Incidence and Risk Factors of Cochlear Implant Complications: A Systematic Review and Meta-Analysis

Objective: This review aimed to evaluate the existing literature to determine the incidence and associated risk factors of cochlear implant complications. Data Sources: A comprehensive literature search was conducted across PubMed, Web of Science, Embase, and Scopus up to 12 April 2025. Methods: The review protocol was registered on PROSPERO (ID: CRD420251012225) on 15 March 2025, and the systematic review was performed according to PRISMA guidelines. Results: We included a total of 100 records based on 81 studies with 42,167 patients. The overall incidence was 13.7%. Major complications occurred in 5.2%, with device failure being the most common at 2.8%. Minor complications affected 7.8%, with superficial wound infections being most frequent at 2.3%. Vestibular complications (vertigo/dizziness) were prevalent at 12.4%. Adults had significantly higher overall and major complication rates compared to pediatric patients. The mastoidectomy with posterior tympanotomy approach (MPTA) was associated with lower rates (5.4%) than the suprameatal approach (SMA) (7.8%). A significant temporal trend showed decreased complication rates from 8.9% in the early era (1991-2010) to 4.1% in the recent era (2011-2025). Significant risk factors were identified including older age at implantation, inner ear malformations, chronic otitis media, previous otologic surgery, and longer surgery duration. A substantial heterogeneity was present across the included studies (I² up to 93.6%), and the evidence base was predominantly retrospective in nature, which limits the certainty of these estimates. Conclusions: Cochlear implantation appears to be a generally safe procedure. However, these findings should be interpreted with caution. The high heterogeneity, predominantly retrospective study designs, inconsistent complication definitions, and detected publication bias collectively limit the certainty of the pooled estimates. Standardized complication reporting, prospective multicenter designs, and consensus-based outcome definitions are essential to strengthen the evidence base and guide safer clinical practice.