The Prevalence of High-Riding Jugular Bulb in Patients with Endolymphatic Hydrops
Background: High riding jugular bulb is a known anatomic variation in 6–20% of the population, with inner ear dehiscence occurring in 3–11% of patients. Occasionally inner ear dehiscence has been noted in patients with symptoms of endolymphatic hydrops. In this study the authors sought to determine the prevalence of HRJB in the endolymphatic hydrops population.
Methods: This was a retrospective chart and radiology review of patients seen at a tertiary care medical center. Patients were identified using the ICD-9 code 386.xx (Meniere's Disease - unspecified). The charts were then reviewed and patients who were considered to have a possibility of carrying the diagnosis of endolymphatic hydrops were included in the study. Patients were excluded if their primary condition was considered to be related to other conditions. All patients were required to have undergone a brain imaging study that included views of the jugular bulb available for review. CT and MRI scans of any type were included. Basic demographics, audiologic data, and electrocochleography results were recorded. A radiologist then evaluated all of the imaging studies for evidence of HRJB or inner ear dehiscence with the HRJB.
Results: The prevalence of a HRJB in all endolymphatic hydrops patients was 8.97% (7/78), and 4.49% (7/156) in all ears. The prevalence of HRJB ipsilateral to an ear with endolymphatic hydrops was 4.55% (4/88 ears) and 4.41% (3/68 ears) in ears without endolymphatic hydrops. The incidence of inner ear dehiscence with high riding jugular bulb was 1.28% (1/78), and was present in an ear with endolyphatic hydrops. All HRJBs in this study were right-sided, and right-sided jugular bulb dominance was found in 74% of patients.
Discussion: To our knowledge this is the largest series of patients with endolymphatic hydrops and imaging studies analyzed for the presence of a high riding jugular bulb. Our results suggest that a small subset of endolymphatic hydrops patients have a HRJB. The prevalence of HRJB in this population was 8.97%, similar to the previously reported prevalence in the general population. The prevalence ipsilateral to an ear with endolyphatic hydrops was 4.55% and 4.41% in ears without endolyphatic hydrops. The prevalence of inner ear dehiscence was 1.28%, which was also similar to prior reports. Overall, these results suggest that HRJB does not play a major role in classical endolymphatic hydrops, although it may play a role in a few isolated patients.