Investigation of Vestibular Aqueduct in High-Resolution CT Scan in Patients with Otosclerosis

Otosclerosis is caused by abnormal bone remodeling in the middle ear, which is associated with dizziness and lightheadedness. An underlying cause of dizziness in this disease can be the presence of an enlarged vestibular aqueduct. In this study, the prevalence of enlarged vestibular aqueduct in these patients compared to the normal population has been investigated.

In this cross-sectional study, 26 people with bilateral otosclerosis and 26 people with at least one healthy ear requiring a CT scan were compared. Vestibular aqueduct was tested by evaluating the two factors of the midpoint width between the external diaphragm and the common crus, and its width in the external diaphragm region and comparing the two groups. Bone conduction, speech detection threshold, and gap between bone conduction and air conduction were calculated and compared in otosclerosis patients with enlarged versus normal vestibular duct.

The median width of the vestibular aqueduct in the area of the external aperture in patients with otosclerosis (1.2 mm) was significantly greater than that of healthy subjects (1 mm) (p=0.046). Regarding the size of the vestibular aqueduct in otosclerosis patients, 5 patients (9.6%) were found with enlarged vestibular aqueduct in radiological findings. However, this difference was not statistically significant. In otosclerosis patients, bone conduction threshold in all frequencies was significantly higher in people with enlarged vestibular aqueduct compared to other patients (p<0.001).

Based on the results of this study, the prevalence of enlarged vestibular aqueduct in patients with otosclerosis is considerable, and it is better to pay enough attention to the CT scan of patients before surgery to prevent possible complications.