Radiographic Analysis of the Ethmoid Roof Anatomy Based on Keros Classification in a Cohort of Sri Lankan Population

Abstract

This is a cross sectional study that aims to describe the distribution of heights of lateral lamella of ethmoid bone according to Keros classification. All available CT scans at ENT unit, Teaching Hospital Anuradhapura were reviewed. Heights of the lateral lamellae on both sides were measured, and classified according to Keros classification. Fiftyone CT Scans were analysed. The mean height of right lateral lamella was 5.16mm (SD 1.6) and of left lateral lamella was 5.06mm (SD1.7) (No significant difference (P=0.418)). Mean height on right side in males was 5.25mm (SD 1.37), and in females was 5.06mm (p=1.96) (No significant difference (p=0.696)). Mean height on left, for males was 5.01mm (SD 1.43) and for females it was 5.11mm (SD 2.04),(No significant difference. (p=0.854)). Keros type I was seen in 12 (24%) each on both sides. Keros type II were seen in 31 (62%) on right and 32 (62%) on left. There were 7 (14%) with Keros III on right side and 6 (12%) on left side. Over 60% of Sri Lankans are likely to be in Keros II. Risk of intracranial entry during nasal surgery among Sri Lankans is likely to be similar to that of western population.