Radiographic Estimation of Superior Canal Dehiscence Area and Surgical Outcomes Following the Middle Fossa Approach

Introduction: Computed tomography (CT) imaging of the temporal bone constitutes an integral element in the diagnostic workup of superior canal dehiscence (SCD). This study explores the utility of a clinically efficient approximation method of SCD area in predicting surgical outcomes following the middle cranial fossa (MCF) approach.

Methods: Consecutive MCF repairs of SCD for frank dehiscence cases between 2011 and 2022 were included. Diagnostic criteria of SCD adhered to the Barany society consensus guidelines.[1] Preoperative CT imaging of the temporal bone was reviewed for determination of the approximate dehiscence area (ADA), a previously developed metric estimating the radiographic two-dimensional area of SCD.[2] Symptomatic outcomes were evaluated with two previously developed measures, symptom resolution score (SRS) and rate of overall symptom improvement (OSI).[3] Multivariable logistic regression assessing OSI and bootstrapped linear regression assessing SRS were performed with ADA as the primary predictor. All models controlled for patient age, sex, dehiscence location, prior surgery of the affected ear, and follow-up duration. Stratified analyses for cases with unilateral SCD disease and cases with bilateral SCD disease were performed.

Results: Among 321 repairs included, 43% were performed on unilateral SCD cases and 57% were performed on bilateral SCD cases. Average age was 51 years and 62% of repairs were performed on females. Mean ADA was 2.68 mm² (SD: 1.46; range: 0.36–9.12), mean SRS was 38 points (± 50 SD), and 71% of cases achieved OSI. Among unilateral SCD cases, every 1 mm² increase in ADA was independently associated with a nearly 50% reduction in odds of OSI (aOR: 0.54, 95% CI: 0.36–0.83, p = 0.005) and a 6-point decrease in SRS (adj. β: −6.5, 95% CI: −12.8 to −0.2, p = 0.04). However, ADA was not significantly associated with the rate of OSI (aOR: 0.89, 95% CI: 0.64–1.22, p = 0.46) and SRS (adj. β: 0.6, 95% CI: −5.6 to 6.7, p = 0.86) among bilateral SCD cases.

Conclusion: ADA is an efficient and practical approximation method of SCD size and showed clinical utility in predicting surgical outcomes. Employing the largest database of SCD repairs to date, our analysis demonstrated that greater ADA on preoperative CT of the temporal bone was associated with poorer symptomatic response among patients with unilateral SCD.

Publikationsverlauf

Artikel online veröffentlicht:
05. Februar 2024

• References

• 1 Ward BK, van de Berg R, van Rompaey V. et al. Superior semicircular canal dehiscence syndrome: diagnostic criteria consensus document of the committee for the classification of vestibular disorders of the Bárány Society. J Vestib Res 2021; 31 (03) 131-141 PubMed
• 2 Yang HH, Patel VS, Yang I, Gopen QS. Computed tomography approximated superior semicircular canal dehiscence size and location and their association with clinical presentation. J Clin Neurosci 2023; 112: 30-37 PubMed
• 3 Yang HH, Patel VS, Yang I, Gopen QS. Low-lying tegmen and surgical outcomes following the middle cranial fossa repair of superior canal dehiscence. Otolaryngol Head Neck Surg 2023; 170: 195-203 PubMed