Figure 5: Growth of the middle ear versus mastoid: the mastoid tip develops, whereas the middle ear dimensions remain the same. The distance of the round window to the fossa incudis and facial recess does not change over time, but the mastoid process increases in size. When the electrode is fixed to the mastoid tip, the increasing distance from round window to mastoid tip could cause a possible displacement of the electrode out of the cochlea. Adapted from Dahm et al. [8].