목적: This study aimed to analyze the rate and primary causes of revision cochlear implant (CI) surgery (reimplantation) in a post-2012 cohort, comparing domestic (initial CI at the same hospital) and referral (initial CI elsewhere) cases, and evaluating the impact of revision on CI performance. The researchers hypothesized that with advancements in CI technology post-2012, the causes and rates of revision surgeries might have shifted, with functional optimization becoming a more prominent factor. 방법:This retrospective study analyzed data from all CI surgeries performed by a single surgeon at a tertiary referral center between May 2012 and December 2024. The study included patients requiring revision surgery, categorized as domestic or referral. Data collected included demographics, initial CI surgery details, revision details, and reasons for revision (device failure, infection/flap problems, electrode migration, and functional performance concerns). Functional performance concerns were further classified as obligatory (minimal benefit despite functioning device), optional (desire for improved performance despite existing benefit), and device instability. Device survival analysis was performed on domestic CI ears implanted between 2012 and 2022 with at least two years of follow-up, using the Kaplan- Meier method. Competing risks analysis using the Fine-Gray method was used to examine the cumulative incidence of revision surgery due to different causes. Pre- and post-revision CI performance was assessed using speech discrimination scores and CAP scores. 결과:A total of 44 CI revision surgeries were performed (23 domestic, 21 referral). Among 1390 ears with initial CI at the study hospital, the domestic revision rate was 1.65%. The most common reason for revision was functional performance concerns (20 cases), followed by infection/flap problems (16 cases), device failure (6 cases), and electrode migration (2 cases). The device survival probability at 7.1 years post-implantation was 97.0%. Infection/flap-related revisions typically occurred early post-operatively, while functional performance-driven revisions increased gradually over time. Significant improvements in speech discrimination and overall auditory functionality were observed after revision surgery. Obligatory functional revisions in patients with cochlear nerve deficiency (CND) or incomplete partition (IP) type III showed improvement after switching to specific electrode types. Optional functional revisions, often in patients with genetic variants, also showed enhanced speech discrimination after electrode optimization. 결론:This study demonstrated a high CI device survival rate and revealed distinct differences between domestic and referral revision cases. While device failure rates have decreased post-2012, infection prevention and functional optimization remain critical. Revision surgeries play a crucial role in optimizing patient outcomes, offering meaningful improvements in auditory functionality. The increasing focus on functional optimization highlights the evolving understanding of CI success, encompassing not just device function but also the patient's desired level of auditory performance. Specific electrode selection for anatomical variations like CND and IP type III can further optimize outcomes.