Figure 1
a, b. Stenver’s views of correctly placed bilateral cochlear implants with electrodes visible within the cochlea.
Figure 2
Axial CT image of a misplaced left cochlear implant electrode entering the carotid canal.
Figure 3
Schematic representation of intracochlear electrode placements. The orange line represents the electrode array and the orange squares represent active electrodes. The blue line marks the level of the cochleostomy (entrance to the cochlea).
a. Full insertion into the cochlea. All active electrodes are medial to the cochleostomy. Optimal placement is when the most proximal active electrode is as close as possible to the cochleostomy but still within the cochlea.
b. Electrode tip fold-over. The tip of the electrode has folded back on itself due to resistance to insertion while advancing the electrode.
c. Electrode kinking. A portion of the electrode has twisted on itself due to resistance to insertion while advancing the electrode.
d. Electrode under-insertion or extrusion. In under-insertion the electrode has not been advanced sufficiently so that all active electrodes are medial to the cochleostomy. Several active electrodes are therefore outside of the cochlea. In the case of extrusion, the electrode has slipped back via the cochleostomy, after insertion, leaving one or more electrodes lateral to the cochleostomy.
Figure 4
Modified Stenver’s view of a right cochlear implant with electrode tip roll over.
Figure 5
Modified Stenver’s view of right cochlear implant with electrode tip roll over and kinking leading to incomplete insertion.
Figure 6
AP skull radiograph of correctly placed bilateral cochlear implants.
Figure 7
Modified Stenver’s view of a correctly placed left cochlear implant.
Figure 8
Modified Stenver’s view of an underinserted left cochlear implant.
Figure 9
Modified Stenver’s view of an extruded right cochlear implant.