Association Between Tegmen Tympani Status and Superior Semicircular Canal Pattern

Area of Science:

• Otolaryngology
• Anatomy
• Radiology

Background:

• The tegmen tympani (TT) is the thin bony plate separating the middle cranial fossa from the epitympanum.
• Superior semicircular canal (SSC) dehiscence is a common finding in the temporal bone, potentially leading to auditory symptoms.

Purpose of the Study:

• To investigate the association between the bony coverage of the superior semicircular canal (SSC) and the status of the tegmen tympani (TT).
• To quantify the relationship between different SSC patterns and tegmen tympani dehiscence (TTD) or integrity (TTI).

Main Methods:

• An observational study analyzing 607 temporal bones from consecutive patients using thin-section multidetector row computed axial tomography (CAT scan).
• Evaluation of SSC bone coverture thickness and TT status (dehiscence or integrity).
• Multivariate binary logistic regression was used to model the probability of TTD based on SSC pattern and age.

Main Results:

• The study identified various SSC patterns: normal (76.77%), papyraceous/thin (11.20%), dehiscence (3.79%), thick (4.94%), and pneumatized (3.29%).
• Tegmen tympani dehiscence (TTD) was observed in 10.87% of cases and was significantly associated with SSCD and papyraceous SSC patterns.
• TTI was more frequent with normal and thick SSC patterns (p=0.001).

Conclusions:

• A significant association exists between superior semicircular canal (SSC) pattern and tegmen tympani (TT) status.
• Increasing age amplifies the risk of TTD, with papyraceous and SSCD patterns showing substantially higher risks (12 and 20 times, respectively).
• These findings highlight the interplay between SSC morphology, TT integrity, and age in temporal bone anatomy.