Stapes angle and facial nerve-stapes head distance in patients with otosclerosis

Objective: In this study, we aimed to compare the relationship between stapes angle, facial nerve-stapes head distance (FNSD), and densitometry in patients with otosclerosis and a control group without otosclerosis using high-resolution computed tomography (HRCT). Methods: In this retrospective study, the temporal bone CT images of patients obtained between November 2016 and January 2018 were evaluated using a dedicated workstation. The relationship between the densitometry measurements around the otic capsule, stapes angle, and FNSD were assessed and the contribution of this relationship to the diagnosis of otosclerosis was investigated. Results: The patient group was found to have lower density measured in the posterolateral to the middle turn of the cochlea than the control group (p<0.001). No statistically significant difference was found between the patient and control groups in terms of the remaining densitometry measurements. The average stapes angle was 77.72°±7.23° in the control group and 73.65°±6.38° in the patient group (p<0.001). Similarly, FNSD was found to be shorter in the patient group than in the control group (p<0.001). Conclusion: In addition to the densitometry values in HRCT, FNSD and stapes angle values can be used in the radiological diagnosis of otosclerosis. However, additional studies are needed to determine the exact reference points in stapes angle measurements.