Tip fold-over and audiological outcome

Abstract

Introduction: The Slim Modiolar Electrode (CI532) is the latest electrode in the Cochlear portfolio. It is designed to allow a perimodiolar position with an atraumatic insertion and thus combines the advantages of the Contour Advance and the Slim Straight Electrode. Due to its fine structure, the tip can fold over during the insertion process (tip fold-over). We would like to introduce three patients with tip fold-over from the point of view of their audiological outcome. Method(s): Retrospective case analysis. Result(s): Between 2014 and 2017 tip over-fold occurred three times. All three patients were implanted with CI532 at Augsburg Hospital by experienced cochlear implant surgeons. The extent of the tip fold-over varies between one, three and seven knocked-over electrodes. CT scan of the temporal bone was performed after the operation to check the correct positioning of the electrode inside the cochlea. The first three adjustments were made in our clinic, where the affected electrodes were disabled. The first hearing tests show a similar variance as is observed in our collective of CI532-implanted patients without tip fold-over. The hearing tests after 6 months are still pending at the current time. There was no dizziness or costimulation of the facial nerve in any of the patients. Conclusion(s): So far, there is no indication of an a priori poorer outcome, but the medium-term results are still pending. As it is known tip fold-over can occur during an CI532 implantation, an intraoperative position control should be carried out by means of X-ray (fluoroscopy). If the findings are discovered after surgery, the initial data shows that a revision surgery may not be necessary.