Asking if a child will 'outgrow' the implant and it will need to be repositioned is a reasonable concern to have, but of course it's one that surgeons address as part of the careful planning they do when determining the implant site. The cochlea and middle ear structures are at adult size when a child is born, that doesn't continue to grow. The mastoid bone does. So, the 'wiring' is at adult length, and the bit of slack that exists for a child is placed in position right up by the skull so that as the mastoid bone increases in size, it slowly draws on the slack in the electrode lead without displacing the array that's much deeper. There are several 'anchors' in place, including one that supports the array and resists any 'pulling' out of position as the body's tissues shift during the healing process and over time. And the 'bed' that the receiver, the part of the implant placed against the skull, is created with room for growth, with comfortable placement of the exterior coil in mind, and well away from the incision itself to avoid any wearing down of the healing skin (that's why there's such a distance between the scar/insertion point and the implant itself).