Evaluation of the Relationship between Extent of Superior Semicircular Canal Dehiscence with Clinical Symptoms

Background: Superior semicircular canal dehiscence (SSCD) is an osseous defect of the arcuate eminence of the petrosal temporal bone. Patients can present with debilitating auditory and vestibular symptoms, such as hearing loss and vertigo, and may require surgical repair.

Methods: Our laboratory previously described a novel method of quantifying the size of SSCD via manual segmentation. High-resolution computed tomography (CT) images of the temporal bones were imported into a specialized segmentation software, ITK-SNAP (version 3.6.0). The volume of the dehiscence was outlined on all slices of the coronal and axial planes via a single-pixel-thick paintbrush tool, and was calculated according to the number of nonzero image voxels.

Results: A total of 104 patients were included, with a combined 143 SSCD. There were 66 females and 38 males. The average age of the patients was 55 years (range: 24–87 years). Mean postsurgical follow-up time was 119 days (range: 1–927 days). The average dehiscent volume was 1.28 mm³. The most common preoperative symptom was tinnitus (n = 85), while the most common postoperative symptom was dizziness (n = 45). SSCD volume was significantly correlated with preoperative disequilibrium (p = 0.05) via Welch two-sample t-test.

Conclusion: Advances in imaging techniques have allowed increased visualization of SSCD. The ability to correlate the volume of a dehiscence with clinical variables can improve clinical management, but further research is necessary to evaluate this possible relationship.