Long-term reliability of pediatric cochlear implants

Abstract

Objective: This study defines a method of interpreting cumulative survival rate for pediatric cochlear implants (CIs) that is applicable to the time span when hearing is most critical for speech and language development. In addition, it applies this method to published data reporting pediatric device failures.

Patients: Pediatric CI recipients for whom cumulative survival rates have been published were the patient population, consisting of 2009 recipients.

Intervention: Pediatric cochlear implantation.

Main outcome measure: The main outcome measure was cumulative survival rate (CSR), defined as the percentage of CIs that are functional, calculated as a function of time after implantation. This measure was reported for time periods from 4 to 19 years for devices made by 3 CI manufacturers.

Results: Cumulative survival rates at 18 years were predicted by extrapolating regression functions to published data. Predicted 18-year CSRs express the likelihood that the device will function throughout child development after early implantation. Devices with titanium casing exhibited 18-year CSRs from 0.900 to 0.988 for a monolateral implants and from 0.810 to 0.976 for both bilateral implants. Devices with ceramic casings had 18-year CSRs of 0.740 to 0.944 for monolateral implants and 0.548 to 0.871 for bilateral implants.

Conclusion: Use of 18-year CSRs allows comparison of survival rates obtained from data over different time intervals and is based on the time course of normal development. These values provide a conservative and meaningful estimate of device reliability for pediatric recipients. The higher failure rates of ceramic devices for children are likely due to the greater incidence of head trauma from impact and/or leakage from cracked casings seen in this population.