title: Insertion depth impacts speech perception and hearing preservation for lateral wall electrodes.
abstract: 1) Examine angular insertion depths (AID) and scalar location of Med-El (GmbH Innsbruck, Austria) electrodes; and 2) determine the relationship between AID and audiologic outcomes controlling for scalar position.
  
  
  
  Retrospective review.
  
  
  
  Postlingually deafened adults undergoing cochlear implantation with Flex 24, Flex 28, and Standard electrode arrays (Med-El) were identified. Patients with preoperative and postoperative computed tomography scans were included so that electrode location and AID could be determined. Outcome measures were 1) speech perception in the cochlear implant (CI)-only condition, and 2) short-term hearing preservation.
  
  
  
  Forty-eight implants were included; all electrodes (48 of 48) were positioned entirely within the scala tympani. The median AID was 408° (interquartile [IQ] range 373°-449°) for Flex 24, 575° (IQ range 465°-584°) for Flex 28, and 584° (IQ range 368°-643°) for Standard electrodes (Med-El). The mean postoperative CNC score was 43.7% ± 21.9. A positive correlation was observed between greater AID and better CNC performance (r = 0.48, P < 0.001). Excluding patients with postoperative residual hearing, a strong correlation between AID and CNC persisted (r = 0.57, P < 0.001). In patients with preoperative residual hearing, mean low-frequency pure-tone average (PTA) shift was 27 dB ± 14. A correlation between AID and low-frequency PTA shift at activation was noted (r = 0.41, P = 0.04).
  
  
  
  Favorable rates of scala tympani insertion (100%) were observed. In the CI-only condition, a direct correlation between greater AID and CNC score was noted regardless of postoperative hearing status. Deeper insertions were, however, associated with worse short-term hearing preservation. When patients without postoperative residual hearing were analyzed independently, the relationship between greater insertion depth and better performance was strengthened.
  
  
  
  4. Laryngoscope, 127:2352-2357, 2017.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: Brendan P
authors.initials: BP
authors.lastname: O'Connell
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Hunter
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: David S
authors.initials: DS
authors.lastname: Haynes
authors.affiliation: Department of Hearing and Speech Sciences, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: Jourdan T
authors.initials: JT
authors.lastname: Holder
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: Matt M
authors.initials: MM
authors.lastname: Dedmon
authors.affiliation: Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: Jack H
authors.initials: JH
authors.lastname: Noble
authors.affiliation: Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: Benoit M
authors.initials: BM
authors.lastname: Dawant
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University, Nashville, Tennessee, U.S.A.
authors.forename: George B
authors.initials: GB
authors.lastname: Wanna
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D005260:Female; D006309:Hearing / Q000502:physiology*; D046088:Hearing Loss, Unilateral / Q000503:physiopathology / Q000534:rehabilitation*; D006320:Hearing Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012533:Scala Tympani / Q000000981:diagnostic imaging / Q000601:surgery*; D013067:Speech Perception / Q000502:physiology*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: Cochlear implant; Flex 24; Flex 28; audiologic outcomes; electrode location; scalar translocation; speech perception