Cochlear Implant Fixation Techniques: A Systematic Review of the Literature

Objective: Given the lack of consensus on fixation techniques of the cochlear implant, this review aims to create an up-to-date overview of intra- and postoperative complications, focusing on migration of the internal receiver/stimulator (R/S) device and the electrode array. Data Sources: On June 29, 2020 we conducted a search in PubMed, Embase, Cochrane, Web of Science, and CINAHL. Keywords were "Cochlear implant," "complication," "migration," and synonyms. Study Selection: Studies were considered if: 1) the adult study population consisted of >= 10 patients, 2) the R/S device was fixated using the bony well or tight subperiostal pocket technique without bone-anchoring sutures or screws on the implant, and 3) migration of the R/S device or displacement of the electrode array were described as outcomes. Data Extraction: Study characteristics, interventions, follow-up, and outcomes were extracted. For critical appraisal, an adapted version of the Newcastle-Ottawa quality assessment scale for cohort studies was used. Data Synthesis: Seven studies were included (n = 430 patients). Migration of the R/S device was reported by three studies. Two studies applying the tight pocket technique reported migration rates ranging from 9.0 to 69.2%. One study using the bony bed technique reported migration of 100%, with an average of 2.5 mm. All studies lacked the required standard for comparability, assessment of outcome, and follow-up. Conclusions and Relevance: There is currently no evidence of a difference between the bony bed- and tight pocket fixation technique, regarding migration of the R/S device or the electrode array, in adult patients.