Magnet displacement following cochlear implantation.

OBJECTIVE

To describe a rare complication of cochlear implantation, such as magnet displacement.

STUDY DESIGN

Retrospective case review.

SETTING

The study was conducted at the Sheba Medical Center, Tel-Aviv, Israel.

PATIENTS

One child presented with an external coil attached to the skin anteriorly to the receiver/stimulator site (20 months after implantation) and another child was seen with a displaced magnet under the skin a few days after a head trauma (28 months after implantation). Both children were implanted with the Nucleus 24 device at the age of 2 years.

INTERVENTION

Plain skull radiographs showed the dislocated magnet in both cases. Surgery for each child was limited to revision of the receiver/stimulator site and reinsertion of the magnet to its pocket.

RESULTS

Intraoperative Neural Response Telemetry well displayed the responses of evoked potentials of the auditory nerve within the cochlea in both children. Postoperative auditory responses were as good as those measured before the complication.

CONCLUSION

The displaced magnet can be successfully managed by a simple revision procedure. The possibility of magnet migration should be considered in cases of device malfunction. Two cases of magnet migration from its pocket after cochlear implantation are presented. The diagnostic and surgical method used for resolving this condition are described.