Frequency of electrode migration after cochlear implantation in the
early postoperative period. What are associated risk factors?
Abstract
Objectives: To investigate the prevalence and risks factors associated
with electrode migration in cochlear implant (CI) recipients. Design:
Retrospective cohort study of all CIs performed between 1 January 2018-1
August 2021 in a single tertiary adult and paediatric cochlear implant
centre in the UK. Main outcome measures: The primary aim is to determine
the prevalence of electrode migration, based on comparing intraoperative
surgeon report and results of a routine plain X-ray performed 2 weeks
after surgery. Electrode migration is defined as the detection of
movement of 2 or more electrodes out of the cochlea from time of
surgery. Multivariate analysis was performed to investigate risk factors
including preoperative factors and intraoperative factors that might
predispose to migration. Results: 465 patients, having 516 distinct
surgery sessions, with 628 implants were analyzed. Electrode migration
occurred in 11.5% of all implants. Pre-existing cochlear abnormality
was an independent associated risk factor for electrode migration
(OR:3.40<1.20-9.62> p=0.021). Demographics,
surgical technique, usage of a precurved electrode, CSF leak, surgeon
seniority and intraoperative telemetry did not influence risk of
migration. There were 5 implants which migrated later than 2 weeks,
median: 263days, for which head injury was a common precipitating
factor. There was some difference between different lateral wall
electrodes Conclusion: Electrode migration in the early postoperative
period is a common occurrence and is more likely in implant recipients
with obstructed or malformed cochleae. Keywords : Cochlear implants,
Electrode migration, Risk factors, Cochlear abnormalities, Postoperative
X-ray