Changes in Revision Cochlear Implantation and Device Failure Profiles.

OBJECTIVES: With rapid innovation in and expanding indications for cochlear implantation (CI), changes in the features of revision CI (RCI) appear to be emerging. This study aims to investigate the changes in RCI profile and discuss their clinical significance.

METHODS: A retrospective chart review was performed for all CIs performed at a tertiary medical institution between October 2001 and January 2023. The rate and reasons for RCI were evaluated and examined in terms of the manufacturer and device model. The Kaplan-Meier curve was used to examine the cumulative and device survival curves. In addition, the cumulative and device survivals were further analyzed based on age group, time period of primary CI, and manufacturer. Cox proportional hazards model was used to evaluate the association between RCI and manufacturers.

RESULTS: Among 1,430 CIs, 73 RCIs were conducted (5.1%). Device failure was the most common cause of RCI (40 of 73 RCIs [54.8%]), with an overall device failure rate of 2.8%, followed by flap-associated problems and migration (9 of 73 RCIs each [12.3%]). Flap retention problem appeared as a new cause in three cases (two CI 632 and one SYNCHRONY 2), and six electrode tip fold-over occurred (four CI 600 series and two CI 500 series). The 10-year overall cumulative and device survival rates were 93.4% and 95.8%, respectively. After excluding the models with recall issues, cumulative (P=0.010) and device survival curves (P=0.001) revealed significant differences by manufacturer.

CONCLUSION: Although the overall survival of CI appears to be stable, device failure is still the most common cause of RCIs. In addition, the pattern of revision has changed, such as flap retention issue and electrode tip fold-over, particularly for the recently released implant models. Due to the clinical significance of device failure and re-operation, clinicians should be aware of and respond to these changes.