Cochlear Implantation: Predicting Round Window Niche Visibility Using One Measurement in High-Resolution Temporal...

Area of Science:

• Otolaryngology
• Neurosurgery
• Radiology

Background:

• Cochlear implantation requires clear visualization of the round window niche (RWN).
• Predicting RWN visibility preoperatively can optimize surgical outcomes.
• Temporal bone computed tomography (CT) is a key imaging modality.

Purpose of the Study:

• To assess the accuracy of a single CT measurement in predicting RWN visibility.
• To determine if the angle of the basal turn of the cochlea (ABTC) can predict RWN visibility during cochlear implantation.

Main Methods:

• A prospective study of 165 ears undergoing cochlear implantation (CI).
• Measurement of the ABTC, defined as the angle between the cochlear basal turn and the cranium's mid-sagittal plane, from axial CT images.
• Correlation of ABTC measurements with intraoperative RWN visibility (full, partial, invisible).

Main Results:

• The average ABTC was 57.48° ± 4.05°.
• RWN visibility was: 85% full, 11% partial, 4% invisible.
• An ABTC threshold of 58.5° significantly predicted RWN visibility (P <.001), with larger angles associated with poorer visibility.

Conclusions:

• Preoperative CT measurement of ABTC can predict RWN visibility.
• An ABTC > 58.5° indicates a higher likelihood of poorly visible RWN.
• This measurement aids in surgical planning for cochlear implantation.