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Virtual Endoscopy to Plan Transtympanic Approach to Labyrinthine Windows
Caroline Guigou1, Florian Bardin, Walid Sobhy Afifi
1*Department of Otolaryngology-Head and Neck Surgery, Dijon University Hospital; †Electronic, Imaging and Computer Science Research Laboratory, CNRS, Burgundy University; and ‡Department of Radiology, Dijon University Hospital, Dijon; and §Department of Preclinical Imaging, Biophysics, Nuclear Medicine, Strasbourg University Hospital, Strasbourg, France.
Virtual endoscopy using CT scans can assess labyrinthine window accessibility via the external auditory canal (EAC). This aids in planning minimally invasive otologic surgeries like cochlear implantation.
Area of Science:
- Otolaryngology
- Medical Imaging
- Surgical Planning
Background:
- Evaluating the labyrinthine windows (oval window [OW] and round window [RW]) is crucial for otologic procedures.
- Traditional methods may have limitations in visualizing these structures through the external auditory canal (EAC).
Purpose of the Study:
- To assess the position and accessibility of the OW and RW via the EAC using virtual endoscopy.
- To determine the utility of virtual endoscopy in pre-operative planning for transcanal otologic surgeries.
Main Methods:
- A prospective cross-sectional study involving 63 high-resolution temporal bone CT scans from 34 adult patients.
- Virtual endoscopy was performed using Osirix software, with the endoscope constrained within the EAC.
- The accessibility and optimal viewing angles of the OW and RW were analyzed on multiplanar reconstruction views.
Main Results:
- The round window (RW) was accessible in 87% of cases.
- Oval window (OW) accessibility varied, with the entire posterior crus visible in 44% of cases.
- Coronal plane views showed low interindividual variability in optimal endoscope positioning for both windows.
Conclusions:
- Virtual endoscopy through the EAC is a viable method for evaluating OW and RW accessibility.
- This technique can aid in pre-planning minimally invasive procedures, such as cochlear implantation, via a transcanal approach.
