Radiological Configuration of the Vestibular Aqueduct Predicts Bilateral Progression in Meniere's Disease.

Objective

Meniere's disease (MD) progresses from unilateral to bilateral disease in up to 50% of patients, often chronically and severely impairing balance and hearing functions. According to previous studies, 91% of bilateral MD patients demonstrate bilateral hypoplasia of the endolymphatic sac (ES) upon histological and radiological examination of their inner ears. Here, we seek to validate a radiological marker for ES hypoplasia that predicts the risk for future progression to bilateral MD in individual patients.

Methods

Patients with unilateral MD and radiological evidence for ES hypoplasia in either the clinically affected inner ear (cohort MDuni-hpuni) or both inner ears (cohort MDuni-hpbi) were included. Given our hypothesis that ES hypoplasia critically predisposes the inner ear to MD, we expected progression to bilateral MD only in the MDuni-hpbi cohort. To investigate eventual progression to bilateral MD, clinical, audiometric, and imaging data were retrospectively collected over follow-up periods of up to 31 years.

Results

A total of 44 patients were included in the MD-hpuni (n = 15) and MDuni-hpbi (n = 29) cohorts. In line with our radiology-based predictions, none (0/15) of the MD-hpuni patients exhibited progression to bilateral MD, whereas 20/29 (69%) MD-hpbi patients have already progressed to bilateral MD. Using the Kaplan-Meier estimator, bilateral disease progression would be observed in 100% of MD-hpbi patients 31 years after the initial diagnosis with an estimated median time to bilateral progression of 12 years. The nine MD-hpbi patients who, so far, remained with unilateral disease demonstrated a median time since initial (unilateral) MD diagnosis of only 6 years and are thus still expected to progress to bilateral disease.

Conclusion

Progression to bilateral MD adheres to predictions based on the radiological presence or absence of ES hypoplasia. This prognostic tool, if validated by prospective long-term studies, will provide clinically relevant information about a patient's future disease burden and will help to select more personalized treatment regimens.