Extracochlear cochlea implants – a dead-end street in the evolution of the modern CI
23 April 2019 (online)
In the 1980 s, extracochlear implants were developed and assessed clinically, apart from intracochlear implants that are used today as standard. An electrode array, the so called “hedgehog”, was fixed on the cochlea from outside on the medial wall of the tympanic cavity. Since 1985, an implant with 16 electrodes, two of them free and 14 fixed on the electrode array, was assessed clinically.
A male patient who underwent implantation of an extracochlear implant on the right side in 1986 at the age of 18 presented with recurrent infection of the device. According to the patient, it worked only for half a year. In the right retroauricular area, he had a percutaneous plug connection that was used for coupling the external processor. In the CT-scan the tympanal position of the electrodes was confirmed. The temporal bone was partially destroyed by inflammation.
Because of recurrent infections of the implant and temporal bone, the decision was made to remove the device surgically. The implant including the plug connection and the electrode array could be taken out completely. 10 weeks postoperatively, there were no signs of infection and wound healing was adequate.
Extracochlear cochlear implants play no longer a roll in hearing restoration. Our case report shows that even more than 30 years after implantation, patients have to struggle with the negative effects of these implantations.