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Discovering Middle Ear Anatomy by Transcanal Endoscopic Ear Surgery: A Dissection Manual
Published on: January 11, 2018
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Classification of the Chorda Tympani: An Endoscopic Study
Tsukasa Uranaka1, Yu Matsumoto1, Yujiro Hoshi1
1Department of Otolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Summary
Preoperative CT scans can predict the external auditory canal type of the chorda tympani nerve (CTN). Other CTN anatomical variations can be predicted by grouping them, aiding surgical planning in endoscopic ear surgery.
Area of Science:
- Otolaryngology
- Neurosurgery
- Medical Imaging
Background:
- The chorda tympani nerve (CTN) exhibits variable anatomy, impacting surgical procedures.
- Accurate preoperative assessment of CTN anatomy is crucial for successful endoscopic ear surgery.
Purpose of the Study:
- To evaluate the accuracy of preoperative computed tomography (CT) in predicting the surgical anatomy of the chorda tympani nerve (CTN).
- To classify CTN anatomy based on endoscopic tympanotomy findings.
Main Methods:
- Retrospective review of 128 ears from 101 patients who underwent transcanal endoscopic ear surgery.
- Classification of intraoperative endoscopic images of the CTN into five types: external auditory canal (EAC), detached, attached long, attached short, and ultrashort.
- Analysis of preoperative CT scans to correlate with endoscopic classifications.
Main Results:
- Five CTN types were identified: EAC (5.5%), detached (4.7%), attached long (65.6%), attached short (14.0%), and ultrashort (10.2%).
- Preoperative CT accurately predicted the EAC type.
- Other CTN types were predictable when grouped, with a sensitivity of 0.61 and specificity of 0.72.
Conclusions:
- The variable anatomy of the chorda tympani nerve can be classified into five distinct types during endoscopic tympanotomy.
- Preoperative CT has a role in predicting CTN anatomy, particularly the EAC type, aiding surgical planning.
