Determinants of Success in Revision Cochlear Implant Surgeries: A Comprehensive Evaluation of Patient, Surgical, and Radiological Factors

Abstract

Background/Objectives: This study aims to evaluate factors influencing revision cochlear implant surgeries, including patient demographics, surgical techniques, and radiological findings. The main aim was to identify factors influencing surgical success to inform clinical treatment and enhance patient outcomes. Methods: This cross-sectional study included adult patients over the age of 18 who underwent revision cochlear implant surgery due to implant-related complications. Data were collected from systematic chart reviews of electronic medical records, including demographics, surgical techniques, radiological output from standard high-resolution CT and MRI, and intraoperative data. The primary outcome was surgical success, defined by improved auditory function, stable device positioning, and absence of postoperative complications. Statistical analyses, including multivariate logistic regression, were conducted to identify independent predictors of surgical success. Results: A total of 188 patients were included, with a mean age of 45.67 years. Younger age, shorter duration of implant use, modified surgical techniques, and absence of co-morbidities are key factors contributing to surgical success. Modified surgical techniques were associated with better outcomes (39.29% vs. 68.75%, OR: 2.78, 95% CI: 1.25-6.14, p = 0.012). Radiological patterns significantly affected outcomes, with normal findings associated with higher success rates. In contrast, abnormalities such as electrode migration (OR: 2.14, 95% CI: 1.12-4.09, p = 0.021) and ossification (r = -0.51, β = -0.44, adjusted R² = 0.25, p < 0.01) were correlated with poorer results. Smoking status, when comparing smokers to non-smokers, was associated with unfavorable outcomes (20.00% vs. 45.83%, OR: 2.01, 95% CI: 1.01-4.01, p = 0.048), and a history of previous surgeries (21.43% vs. 37.50%, OR: 1.95, 95% CI: 1.03-3.71, p = 0.033) was significantly associated with unfavorable outcomes. Conclusions: Statistically, significantly better outcomes are positively correlated with the duration of the first cochlear implant experience and negatively with prior otologic pathology and nonauditory environmental influences on surgical success. Younger age, modified surgical techniques, and normal radiological findings were related to better outcomes; complications such as electrode migration and ectopic ossification were strong predictive factors for surgical failure. These findings underscore the need for tailored surgical approaches and early intervention to enhance outcomes in revision cochlear implant surgeries.

Keywords: cochlear implant; radiological findings; revision surgery; surgical success; surgical techniques.

Figure 1

Heatmap of radiological findings and their association with surgical outcome metrics (the poorer outcomes observed in cases of corrected electrode migration reflect the irreversible impacts of initial structural or neural damage and the challenges in achieving optimal electrode positioning during revision surgeries, compounded by factors such as fibrosis or altered anatomy).

Figure 2

Comparison of success rates by surgical technique across radiological abnormalities: standard vs. modified techniques. (Higher success rates associated with “Normal findings” reflect the absence of structural complications, allowing revision surgeries to address functional issues with minimal anatomical challenges. In contrast, abnormal findings often necessitate complex interventions to manage structural damage, limiting the extent of improvement achievable.).