Intracochlear Trauma and Local Ossification Patterns Differ Between Straight and Precurved Cochlear Implant...

Area of Science:

• Otolaryngology
• Neurosurgery
• Biomedical Engineering

Background:

• Minimizing intracochlear trauma during cochlear implant (CI) insertion is crucial for preserving hearing and limiting tissue reactions.
• Previous studies suggested localized tissue formation post-CI, but quantitative evidence was lacking.

Purpose of the Study:

• To quantitatively assess the extent and localization of intracochlear ossification and fibrosis following CI insertion trauma.
• To investigate the correlation between electrode type and the pattern of tissue response.

Main Methods:

• Histological analysis of 21 human temporal bones with CI.
• 3D reconstruction and virtual resectioning of cochlear tissues.
• Quantification of ossification and fibrosis volume at trauma sites and adjacent regions.

Main Results:

• Osseous spiral lamina (OSL) fractures occurred exclusively with precurved electrodes.
• Localized intracochlear ossification was significantly higher at OSL fracture sites compared to other regions.
• Spiral ligament (SL) perforations, common with straight electrodes, did not show localized ossification or fibrosis.

Conclusions:

• OSL fractures from precurved electrodes may initiate localized intracochlear ossification.
• SL perforations from straight electrodes are not associated with localized ossification.
• Electrode type influences the pattern and localization of tissue response to CI insertion trauma.