COCHLEAR IMPLANTATION IN YOUNG-CHILDREN - HISTOLOGICAL STUDIES ON HEAD GROWTH, LEADWIRE DESIGN, AND ELECTRODE FIXATION IN THE MONKEY MODEL

For safe cochlear implantation in children under 2 years of age, the i mplant assembly must not adversely affect adjacent tissues or compromi se head growth. Furthermore, growth changes and tissue responses shoul d not impair the function of the device. Dummy receiver-stimulators, i nterconnect plugs, and leadwire-lengthening systems were implanted for periods of 36 months in the young monkey to effectively model the imp lantation of the young child. The results show that implanting a recei ver-stimulator package has no adverse effects on skull growth or the u nderlying central nervous system. The system for fixing the electrode at the fossa incudis proved effective. There was marked osteoneogenesi s in the mastoid cavity, resulting in the fixation of the lead-wire ou tside the cochlea. This study provides evidence for the safety of coch lear implantation in young subjects.