OBJECTIVE: To identify the prevalence of individual electrode failures as a result of open and short circuits in the Nucleus N24 and Freedom series and the Advanced Bionics CII and HR90k (Helix and 1J) devices. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Age at implantation, date of surgery, device type, and other relevant demographic data in addition to telemetry and impedance data were collected on 636 implants. INTERVENTION(S): Individual electrode circuit failures were identified using impedance testing performed intraoperatively and during subsequent programming sessions. MAIN OUTCOME MEASURE(S): Individual electrode failures were categorized as either "short" or "open" circuits as determined by manufacturer software algorithms. RESULTS: Combining all devices, the risk of 1 or more failures as determined by impedance telemetry is 9.0%. Three or more individual electrode circuit failures within an array may indicate impending deterioration of device performance and future need of reimplantation. CONCLUSION: Open and short circuits are routinely encountered. They can be managed by deactivating the affected electrode(s), and conventional wisdom states that this has little impact on performance. However, it is true that multiple failures are often associated with decreased performance and often lead to revision surgery. Certainly, every patient would prefer to have a fully functional device. Continued reporting of individual electrode circuit failures is critical to product development and improving overall device reliability.
OBJECTIVE: To identify the prevalence of individual electrode failures as a result of open and short circuits in the Nucleus N24 and Freedom series and the Advanced Bionics CII and HR90k (Helix and 1J) devices. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Age at implantation, date of surgery, device type, and other relevant demographic data in addition to telemetry and impedance data were collected on 636 implants. INTERVENTION(S): Individual electrode circuit failures were identified using impedance testing performed intraoperatively and during subsequent programming sessions. MAIN OUTCOME MEASURE(S): Individual electrode failures were categorized as either "short" or "open" circuits as determined by manufacturer software algorithms. RESULTS: Combining all devices, the risk of 1 or more failures as determined by impedance telemetry is 9.0%. Three or more individual electrode circuit failures within an array may indicate impending deterioration of device performance and future need of reimplantation. CONCLUSION: Open and short circuits are routinely encountered. They can be managed by deactivating the affected electrode(s), and conventional wisdom states that this has little impact on performance. However, it is true that multiple failures are often associated with decreased performance and often lead to revision surgery. Certainly, every patient would prefer to have a fully functional device. Continued reporting of individual electrode circuit failures is critical to product development and improving overall device reliability.