Clinical Validation of Manual Measurement of Cochlea Length With Post-Operative Electrode Insertion Depth: A Pilot...

Area of Science:

• Otolaryngology
• Neurosurgery
• Medical Imaging

Background:

• Accurate selection of cochlear implant (CI) electrode length is crucial for successful auditory restoration.
• Pre-operative assessment of cochlear anatomy aids in determining the appropriate CI electrode size.
• Manual measurement of cochlear dimensions from imaging provides a basis for surgical planning.

Purpose of the Study:

• To clinically validate manual measurement of cochlear length from pre-operative images.
• To compare pre-operative cochlear length measurements with post-operative cochlear implant (CI) electrode length.
• To assess the feasibility of using manual cochlear length measurements for selecting CI electrode length.

Main Methods:

• Temporal bone computed tomography (CT) scans from 23 ears were analyzed.
• Three-dimensional (3D) segmentation of the inner ear was performed to manually measure cochlear length.
• Post-operative CT scans were used to reconstruct the CI electrode's position and measure its intra-cochlear length for validation.

Main Results:

• Cochlear length was measured for specific angular depths based on inner ear anatomy (e.g., 650° for normal anatomy, 540° for EVAS/otosclerosis, 360° for IP type I).
• CI electrode length selection was based on the pre-operative cochlear length measurements.
• Full insertion of the selected electrode was achieved in 19 out of 23 ears; partial insertion occurred in 4 ears across different anatomical types.

Conclusions:

• Manual measurement of cochlear length from 3D images is a practical approach for selecting CI electrode length.
• This method allows for tailoring electrode selection to achieve preferred angular insertion depths based on cochlear anatomy.
• The findings support the clinical utility of manual cochlear length measurement in optimizing CI electrode selection.