title: Depth of Cochlear Implant Array Within the Cochlea and Performance Outcome.
abstract: OBJECTIVE
  To evaluate whether the depth of cochlear implant array within the cochlea affects performance outcomes 1 year following cochlear implantation.
  
  
  METHODS
  A retrospective case review of 120 patients who were implanted with the Advanced Bionics HiFocus 1J. Post-implantation plain-radiographs were retrospectively reviewed, and the depth of insertion was measured in degrees from the round window to the electrode tip. Correlation between the depth of insertion and 1-year post-activation Hearing in Noise Test (HINT) scores was analyzed. Intrascala position was not assessed.
  
  
  RESULTS
  Depth of electrode insertion ranged from 180° to 720°, and HINT scores ranged from 0% to 100%. A Mann-Whitney U test demonstrated significantly improved 1-year post-activation HINT scores in patients with an insertion depth of 360° or more in comparison with patients with insertion depth of less than 360° (81% vs 61%, P = .048). Patients with 13 to 15 contacts within cochlear turns performed as well as patients with full insertion of all 16 contacts, while patients with only 12 contacts performed poorly.
  
  
  CONCLUSIONS
  Insertion depth of the AB HiFocus 1J electrode of less than 360° is associated with reduced 1-year post-activation HINT scores when compared with deeper insertions. Partial insertion of 13 active contacts or more led to similar results as full insertion.
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto. ON, Canada Department of Otolaryngology and Head and Neck Surgery, Rabin Medical Center, Tel Aviv University, Tel Aviv, Israel ohadhilly@yahoo.com.
authors.forename: Ohad
authors.initials: O
authors.lastname: Hilly
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto. ON, Canada.
authors.forename: Leah
authors.initials: L
authors.lastname: Smith
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto. ON, Canada.
authors.forename: Euna
authors.initials: E
authors.lastname: Hwang
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto. ON, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Shipp
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto. ON, Canada Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto. ON, Canada.
authors.forename: Sean
authors.initials: S
authors.lastname: Symons
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto. ON, Canada.
authors.forename: Julian M
authors.initials: JM
authors.lastname: Nedzelski
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto. ON, Canada.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Chen
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto. ON, Canada.
authors.forename: Vincent Y W
authors.initials: VY
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D004567:Electrodes, Implanted; D005260:Female; D034381:Hearing Loss / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009622:Noise; D011859:Radiography; D012189:Retrospective Studies; D012405:Round Window, Ear / Q000000981:diagnostic imaging; D013067:Speech Perception; D016896:Treatment Outcome
keywords: cochlear implant trials; cochlear implantation; depth of insertion; hearing in noise test; outcome