Superior Semicircular Canal Dehiscence (SSCD) is a recently-defined developmental defect may be associated with several craniofacial anomalies such as Cleft Lip/Palate (CLP). The present study aimed to compare subjects with unilateral and bilateral CLP and normal controls in terms of Superior Semicircular Canal (SSC) bone thickness and pattern.
A total of 238 Cone Beam Computed Tomography (CBCT) images were collected from 52 unilateral Cleft Lip and Palate (UCLP) subjects (104 temporal bones) and 38 Bilateral Cleft Lip and Palate (BCLP) (76 temporal bones) subjects and 148 healthy controls (296 temporal bones). The SSC bone thickness was measured twice and validated by a maxillofacial radiologist. The samples were then classified into five categories based on bone thickness: papyraceous or thin, normal, thick, pneumatized, and dehiscence. After all, the UCLP, BCLP, and normal control groups were compared concerning the SSC pattern and thickness.
The results revealed no significant difference among the three groups regarding the SSC pattern and thickness based on gender. The SSC patterns (P value = .001) and SSC thickness (0.01) were strongly correlated to the cleft type. The thinnest bone thickness and the highest incidence of SSCD were observed among the subjects with BCLP.
The results showed a significant association between the SSC patterns and SSC thickness and the study groups.

OBJECTIVE: We examined the anatomic features of the top of the superior semicircular canal (SSC) to help guide the surgeon considering resurfacing or plugging of an associated dehiscence, thorough the transmastoid (TM) approach.
METHODS: 19 selected cadaveric temporal bones, which had no supralabyrinthine tract, were dissected, and distances between the SSC and various structures within the temporal bone were measured with a, fine caliper.
RESULTS: The average distances from the sino-dural angle, horizontal canal top, and subacurate artery, to the top of the SSC were 31.1, 7.8, and 3.9 mm, within a small range. 7 (36.8%) out of 19 bones with a, low hanging tegmen needed a wide exposure and elevation of the dura to access the SSC top.
CONCLUSIONS: Knowledge of the anatomical details associated with the SSC from this study may help to, access the SCC dehiscence safely for resurfacing surgery via a TM approach.