The Predictability Precision of Superior Semicircular Canal Through Radiological Assessment and Microanatomical Dissection.

OBJECTIVE: There is still ongoing research on the relationship of arcuate eminence (AE) and superior semicircular canal (SSC). We aimed to evaluate the precision of predictability of SSC through the morphology of AE via radiological means.

MATERIALS AND METHODS: This investigation is performed on 12 dry skulls belonging to Mersin University Medical Faculty department of anatomy. Computed tomography (CT) assessment is performed with 0.5-mm-thin sections temporal bone algorithm on dry skulls which were marked with fixated copper wire by scotch tapes on the most prominent part of the middle fossa floor assuming the location of AE. The data are reformatted on the workstation with vitrea 2.0. The distances of the determined three points including lateral (A), apical (B), and medial (C) of the SSC and the copper wire are measured radiologically. Also, the height between the most apical part of the SSC to the floor of the skullbase (H) is measured. The angles between the placed copper wires and the SSC (E) are calculated. The angle between SSC and the midpoint of the IAC (F) and SSC to the sulcus of the greater GSPN (G) were measured. The nearest distance was measured between the most posterior part of the SSC and the point marked by the perpendicular line drawn from the medial border of the petrous bone to the most posterior part of the internal auditory canal (IAC) (D).

RESULTS: The right and left A, B, and C distances are 2.54+/- 2.75, 3.67+/-3.16, 5.85+/-3.77; 2.92+/-2.24, 3.68+/-2.93, 6.09+/-3.40, respectively. We could not find any statistical significance when the right A, B, and C distances were compared with the left values. Examination of the values revealed that C distance is greater than the A distance of the same side both for right (p=0.040) and left (p=0.022) measurements. The calculated left and right E angles are 30.313+/-12.838, and 35.558+/-18.437 degrees, respectively. Statistical significance was not found between the right and left angles. The right and left F, G angles were 53.17, 47.25; 93.58, 100.92 degrees; and D distances are 8.01, 8.13 millimeters, respectively. Statistical significance was not found when right and left E, F, G angles and D distances were compared. Among 12 left and 12 right sides, the copper wire was found to be nearly overlapping to SSC in two in the right and only one in the left.

CONCLUSION: This study reveals that there is a great variability predicting the exact location of SSC through the prominence of AE. Complementary studies are needed with greater number of dry skulls and cadavers. Comparison of different hypothesis including the effect of temporal lobe sulcus is to be discussed to better enlighten the exact relationship of the aforementioned anatomical structures.