To analyze the cause and effect of magnet dislocation in cochlear implant (CI) recipients requiring magnet revision surgery for treatment.
Tertiary referral center.
Case reports from 1,706 CI recipients consecutively implanted from January 2000 to December 2011 were reviewed. The number of cases requiring magnet revision surgery was assessed.
Revision surgery involving magnet removal or replacement was indicated in 1.23% (21/1,706), of all CI recipients. Magnet dislocation occurring during magnetic resonance tomography (MRI), at 1.5 Tesla (T), with the magnet in place and with the application of compression bandaging around the head, was the main cause for revision surgery in 47.62% (10/21) of the affected cases. All 10 cases were implanted with Cochlear Nucleus cochlear implants. These events occurred, despite adherence to current recommendations of the manufacturer.
The present study underlines that MRI examination is the main cause of magnet dislocation. The use of compressive bandaging when using 1.5-T MRI does not eliminate the risk of magnet dislocation. Additional cautionary measures are for required for conditional MRI. We recommend X-ray examination after MRI to determine magnet dislocation and avoid major complications in all cases reporting pain during or after MRI. Additional research regarding silicon magnet pocket design for added retention is needed. Effective communication of guidelines for precautionary measures during MRI examination in CI patients is mandatory for all clinicians involved. MRI in CI recipients should be indicated with caution.
Department of Otorhinolaryngology–Head and Neck Surgery, University Medical Center Freiburg, Freiburg, Germany
Address correspondence and reprint requests to Frederike Hassepass, M.D., University Medical Center Freiburg, Department of Otorhinolaryngology–Head and Neck Surgery, Killianstr. 5, 79106 Freiburg, Germany; E-mail: email@example.com
The authors disclose no conflicts of interest.