Objective evaluation, using computed tomography, of round window access for cochlear implantation

Area of Science:

• Otolaryngology
• Neurosurgery
• Medical Imaging

Background:

• Cochlear implantation relies on precise surgical access to the round window.
• Assessing round window accessibility pre-operatively is crucial for surgical planning and electrode selection.

Purpose of the Study:

• To determine optimal radiological parameters for evaluating the round window approach in cochlear implantation.
• To correlate radiological measurements with intra-operative surgical access and visibility.

Main Methods:

• Retrospective analysis of computed tomography (CT) images from 52 patients undergoing cochlear implantation.
• Evaluation of eight radiological parameters, including seven from literature and one novel parameter.
• Intra-operative clinical assessment of round window visibility (1-5 scale).

Main Results:

• Computed tomography images of 57 ears were analyzed.
• Round window visibility was rated 5 in 69% of patients after bone overhang removal.
• Statistically significant correlations were found between round window access and specific radiological parameters (Chen_Angle, RWM_prediction, Sarafraz_OH, Mehanna_OH).

Conclusions:

• Radiological measurements, particularly those defining the angle based on the posterior auditory canal wall and facial nerve position, are highly valuable for assessing round window access.
• These parameters are essential for future CT evaluation algorithms, robot-assisted surgery planning, and electrode choice in cochlear implantation.