Preservation of cochlear structures and hearing when using the Nucleus Slim Straight (CI422) electrode in children.

Objective: In cochlear implantation, there are two crucial factors promoting hearing preservation: an atraumatic surgical approach and selection of an electrode that does not damage cochlear structures. This study aimed to evaluate hearing preservation in children implanted with the Nucleus Slim Straight (CI422) electrode.
Methods: Nineteen children aged 6-18 years, with partial deafness, were implanted using the 6-step Skarzynski procedure. Electrode insertion depth was 20-25 mm. Hearing status was assessed with pure tone audiometry before surgery, and at 1, 5, 9, 12 and 24 months after surgery. Electrode placement was confirmed with computed tomography.
Results: Mean hearing preservation in the study group at activation of the cochlear implant was 73 per cent (standard deviation = 37 per cent). After 24 months, it was 67 per cent (standard deviation = 45 per cent). On a categorical scale, hearing preservation was possible in 100 per cent of cases.
Conclusion: Hearing preservation in children implanted with the Nucleus CI422 slim, straight electrode is possible even with 25 mm insertion depth, although the recommended insertion depth is 20 mm. A round window approach using a soft, straight electrode is most conducive to hearing preservation.