title: Extended use of systemic steroid is beneficial in preserving hearing in guinea pigs after cochlear implant.
abstract: CONCLUSIONS
  Seven-day administration of systemic steroids was more effective in preserving hearing for 12 weeks after cochlear implantation (CI) than a 3-day delivery.
  
  
  OBJECTIVE
  To determine the effectiveness of extended delivery of systemic steroids to preserve hearing in guinea pigs after CI.
  
  
  METHODS
  Dexamethasone (4 mg/ml) was delivered parenterally via a mini-osmotic pump for either 3 or 7 days. A dummy CI electrode was inserted via cochleostomy approach in 8-week-old guinea pigs. Auditory thresholds were assessed from tone burst auditory brainstem responses (2, 8, 16, 24, and 32 kHz) at 1 day prior to CI, and 1, 4, and 12 weeks after implantation. Histologic evaluation of the cochleae was carried out.
  
  
  RESULTS
  No differences were observed in hearing thresholds among groups before CI. Significant hearing preservation was achieved at 8, 16, 24, and 32 kHz only in the 7-day infusion group compared with the control group at 1 week after CI. The same trend was maintained at 4 weeks (16, 24 kHz) and 12 weeks (16, 24, and 32 kHz). Histologic review of the 7-day infusion group revealed less fibrosis and ossification in the scala tympani and the preservation of more spiral ganglion cells, compared with the control group.
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , Seoul National University College of Medicine , Seoul , Republic of Korea.|b Department of Otorhinolaryngology-Head and Neck Surgery , Korea University College of Medicine, Korea University Ansan Hospital , Ansan , Republic of Korea.
authors.forename: Yoon Chan
authors.initials: YC
authors.lastname: Rah
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , Seoul National University College of Medicine , Seoul , Republic of Korea.
authors.forename: Min Young
authors.initials: MY
authors.lastname: Lee
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , Seoul National University College of Medicine , Seoul , Republic of Korea.
authors.forename: Shin Hye
authors.initials: SH
authors.lastname: Kim
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , Seoul National University College of Medicine , Seoul , Republic of Korea.
authors.forename: Doo Hee
authors.initials: DH
authors.lastname: Kim
authors.affiliation: c Department of Otolaryngology , University of Melbourne, Royal Victorian Eye and Ear Hospital , Melbourne , Australia.
authors.forename: Hayden
authors.initials: H
authors.lastname: Eastwood
authors.affiliation: c Department of Otolaryngology , University of Melbourne, Royal Victorian Eye and Ear Hospital , Melbourne , Australia.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: O'Leary
authors.affiliation: a Department of Otorhinolaryngology-Head and Neck Surgery , Seoul National University College of Medicine , Seoul , Republic of Korea.
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000818:Animals; D001309:Auditory Threshold / Q000187:drug effects*; D003051:Cochlea / Q000187:drug effects / Q000473:pathology; D019929:Cochlear Implantation; D003907:Dexamethasone / Q000008:administration & dosage*; D004353:Drug Evaluation, Preclinical; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage*; D006168:Guinea Pigs; D006309:Hearing / Q000187:drug effects*; D011182:Postoperative Care
chemical_list: D005938:Glucocorticoids; D003907:Dexamethasone
keywords: Cochlear implant; hearing loss; steroid