title: Effects of intraoperatively applied glucocorticoid hydrogels on residual hearing and foreign body reaction in a guinea pig model of cochlear implantation.
abstract: CONCLUSIONS
  The intraoperative application of glucocorticoid-loaded hydrogels seems to cause a reduction in neutrophil infiltration. No beneficial effect on hearing thresholds was detected.
  
  
  OBJECTIVE
  To evaluate the application of dexamethasone- and triamcinolone acetonide-loaded hydrogels for effects on hearing preservation and foreign body reaction in a guinea pig model for cochlear implantation (CI).
  
  
  METHODS
  A total of 48 guinea pigs (n = 12 per group) were implanted with a single channel electrode and intraoperatively treated with 50 μl of a 20% w/v poloxamer 407 hydrogel loaded with 6% dexamethasone or 30% triamcinolone acetonide, a control hydrogel, or physiological saline. Click- and tone burst-evoked compound action potential thresholds were determined preoperatively and directly postoperatively as well as on days 3, 7, 14, 21, and 28. At the end of the experiment, temporal bones were prepared for histological evaluation by a grinding/polishing technique with the electrode in situ. Three ears per treatment group were serially sectioned and evaluated for histological alterations.
  
  
  RESULTS
  The intratympanic application of glucocorticoid-loaded hydrogels did not improve the preservation of residual hearing in this cochlear implant model. The foreign body reaction to the electrode appeared reduced in the glucocorticoid-treated animals. No correlation was found between the histologically described trauma to the inner ear and the resulting hearing threshold shifts.
authors.affiliation: Department of Otorhinolaryngology, Medical University of Vienna.
authors.forename: Clemens
authors.initials: C
authors.lastname: Honeder
authors.forename: Lukas David
authors.initials: LD
authors.lastname: Landegger
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Engleder
authors.forename: Franz
authors.initials: F
authors.lastname: Gabor
authors.forename: Roberto
authors.initials: R
authors.lastname: Plasenzotti
authors.forename: Hanns
authors.initials: H
authors.lastname: Plenk
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kaider
authors.forename: Lena
authors.initials: L
authors.lastname: Hirtler
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Gstoettner
authors.forename: Christoph
authors.initials: C
authors.lastname: Arnoldner
mesh_terms: D000200:Action Potentials; D000818:Animals; D003051:Cochlea / Q000187:drug effects / Q000473:pathology / Q000601:surgery; D019929:Cochlear Implantation; D003054:Cochlear Implants / Q000009:adverse effects; D003907:Dexamethasone / Q000008:administration & dosage; D004195:Disease Models, Animal; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D005549:Foreign-Body Reaction / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D005938:Glucocorticoids / Q000008:administration & dosage*; D006168:Guinea Pigs; D006309:Hearing / Q000187:drug effects*; D020100:Hydrogels; D007430:Intraoperative Care; D008297:Male; D020556:Neutrophil Infiltration; D014222:Triamcinolone Acetonide / Q000008:administration & dosage
chemical_list: D005938:Glucocorticoids; D020100:Hydrogels; D003907:Dexamethasone; D014222:Triamcinolone Acetonide
keywords: Cochlear implant; glucocorticoid; hearing preservation