Degeneration rather than hypoplasia may be the pathologic feature of the endolymphatic sac in patients with ipsilateral delayed endolymphatic hydrops

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Objective Delayed endolymphatic hydrops (DEH) and Ménière’s disease (MD) are both hydropic ear disease. In MD patients, the endotypes of MD are classified based on pathological types of the endolymphatic sac (ES), which can be distinguished by a radiological indicator: the angular trajectory of the vestibular aqueduct (ATVA). Studies have exhibited that MD patients of different pathological types of ES manifest different clinical characteristics. Here, we aimed to investigate the prevalence of each ATVA category in DEH and MD, and to further explore the clinical significance of ATVA in ipsilateral DEH patients. Methods Twenty-seven ipsilateral DEH patients, 114 unilateral MD patients and 45 control participants were enrolled in the present study. The ATVA was determined using temporal bone CT imaging. Clinical features, including gender, age and the caloric test results, were collected. The prevalence of ATVA categories were compared between patients with ipsilateral DEH and unilateral MD. The association between ATVA and clinical features was also examined. Results (1) Compared to MD-affected ears, ATVA ≤ 120° was more frequent (χ 2 = 9.231, p = 0.002), whereas ATVA ≥ 140° was less frequent in DEH-affected ears (χ 2 = 6.865, p = 0.009). (2) Compared to control ears, the distribution of ATVA categories in affected ears of ipsilateral DEH patients was not significantly different (χ 2 = 1.190, p = 0.510). (3) The prevalence of ATVA ≥ 140°, 120° < ATVA < 140° and ATVA ≤ 120° in affected ears of ipsilateral DEH patients was comparable to that in non-affected ears (χ 2 = 1.083, p = 0.568). Conclusion Compared to unilateral MD patients, degenerative ES may be the dominant pathological type in ipsilateral DEH patients due to the high occurrence of ATVA ≤ 120°.