Progression of the Advanced Bionics Ultra V1 issue over time: Evidence from Recording Electrode Voltages and Electric Field Imaging

Abstract

Background and Aims:
Advanced Bionics Ultra V1 devices are vulnerable to partial short circuits, resulting from moisture ingress.
The aim of this study is to assess the extent to which 79 Advanced Bionics devices, supported by the University of Southampton Auditory Implant Service, are affected by the issue and how this has changed over time, with a view to predicting future service requirements.

Method
Devices were assessed by Recording Electrodes Voltages using surface electrodes (REVS test) and the manufacturer’s Electric Field Imaging (EFI) test. Children’s devices were assessed routinely, whilst those implanted in adults were assessed when concerns were raised, or the device reached 3-4 years old.
Electrode Voltages were measured for three montages whilst the implant was stimulated in live mode. Measured voltages were compared across electrodes and electrodes displaying a consistent drop in amplitude compared to adjacent electrodes in different montages were labelled as faulty. The manufacturer’s EFI analysis tool was used to interpret EFI results.

Results
138 REVS tests were performed over a 30 month period for 66 devices: 81 in adults and 57 in children. 17 devices were explanted due to faulty electrodes (range 1 to 15) and one was explanted for medical reasons, all of which were confirmed to have the fault when the explanted device was analysed. A further 35 devices still in situ were identified as having faulty electrode(s) (range 1 to 8), based on the REVS test. In 32 of the 66 devices tested, the issue had progressed sufficiently to register on the manufacturer’s EFI test.

Conclusions
These devices are widely affected by loss of volume, related to partial short circuits. In some cases it is possible to mitigate the effects by adjusting comfort levels, spanning or deactivating electrodes but the extent of the problem is sufficient to justify re-implantation in many cases.

More information

Identifiers

ORCID for Kate Hough: orcid.org/0000-0002-5160-2517

ORCID for Tracey Newman: orcid.org/0000-0002-3727-9258

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