Systematic Review of Postcochlear Implant Electrode Migration: What Is Known?

Electrode migration after cochlear implantation (CI) is a rare complication that accounts for 1to 15% of all revision surgery. This study is a systematic review of the literature for investigating the knowledge and approaches to the incidence of electrode migration after CI.

A systematic electronic search of the literature was carried out using PubMed, Cochrane, Virtual Health Library, Scopus and Web of Science (ISI). All original articles that reported electrode migration after CI surgery were included. The Newcastle-Ottawa Scale and CARE checklist were utilized for the assessment of the risk of bias. Descriptive data analysis was performed using SPSS software.

A total of 26 studies including 4,316 patients were included. Out of them, 289 patients had electrode migration following CI. To diagnose electrode migration, traditional computed tomography scan was used in 13 studies, while cone-beam computed tomography was applied in three studies. In addition, electrode migration was detected during intraoperative exploration in eight studies. The most common presenting symptom was change in sound/poor performance (n = 43) followed by pain sensation (n = 15) and facial nerve stimulation (n = 10). Cholesteatoma was the most common associated pathology (n = 10) followed by infection (n = 9) and ossification of the basal turn of the cochlea (n = 8).

Electrode migration is a major complication of CI and could be more common than previously thought. As it may occur with or without clinical complaints, long-term follow-up through routine radiological scanning is recommended. Further studies are warranted to identify the underlying mechanism of electrode extrusion and the appropriate fixation method.