title: Tip Fold-over in Cochlear Implantation: Case Series.
abstract: To describe the incidence, clinical presentation, and performance of cochlear implant (CI) recipients with tip fold-over.
  
  
  
  Retrospective case series.
  
  
  
  Tertiary referral center.
  
  
  
  CI recipients who underwent postoperative computed tomography (CT) scanning.
  
  
  
  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.
  
  
  
  Location of the fold-over; audiological performance pre and postselective deactivation of fold-over electrodes.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: *Department of Otolaryngology Head and Neck Surgery †Department of Hearing and Speech Sciences ‡Department of Electrical Engineering and Computer Science, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: M Geraldine
authors.initials: MG
authors.lastname: Zuniga
authors.forename: Alejandro
authors.initials: A
authors.lastname: Rivas
authors.forename: Andrea
authors.initials: A
authors.lastname: Hedley-Williams
authors.forename: Rene H
authors.initials: RH
authors.lastname: Gifford
authors.forename: Robert
authors.initials: R
authors.lastname: Dwyer
authors.forename: Benoit M
authors.initials: BM
authors.lastname: Dawant
authors.forename: Linsey W
authors.initials: LW
authors.lastname: Sunderhaus
authors.forename: Kristen L
authors.initials: KL
authors.lastname: Hovis
authors.forename: George B
authors.initials: GB
authors.lastname: Wanna
authors.forename: Jack H
authors.initials: JH
authors.lastname: Noble
authors.forename: Robert F
authors.initials: RF
authors.lastname: Labadie
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003051:Cochlea / Q000000981:diagnostic imaging / Q000601:surgery*; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D005260:Female; D006309:Hearing; D034381:Hearing Loss / Q000000981:diagnostic imaging / Q000601:surgery*; D006320:Hearing Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012086:Reoperation; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult