Advanced Bionics has sent a letter to some recipients of the HiRes Ultra / HiRes Ultra 3D noting that some of these devices may have an issue with the electrode array that could adversely affect the performance of the device.  The text of the letter is available here.

Implants that may be affected have been recalled, and the current version available today has resolved the issue. The company says that about 0.5% of recipients of the affected devices have had revision surgery.

To assess the significance of the issue, refer to our analysis of the FDA Manufacturer and User facility Device Experience database. A constant failure rate for a given manufacturer should show a curve that rises with the number of implants in the field. Over the past several years, all three major CI manufacturers show relatively flat numbers of incidents.  As cochlear implants have enjoyed healthy growth in this time frame, the implication is that reliability has been improving steadily.

The Advanced Bionics chart shows a spike in the middle of 2019, which may be related to the recall.  After the middle of 2019, the incident rate seems to have returned to preceding trend. Prior recalls (from any manufacturer) are visible on the charts.

There does seem to be a recent increase in reported events for Cochlear towards the end of 2019 beyond what a trendline would indicate.  Hopefully this is just an anomaly, and not related to any reliability issue. The MED-EL curve appears to be decreasing, which would indicate improved reliability, particularly in a growing market.