Prevalence of Jugular Bulb Abnormalities and Resultant Inner Ear Dehiscence: A Histopathologic and Radiologic Study

Objective. Jugular bulb abnormalities (JBA), including high-riding jugular bulb (HRJB) and jugular bulb diverticulum (JBD), can erode into the inner ear. In this study, the authors investigate the prevalence and consequences of JBA and their erosion into inner ear structures using temporal bone histopathology and computed tomography (CT). Study Design. Cross-sectional study of temporal bone histopathology and radiology. Setting. Academic medical center. Subjects and Methods. In total, 1579 temporal bone specimens and 100 CT of the temporal bones (200 ears) were examined for JBA and any associated dehiscence of inner ear structures. Temporal bone specimens were examined for histological consequences of inner ear erosion. Jugular bulb dimensions were measured on axial CT scans and compared across groups. Accompanying demographic and clinical information were reviewed. Results. High jugular bulbs were noted in 8.2% (130/1579) of temporal bone specimens and in 8.5% (17/200) of temporal bone CT. The prevalence of JBA increases during the first 4 decades of life and stabilizes thereafter. High-riding jugular bulbs eroded inner ear structures such as the vestibular aqueduct, vertical facial nerve, or posterior semicircular canal in 2.8% (44/1579) of cases histologically and 1.5% (3/200) radiologically. In most, jugular bulb-mediated inner ear dehiscence was clinically and radiologically silent. Conclusion. Jugular bulb abnormalities are common. They are present in 10% to 15% individuals and are primarily acquired by the fourth decade of life. In 1% to 3% of cases, the HRJB erodes into the inner ear and most frequently involves the vestibular aqueduct.