title: Insertion of Cochlear Implant Electrode Array Using the Underwater Technique for Preserving Residual Hearing.
abstract: OBJECTIVE
  To describe a method of cochlear implantation in which the opening of the cochlea and the electrode array insertion are performed under water (underwater technique).
  
  
  METHODS
  Retrospective patient review.
  
  
  METHODS
  Academic tertiary referral center.
  
  
  METHODS
  Fifteen implantations in children and adult patients with residual hearing at the frequencies 250, 500, and 1000 Hz on the unaided preoperative pure-tone audiometry were included in this study.
  
  
  METHODS
  Cochlear implantation with a conventional full-length electrode, in which the opening of the cochlea and the electrode array insertion are performed after the tympanic cavity was filled with body-temperature Ringer solution.
  
  
  METHODS
  Changes on residual hearing 6 to 8 weeks after surgery and at subsequent follow-up appointments were analyzed. Preservation of residual hearing was defined as measurable postoperative threshold at the frequencies 250, 500, and 1000 Hz.
  
  
  RESULTS
  Overall postimplant hearing preservation 6 to 8 weeks after implantation was achieved in 13 of the patients (87%). Subsequent follow-up was performed on average 15.2 months after surgery (range, 7-32) in 14 out of 15 patients. At this late postoperative evaluation preservation of hearing was recorded in nine patients (64%), whereas in the remaining five patients (36%) no residual hearing was measured.
  
  
  CONCLUSIONS
  The underwater technique offers a reliable nontraumatic method for electrode array insertions during cochlear implantation. The method respects the physiology of the cochlea und minimizes the pressure variations during cochlear opening and implantation.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Anagiotos
authors.forename: Dirk
authors.initials: D
authors.lastname: Beutner
authors.forename: Antoniu-Oreste
authors.initials: AO
authors.lastname: Gostian
authors.forename: David
authors.initials: D
authors.lastname: Schwarz
authors.forename: Jan-Christoffer
authors.initials: JC
authors.lastname: Luers
authors.forename: Karl-Bernd
authors.initials: KB
authors.lastname: Hüttenbrink
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone; D002648:Child; D002675:Child, Preschool; D003051:Cochlea / Q000601:surgery*; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult