Strong Audibility Following Revision Cochlear Implantation: An International Vendor Recall

Introduction: Advanced Bionics, a cochlear implant (CI) manufacturer, initiated a field action notice in 2020 for the removal of the HiRes Ultra Mid-Scala (V1) electrode due to a manufacturing defect. Electrode failure was characterized by a decline in electrical impedances below 3.5 kΩ and decreased speech understanding of over 15%. This study identifies electrode failure in a cohort of V1 recipients at a single implant centre and evaluates speech performance with a new device post-reimplantation.

Methods: A retrospective cohort study was conducted on 68 V1 devices (61 patients) involved in the manufacturer recall. Device failure rate was appraised. Sentence-level speech perception (AzBio) measures and electrode impedance levels were obtained on reimplanted adult CI recipients. Performance was evaluated and compared to baseline (1-year post activation) with the V1 electrode and to the general cohort of CI recipients at the institution.

Results: To date, 63.2% (43/68) of V1 devices at the centre have signs of electrode failure. Of these, 24 have been reimplanted, and 4 devices are pending revision. An additional 16 devices are being monitored for failure. AzBio speech perception in the revision population is 72.4% [+/- 19%], equivalent to the general cohort of implant recipients at the institution. This represents a significant improvement over V1 performance at point of failure (34.8% [+/- 21%]) and over baseline with the V1 electrode, 1-year post-activation (61.5% [+/- 28%]). Electrical impedances in all reimplanted patients are normative.

Conclusions: This study demonstrates a high rate of V1 failure. Individuals having undergone reimplantation have good auditory outcomes, comparable to a general CI cohort at the same time post-activation.