Learning from reimplantation
Reviewed by Kerri Millward & Morag Lockley

The Irish implant centre in Dublin undertook a retrospective study of their reimplantation cases to look at what lessons could be learnt. Device failures fall into two classes: hard and soft failures. Hard failures are implant malfunction or altered performance. A soft failure is when the device may still be working to specification but the patient has poorer performance than expected, which subsequently improves after reimplantation. Since 1995, 60 devices required revision surgery. Most of the cases were due to device failure (63.3%) and the rest (36.7%) were due to other medical reasons. The paediatric population had a higher percentage of failures mainly because of trauma. The majority of hard failures were because of hermetic sealing failures whereas the majority of the soft failures were because of an internal package or wound complications. Hard failures are often easier to diagnose because implant testing identifies a problem. There can also be implant recalls so that the clinician is aware of potential problems with an implant such as with the CI512 implant. However, soft failures can be difficult to diagnose as implant testing can show the device to be functioning, but evidence gathered from multiple appointments can show that performance isn’t as expected. For example, in the case mentioned where the immune system reacted to the implant, information would have been gathered over a series of appointments. Because devices can fail due to both medical and device issues a multidisciplinary team approach is often needed for a successful outcome to be achieved.

Revision cochlear implantation: The Irish experience.
Wijaya C, Simões-Franklin C, Glynn F, et al.
COCHLEAR IMPLANTS INTERNATIONAL
2019;20(6):281-7.