Electrocochleography Observations in a Series of Cochlear Implant Electrode Tip Fold-Overs. Issue 4 (April 2021)

• Record Type: Journal Article
• Authors: Trecca, Eleonora M. C.; Adunka, Oliver F.; Mattingly, Jameson K.; Hiss, Meghan M.; Cassano, Michele; Malhotra, Prashant S.; Riggs, William J.
• Is Part Of: Otology & neurotology. Volume 42:Issue 4(2021)
• Publication Date: 2021-04
• Subjects: Auditory neuropathy spectrum disorder -- Cochlear implant -- Cochlear implant surgery/complications -- Cochlear implantation -- Electrocochleography -- Enlarged vestibular aqueduct -- Evoked response/methods -- Hearing/physiology -- Intraoperative neurophysiological monitoring/methods -- Pediatric otology -- Tip fold-over; Otology -- Periodicals; Ear -- Diseases -- Periodicals; Skull base -- Surgery -- Periodicals; 617.8005
• DOI: 10.1097/MAO.0000000000003008
• Languages: English
• ISSNs: 1531-7129

Abstract

Abstract : Objective: Tip fold-over is a rare but serious complication of cochlear implant (CI) surgery. The purpose of this study was to present intraoperative electrocochleography (ECochG) observations in a series of CI electrode tip fold-overs. Patients: Five pediatric subjects undergoing CI surgery through a round window (RW) approach with a perimodiolar electrode array, who were diagnosed with either auditory neuropathy spectrum disorder or enlarged vestibular aqueduct. Interventions: Intraoperative RW ECochG during CI surgery: tone burst stimuli were presented from 95 to 110 dB SPL. Main Outcome Measure(s): Magnitude and phase characteristics of ECochG responses obtained intraoperatively before and immediately after electrode insertion were examined for patients with and without tip fold-over. Results: Three subjects presented with tip fold-over and two formed the control group. Among fold-over cases, one participant exhibited an inversion in the starting phase of the cochlear microphonic response and a decrease in spectral magnitude from pre- to postinsertion. Both subjects who did not exhibit a change in phase had an increase in the ECochG-total response (ECochG-TR) magnitude. No case in the control group exhibited a change in starting phase. In regard to the ECochG-TR, all controls showed a decrease in the magnitude. Conclusions: Despite the small number of patients, heterogeneous ECochG response patterns were observed within the fold-over group. Though these results are not conclusive, they can serve as a framework to begin to understand ECochG's utility in detecting intraoperative tip fold-over.