Electrode–Modiolar Distance as a Determinant of Cochlear Implant Performance: A Systematic Review and Meta‐Analysis
Nidhin Das K, Vidhu Sharma, Siddharth Manoj, Amit GoyalABSTRACT
Objective
To quantify the relationship between electrode–modiolar distance (EMD) and cochlear implant (CI) performance across speech/perceptual, electrophysiological and programming outcomes and to characterize the dose–response effect of EMD.
Methods
A systematic search of PubMed/MEDLINE, Embase, Scopus, Web of Science and Cochrane CENTRAL was conducted in accordance with PRISMA guidelines. Human studies reporting CT‐ or CBCT‐derived EMD and CI outcomes were included. Effect sizes were transformed to odds ratios (ORs) and pooled using random‐effects models. Subgroup, sensitivity and dose–response analyses were performed. Heterogeneity was assessed using I 2 , and publication bias was evaluated using funnel plots and Egger's test.
Results
Twenty‐one studies comprising approximately 1181 implanted ears were included. Reduced EMD was associated with significantly higher odds of favourable CI outcomes (pooled OR = 2.16, 95% CI: 1.89–2.45; p < 0.001; I 2 = 0%). Consistent effects were observed for speech/perceptual outcomes (OR = 2.23), electrophysiological measures (OR = 2.80 after sensitivity adjustment) and programming parameters (OR = 1.72). Dose–response modelling demonstrated a monotonic gradient, with each 1 mm increase in EMD associated with a 20%–30% reduction in the odds of favourable outcomes (OR per mm ≈0.72; p < 0.001). No significant publication bias was detected (Egger's p = 0.056).
Conclusion
Electrode–modiolar proximity is a strong and consistent determinant of CI performance with a clear dose–response relationship, supporting its role as a clinically actionable imaging biomarker for optimizing electrode selection, surgical strategy and individualized programming.
Trial Registration
PROSPERO: CRD420261380236