Evaluation of Superior Semicircular Canal Morphology and Its Relationship with Glenoid Fossa Roof Thickness Using Cone Beam Computed Tomography

Abstract

Purpose. This study aimed to evaluate the bone thickness of the superior semicircular canal (SSC) roof and its relationship with the roof thickness of the glenoid fossa (RGF). Methods. The cone beam computed tomography (CBCT) images of 280 patients (560 temporal regions) were surveyed. The lowest thickness of the SSC roof was measured and categorized based on the radiological patterns of the Cisneros et al. classification. The thickness of GF and the presence of dehiscence in this part were determined, as well. The relationship between the thickness of the GF roof and the bone thickness covering the SSC was also assessed. Results. The mean thickness of the SSC roof was 0.93 ± 0.48 mm, with no significant difference among different age groups and genders ( p > 0.05 ). However, superior semicircular canal dehiscence (SSCD) was more prevalent among females over 45 years old. Similarly, the individuals with the dehiscence of the GF roof had a 12.93-fold higher chance of SSCD development. Conclusions. The results indicated that the thickness of the bone overlying the SSC was significantly related to the roof thickness of the GF. However, an increase in age resulted in no significant change in the bone thickness of the SSC roof. Gender also had no role in changing the thickness of the bone overlying the SSC. Considering the decrease in the thickness of the SSC roof among females over 45 years of age, menopause may be responsible for this occurrence as well as for the increase in the prevalence of SSCD.

Patient Sex Mediates the Influence of Patient Age on Superior Canal Dehiscence Repair Outcome

“…More specifically, a 2012 review of 582 ears found that the association between aging and osteopenia of the SSC roof is especially pronounced among menopausal women, as women over 45 years old were found to have thinner SSC roof compared to women under 45 years old, but men over 45 years old were found to have similar SSC roof thickness compared to men under 45 years old 11 . Most recently, a 2022 investigation found females over 45 years old to be 3.79 times more likely to have radiographic SCD than females under 45 years old, but such finding did not apply to males 12 …”

“…11 Most recently, a 2022 investigation found females over 45 years old to be 3.79 times more likely to have radiographic SCD than females under 45 years old, but such finding did not apply to males. 12 Older women are at higher risk for osteoporosis due to reduced estrogen levels. 27 Given the association of older age and female sex with thinning of the SCD roof, researchers have hypothesized that osteoporosis/ osteopenia may be involved in the etiology of acquired SCD.…”

“…6 If any difference in surgical outcome was related to osteopenia, we would expect age to be substantially more important among female patients than among male patients. 11,12 Yet, no study to our knowledge has explored how age differentially influences surgical outcomes among females versus among males. We fill this paucity of knowledge with a retrospective analysis of over 400 SCD repairs at an institution over the past decade.…”

“…The largest analysis to date was a 2019 systematic review inclusive of 174 patients from 18 retrospective studies, which found a statistically non‐significant trend of lower symptom resolution rate among individuals over 65 compared to individuals under 65 6 . If any difference in surgical outcome was related to osteopenia, we would expect age to be substantially more important among female patients than among male patients 11,12 . Yet, no study to our knowledge has explored how age differentially influences surgical outcomes among females versus among males.…”