■ OBJECTIVE: To review the postoperative radiographical investigations ofpatients implanted with a cochlear implant.

■ MATERIAL AND METHOD: Retrospective case series of 39  patients implanted with acochlear implant for deafness. A retrospective analysis of the postoperativect-scans. Cochlear implantation with Cochlear Nucleus 24 Contour and CochlearNucleus Freedom implant

■ RESULTS: This analysis of the postoperative ct-scans showed that in alarge number of the implantations the external ball electrode of the cochlearimplant was migrated from the insertion place towards the magnet of thereceiver stimulator unit of the implant. It seems that this migration of theexternal ball electrode does not influence the function of the cochlear implantand the result of the hearing rehabilitation on the short term.

■ CONCLUSION: Due to the magnetic field of the receiver stimulator unit ofthe cochlear implant and the magnet of the external transmitting coil of thespeech processor it seems to be possible that the extracochlear ball electrodecan migrate in the space between the temporal bone and the temporal muscleduring the postoperative healing phase. The importance of our observation is still not clear.