Relationship between Height of Ethmoid Skull Base and Length of Lateral Lamella by Sectional Coronal Computed Tomography Scan before Endoscopic Sinus Surgery.

Background: Damage to ethmoid skull base (ESB) and lateral lamella (LL) during endoscopic sinus surgery (ESS) causes penetration into the brain. This study is aimed to determine the relationship between the height of ESB and length of LL by sectional coronal computed tomography (CT) scans before ESS.

Materials and Methods: In a cross-sectional study, 100 patients admitted to ENT clinic of Al-Zahra Hospital, filled the consents regarding the use of CT scan stereotype. Each stereotype was evaluated and using the software on two sides the height of ESB and the length of LL were measured, investigated and recorded. Next, the maximum and minimum height and length in the two sides was measured, and its mean calculated. Then, the relationship between the length of LL and the height of ESB was investigated.

Results: There was a direct correlation, with the rate of 0.25 between the length of right LL and height of right ESB that was significant according to Pearson test ( P = 0.013). Also, the rate of correlation between the left LL and height of left ESB was 0.15 that was not significant according to Pearson test ( P = 0.15).

Conclusion: Based on this study there was a direct correlation between height of the right ESB and the length of LL, but this correlation is very low, about 0.25 and even this correlation was lower in the case of left, about 0.15, which both of them are not significant. This may be due to other affecting factors, such as length, slope and angle of fovea ethmoidallis from the horizontal line.