Cadaveric Percutaneous CI with AB, Cochlear, and Medel Electrodes

Abstract

Objective: 1) Describe advances made in percutaneous cochlear implantation (PCI) that involves a minimally invasive approach to the cochlea via a single, image-guided drill pass from the lateral cranium through the facial recess. 2) Demonstrate implementation of PCI in cadavers using Advanced Bionics (AB), Cochlear, and Medel electrodes. Method: PCI was performed on 7 cadaveric temporal bones with 2 AB, 2 Cochlear, and 3 Medel electrodes. This included preoperative CT scanning and PCI trajectory planning, placement of bone-implanted fiducial markers, intraoperative CT, CT registration, creation and attachment of customized microstereotactic frame, drilling from cortex to cochlea, and CI insertion. Results: PCI was successfully performed on all 7 specimens using the AB insertion tool for AB electrodes and via manually threading and endaural advancement for Cochlear and Medel electrodes. Postoperative electrode position was assessed by CT scanning and histopathology. CT correctly predicted 6 of the 7 electrodes to be in scala tympani and 1 in scala vestibuli. Histopathology revealed minimal insertion trauma with preservation of the osseous spiral lamina and basilar membrane and complete scala tympani insertion in 6 of 7 specimens. One specimen, due to violation of the basilar membrane at the round window cochleostomy, had complete scala vestibuli insertion. Conclusion: This is the first description of complete PCI using AB, Cochlear, and Medel electrodes. Using various insertion techniques, atraumatic electrode insertion was achieved in the majority of specimens, similar to results clinically reported for traditional CI surgery. Building on this, we anticipate clinical implementation of PCI in the near future.