Foreign Body Reaction to Cochlear Implant

Two cases of foreign body reaction to a cochlear implant are described. A Nucleus-22 cochlear implant encased in silicone rubber was implanted in both. The first is a 66-year-old patient with idiopathic hearing loss. A year following the procedure, a fistulous tract developed over the implant with a typical histological foreign body reaction. The implant was removed and another Nucleus-22 device implanted on the contralateral side. No reaction to the new implant was noticed during a follow-up period of 7 years. The second case is a 6-year-old boy who developed a stubborn suppurative wound infection immediately following implantation. Upon removal of the implant, 2 months after implantation, granulation tissue was found to be encapsulating all parts of the device. Immediately following explantation, the scar and infection rapidly resolved. The tissue was histologically proven to be due to a foreign body reaction.