Tip Fold-over in Cochlear Implantation: Case Series. Issue 2 (February 2017)

• Record Type: Journal Article
• Authors: Zuniga, M. Geraldine; Rivas, Alejandro; Hedley-Williams, Andrea; Gifford, Rene H.; Dwyer, Robert; Dawant, Benoit M.; Sunderhaus, Linsey W.; Hovis, Kristen L.; Wanna, George B.; Noble, Jack H.; Labadie, Robert F.
• Is Part Of: Otology & neurotology. Volume 38:Issue 2(2017)
• Publication Date: 2017-02
• Subjects: Cochlear implant failure -- Cochlear implant revision -- Electrode tip fold-over; Otology -- Periodicals; Ear -- Diseases -- Periodicals; Skull base -- Surgery -- Periodicals; 617.8005
• DOI: 10.1097/MAO.0000000000001283
• Languages: English
• ISSNs: 1531-7129

Abstract

Abstract : Objective: To describe the incidence, clinical presentation, and performance of cochlear implant (CI) recipients with tip fold-over. Study Design: Retrospective case series. Setting: Tertiary referral center. Patients: CI recipients who underwent postoperative computed tomography (CT) scanning. Intervention(s): Tip fold-over was identified tomographically using previously validated software that identifies the electrode array. Electrophysiologic testing including spread of excitation or electric field imaging (EFI) was measured on those with fold-over. Main Outcome Measure(s): Location of the fold-over; audiological performance pre and postselective deactivation of fold-over electrodes. Results: Three hundred three ears of 235 CI recipients had postoperative CTs available for review. Six (1.98%) had tip fold-over with 5/6 right-sided ears. Tip fold-over occurred predominantly at 270 degrees and was associated with precurved electrodes (5/6). Patients did not report audiological complaints during initial activation. In one patient, the electrode array remained within the scala tympani with preserved residual hearing despite the fold-over. Spread of excitation supported tip fold-over, but the predictive value was not clear. EFI predicted location of the fold-over with clear predictive value in one patient. At an average follow-up of 11 months, three subjects underwent deactivation of the overlapping electrodes with two of them showing marked audiological improvement. Conclusion: In a large academic center with experienced surgeons, tip fold-over occurred at a rate of 1.98% but was not immediately identifiable clinically. CT imaging definitively showed tip fold-over. Deactivating involved electrodes may improve performance possibly avoiding revision surgery. EFI may be highly predictive of tip fold-over and can be run intraoperatively, potentially obviating the need for intraop fluoroscopy.