Migration of a cochlear implant ground electrode through the calvarium of a pediatric patient.

Cochlear implantation has been performed safely several hundred thousand times, although a variety of complications have been reported including surgical site infection, device failure, migration of the receiver/stimulator or electrode array. Here we report the asymptomatic migration of the ground electrode through the squamous temporal bone, which was discovered at the time of device explantation. The incidence of this phenomenon is not known since it may remain asymptomatic and delayed postoperative imaging is not routinely performed. This finding should motivate implant surgeons to consider placement of the ground electrode into a subperiosteal pocket in a region with greater skull thickness.