Philippine Journal of Otolaryngology Head and Neck Surgery (Jun 2008)
Radiographic Analysis of the Ethmoid Roof based on KEROS Classification among Filipinos
Abstract
Objective: The objective of the study was to describe the distribution of Keros classification among Filipinos. Methods: Study Design: Retrospective review of consecutive paranasal sinus computed tomography (PNS CT) scans. Setting and Participants: One hundred and twenty-eight consecutive PNS CT scans done at the Philippine General Hospital done from January 2006 to August 2007 were reviewed; 109 PNS CT scans were included in the study. The bilateral heights of the lateral lamellae of the cribriform plate were obtained, independently coded, and classified according to Keros classification. Results: The mean height of the lateral lamella among Filipinos was 2.21mm. One hundred sixty five cases (81.6%) were classified as Keros I. Fifty two cases (17.9%) were classified as Keros II and one (0.5%) case was classified as Keros III. There was no significant difference in the height of the lateral lamella (t-test: p=0.77, CI 95%) and the distribution of Keros classification (Fisher’s Exact test: p = 0.78) among younger (1-14 year) and older (>14 year) Filipino age groups. There was significant difference in the height (t-test: p=0.05, CI 95%) and the distribution of Keros classification (Fishers Exact Test: p=0.01) between Filipino females and males. There was no significant difference in the height of the bilateral lateral lamellae among Filipinos (paired t-test: p=0.51, CI 95%). There was no significant difference in the distribution of Keros classification (Fisher’s Exact Test: p=0.48) between the right and left lateral lamella. Conclusions: In over 80% of the time Filipinos are classified as Keros I. Risk of inadvertent intracranial entry thru the lateral lamella among Filipinos is less compared to populations with majority of cases classified as Keros II or III. Keywords: Keros classification, Filipino, Paranasal Sinus, PNS-CT, Ethmoid roof, Ethmoid anatomy
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