patients were diagnosed with MD ipsilateral to the SCD/VA hypoplasia. Conclusions: SCD and VA hypoplasia are associated in a distinct patient group, suggesting a shared developmental etiology. These patients may be predisposed to an early overlap of SCD syndrome and MD, with their clinical course eventually dominated by the progressive nature of MD.