Multidimensional Morphology of the Ethmoid Roof and Anterior Ethmoidal Artery - A CT-Based Analysis and Proposal of the Akcan Classification

Q: What problem does the study address regarding existing ethmoid roof classifications?

It addresses how widely used classifications, such as the Keros system, primarily reflect vertical depth and may not capture the complex geometric relationship between the ethmoid roof, lateral lamella, and the AEA.

Q: What does the Akcan Classification propose and how is it positioned versus the Keros system?

It proposes a descriptive radiological framework integrating AEA exit patterns with multiple morphometric measures, complementing depth-based systems like Keros rather than serving as a validated predictor of surgical outcomes.

Sep 30, 2026

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Anatomical variation in the ethmoid roof and the lateral lamella critically affects vulnerability during endoscopic sinus and skull base surgery, yet common depth-focused schemes inadequately describe their complex geometry with the anterior ethmoidal artery (AEA). Using high-resolution CT, a retrospective cohort of 175 adults (350 sides) quantified multiple morphometric parameters and AEA exit patterns, then proposed the Akcan Classification as a radiological framework. Interobserver reproducibility for measurements was excellent (ICC 0.87–0.94). Suspended AEA types showed broader ethmoid roofs, deeper lateral lamellae, steeper inclinations, and shorter AEA-lamella distances, supporting standardized preoperative anatomical assessment.

LanguageEnglish

CategoryResearch & Report

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Pages16

Reading Time40 min

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Abstract

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1. Introduction

Article Multidimensional Morphology of the Ethmoid Roof and Anterior Ethmoidal Artery: A CT-Based Analysis and Proposal of the Akcan Classification Abdullah Belada 1, *, Fatih Alper Akcan 2, Derya Güçlü 3, Ender Güçlü 1, ˙Ilhan Ünlü 1, Bu ˘gra Suba¸sı 1, Mehmet Ali Özel 3, Ethem ˙Ilhan 4, Derya Cebeci 4 and Mehmet Ali Sungur 5 Academic Editor: RamiR. Hallac Received: 10 December 2025 Revised: 23 December 2025 Accepted: 24 December 2025 Published: 25 December 2025 Copyright: © 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license. 1 Department of Otorhinolaryngology, Faculty of Medicine, Duzce University, Duzce 81620, Türkiye; [drilhan@gmail.com](drilhan@gmail.com) (˙I.Ü.); drbugrasubasi@gmail.com (B.S.) 2 Department of Otorhinolaryngology, Private Ça ˘gsu Hospital, Duzce 81600, Türkiye; [f.akcan@yahoo.com](f.akcan@yahoo.com) 3 Department of Radiology, Faculty of Medicine, Duzce University, Duzce 81620, Türkiye; [deryasr@hotmail.com](deryasr@hotmail.com) (D.G.); [drmaliozel@gmail.com](drmaliozel@gmail.com) (M.A.Ö.) 4 Department of Otorhinolaryngology, Gaziosmanpa¸sa Training and Research Hospital, University of Health Sciences, Istanbul 34255, Türkiye; [ethem.ilhan@sbu.edu.tr](ethem.ilhan@sbu.edu.tr) (E.˙I.); drderyacebeci@gmail.com (D.C.) 5 Department of Biostatistics, Faculty of Medicine, Duzce University, Duzce 81620, Türkiye; [malisungur@yahoo.com](malisungur@yahoo.com) * Correspondence: [abdullahbelada@yahoo.com](abdullahbelada@yahoo.com) Abstract Background/Objectives: Anatomical variation in the ethmoid roof and lateral lamella play an important role in anatomical vulnerability during endoscopic sinus and skull base surgery. However, widely used classifications, including the Keros system, primarily focus on vertical depth and may not fully reflect the complex geometric relationship between the ethmoid roof, lateral lamella, and the anterior ethmoidal artery (AEA) . This study aimed to characterize ethmoid roof and lateral lamella anatomy using high-resolution CT and to propose a descriptive radiological framework—the Akcan Classification—that integrates AEA exit patterns with multiple morphometric parameters. Given the complexity of thin skull base structures, interobserver reproducibility of all morphometric parameters was additionally assessed to ensure measurement robustness. Methods: High-resolution paranasal sinus CT scans from 175 adults (350 sides) were retrospectively evaluated. Measurements included ethmoid roof width, lateral lamella depth, anterior–posterior length, lamellar angle, AEA–lamella distance, and sinonasal anatomical variations. Interobserver reliability was quantified using ICCs. AEA morphology was categorized as in-canal (Type 1), partially suspended (Type 2), or fully suspended (Type 3) based on radiological appearance of bony canalization. Appropriate statistical tests were used to compare morphometric features across groups. Results: Suspended AEA configurations demonstrated progressively wider ethmoid roofs, deeper lateral lamellae, steeper lamellar inclination, and shorter AEA– lamella distances (all p < 0.001) . Supraorbital ethmoid cells were more frequently observed in Type 3 cases (p < 0.001) . Other anatomical variations showed no significant association with ethmoid roof morphology. Interobserver reliability was excellent for all measurements (ICC range 0.87–0.94) . Conclusions: The findings suggest that AEA configuration is associated with broader patterns of ethmoid roof and lateral lamella morphology. Rather than serving as a validated predictor of surgical outcomes, the Akcan Classification provides a structured anatomical and radiological descriptor that complements depth-based systems such as the Keros classification. The high reproducibility of measurements supports its potential utility for standardized anatomica

FAQs

What problem does the study address regarding existing ethmoid roof classifications?

It addresses how widely used classifications, such as the Keros system, primarily reflect vertical depth and may not capture the complex geometric relationship between the ethmoid roof, lateral lamella, and the AEA.

How were ethmoid roof and AEA features evaluated in this research?

High-resolution paranasal sinus CT scans from 175 adults (350 sides) were retrospectively analyzed, measuring multiple morphometric parameters and categorizing AEA morphology by radiological bony canalization patterns.

What does the Akcan Classification propose and how is it positioned versus the Keros system?

It proposes a descriptive radiological framework integrating AEA exit patterns with multiple morphometric measures, complementing depth-based systems like Keros rather than serving as a validated predictor of surgical outcomes.

Sep 30, 2026

Upload by Connor