title: Scalar localization by cone-beam computed tomography of cochlear implant carriers: a comparative study between straight and periomodiolar precurved electrode arrays.
abstract: OBJECTIVE
  To compare the incidence of dislocation of precurved versus straight flexible cochlear implant electrode arrays using cone-beam computed tomography (CBCT) image analyses.
  
  
  METHODS
  Consecutive nonrandomized case-comparison study.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  Analyses of patients' CBCT images after cochlear implant surgery.
  
  
  METHODS
  Precurved and straight flexible electrode arrays from two different manufacturers were implanted. A round window insertion was performed in most cases. Two cases necessitated a cochleostomy. The patients' CBCT images were reconstructed in the coronal oblique, sagittal oblique, and axial oblique section.
  
  
  METHODS
  The insertion depth angle and the incidence of dislocation from the scala tympani to the scala vestibuli were determined.
  
  
  RESULTS
  The CBCT images and the incidence of dislocation were analyzed in 54 patients (61 electrode arrays). Thirty-one patients were implanted with a precurved perimodiolar electrode array and 30 patients with a straight flexible electrode array. A total of nine (15%) scalar dislocations were observed in both groups. Eight (26%) scalar dislocations were observed in the precurved array group and one (3%) in the straight array group. Dislocation occurred at an insertion depth angle between 170 and 190 degrees in the precurved array group and at approximately 370 degrees in the straight array group.
  
  
  CONCLUSIONS
  With precurved arrays, dislocation usually occurs in the ascending part of the basal turn of the cochlea. With straight flexible electrode arrays, the incidence of dislocation was lower, and it seems that straight flexible arrays have a higher chance of a confined position within the scala tympani than perimodiolar precurved arrays.
authors.affiliation: *Joseph Fourier University-Grenoble 1; †Department of Otorhinolaryngology, University Hospital of Grenoble; ‡Department of Radiology, University Hospital, CHU Grenoble; and §Groupe Clinique du Mail, Grenoble; and ∥Radiologie Clinique Pasteur, Toulouse, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Boyer
authors.forename: Alexandre
authors.initials: A
authors.lastname: Karkas
authors.forename: Arnaud
authors.initials: A
authors.lastname: Attye
authors.forename: Virginie
authors.initials: V
authors.lastname: Lefournier
authors.forename: Bernard
authors.initials: B
authors.lastname: Escude
authors.forename: Sebastien
authors.initials: S
authors.lastname: Schmerber
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002648:Child; D003051:Cochlea / Q000000981:diagnostic imaging* / Q000601:surgery; D019929:Cochlear Implantation / Q000379:methods; D003054:Cochlear Implants; D054893:Cone-Beam Computed Tomography; D005260:Female; D034381:Hearing Loss / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D012533:Scala Tympani / Q000000981:diagnostic imaging*; D054738:Scala Vestibuli / Q000000981:diagnostic imaging*; D016896:Treatment Outcome; D055815:Young Adult