Arcuate eminence distance to temporal bone outer table in the middle fossa repair of superior canal dehiscence

Abstract

Purpose To investigate the influence of arcuate eminence’s distance to temporal bone outer table (AE-OT) on surgical outcomes following the middle fossa repair of superior canal dehiscence (SCD). Methods We conducted a cohort study of consecutive repairs at a center between 2011 and 2022. AE-OT was measured on temporal bone CT imaging. Surgical outcomes were assessed with established metrics including Symptom Resolution Score (SRS), rate of Overall Symptom Improvement (OSI), and change in low-frequency air–bone gap (ΔLF-ABG) from pre- to post-surgery. Multivariable regression models assessing surgical outcomes were constructed with AE-OT as the primary predictor. Models adjusted for patient demographics, medical and surgical history, and follow-up duration. Results A total of 402 repairs were included. Mean AE-OT was 27.1 mm (SD 2.1, range 20.8–33.9). Every mm increase in AE-OT was independently associated with a 14% reduction in odds of OSI (aOR 0.86, 95% C.I. [0.75, 0.98]) and a 4-point decrease in SRS (adj. β − 4.0 [− 6.9, − 1.1]) among frank dehiscences. AE-OT was also not associated with operative duration and ΔLF-ABG among both frank dehiscences and near dehiscences. Conclusions Longer AE-OT predicted poorer symptomatic response but similar operative duration and audiometric improvement among frank SCD cases.