We report a case of extrusion of the internal magnet of a CI24M cochlear implant after 1.5 Tesla MRI examination in an adult patient.
MRI at 1.5 Tesla was performed several times in the patient, as he had been diagnosed as having hypertrophic pachymeningitis. In accordance with the manufacturer’s recommendation, the internal magnet was not removed, but a compressive head bandage and a splint were used to hold it in place during the MRI. The patient complained of severe pain during the last MRI and complained of continuous skin irritation over the implant site after the MRI. Six months after the MRI, the internal magnet extruded through the skin. The site, however, healed quickly without infection. After revision surgery with replacement of the magnet, the implant became fully functional again.
A CT performed immediately after the last MRI revealed dislocation of the internal magnet of the cochlear implant.
Thus, in cochlear implant patients who complain of pain during or after MRI examination, a plain skull radiograph should be obtained for early confirmation of magnet dislocation, and appropriate treatment should be initiated as soon as possible in order to avoid serious complications.
