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CC BY-NC-ND 4.0 · Int Arch Otorhinolaryngol 2023; 27(04): e565-e570
DOI: 10.1055/s-0042-1758213
Original Research

External Auditory Canal: Computed Tomography Analysis and Classification

Mohammad Waheed El-Anwar 
1   Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Medicine, Zagazig University, Zagazig, Egypt
,
Yasser Ahmed Fouad 
1   Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Medicine, Zagazig University, Zagazig, Egypt
,
Ahmed Fouad Elgohary
1   Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Medicine, Zagazig University, Zagazig, Egypt
,
Sameh Saber 
2   Department of Radiodiagnosis, Faculty of Medicine, Zagazig University, Zagazig, Egypt
,
Mohamed Adel Mobasher 
1   Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Medicine, Zagazig University, Zagazig, Egypt
› Author Affiliations Funding The authors declare no financial support or interest to this study.
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Abstract

Introduction Computed tomography (CT) details of the external auditory canal (EAC) are not fully covered in the literature, so building up base for the CT evaluation and description is important. Preoperative details of the EAC are mandatory before any approach or procedure involving the canal.

Objective To determine the different dimensions, measurements, and grading of the EAC by CT scan that were not previously published.

Methods The CT scans of 100 temporal bones (200 sides) were included. Axial images were acquired with multiplanar reformates to obtain delicate details in coronal and sagittal planes for all subjects.

Results At the EAC entry, the mean vertical length (height) was 7.75 ± 1 mm, and its mean horizontal length (width) was 6.1 ± 0.8. At the bony cartilaginous junction of the EAC, the mean vertical length was 7.88 ± 1 mm, and its mean horizontal length was 6.22 ± 0.9. At the EAC isthmus, the mean vertical length was 6.8 ± 0.97 mm, and its mean horizontal length was 5.2 ± 0.76. At the medial end of the EAC, the mean vertical length was 7.1 ± 0.9 mm, and its mean horizontal length was 5.4 ± 0.85. There were no reported significant differences between right and left sides in all dimensions. Males showed significantly longer vertical and horizontal dimensions of the EAC entry, vertical dimension of the isthmus, and vertical dimension of the medial end of the EAC than females.

Conclusion This study improves otologists and radiologists' awareness of EAC variations in the ear field and can be of help to residents in training.

Keywords

external auditory canal - ear - computed tomography - isthmus - endoscopic ear surgery

Ethics Approval and Consent to Participate

A written informed consent was obtained from the study participants, and Zagazig University IRB approved the study proposal (IRB 117–1-18).


Availability of Data and Materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.


Authors' Contributions

MWE: Modified the idea, reviewed the literature, conceptualization and design of the study, revised CT evaluation, did statistical analysis, interpreted the data, tabulated the interpreted data, wrote and revised the article, and contributed to the approved the final manuscript to be published; YAF: Suggested and developed the idea, analyzed the data, assisted in writing the manuscript, revised the article, and contributed to the final approval of the article. AFE: Reviewed the literature, contributed to the data interpretation, revised the manuscript, and contributed to the final approval of the article. SS: Made the CT, measured the CT images, recorded patients' data, revised the methodology, prepared figures, revised manuscript, and contributed to the final approval of the article. MAM: Reviewed the literature, assisted in taking the measurements, collected and tabulated the data, contributed to the data interpretation, assisted in preparing figures, and contributed to the final approval of the article.


All authors have read and approved the manuscript.




Publication History

Received: 31 May 2022

Accepted: 30 June 2022

Article published online:
19 September 2023

© 2023. Fundação Otorrinolaringologia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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