title: Effects of steroids and lubricants on electrical impedance and tissue response following cochlear implantation.
abstract: The present study examined the effects of steroids and lubricants on electrical impedance and tissue response following cochlear implantation in animal models. Guinea pigs were implanted following either no treatment, or intrascalar injection with dexamethasone, triamcinolone, sodium hyaluronate or saline. Cats were implanted following either no treatment, or intrascalar injection with dexamethasone, triamcinolone or a mixture of triamcinolone with sodium hyaluronate. In guinea pigs, impedance changes and intracochlear tissue response were less for the hyaluronate and saline groups. In cats, impedance in the dexamethasone group increased similar to non-treated cats. Impedance of triamcinolone treated cats remained low for about two months after implantation, before increasing to levels similar to the other groups. Significant fibrous tissue growth was observed histologically. The results of the present study indicate that a single intracochlear application of hyaluronate or triamcinolone may postpone, but will ultimately not prevent the rise in impedance following cochlear implantation.
authors.affiliation: Co-operative Research Centre for Cochlear Implant and Hearing Aid Innovation, Melbourne, Victoria, Australia.
authors.forename: Christie Qi
authors.initials: CQ
authors.lastname: Huang
authors.forename: Michael
authors.initials: M
authors.lastname: Tykocinski
authors.forename: Dimitra
authors.initials: D
authors.lastname: Stathopoulos
authors.forename: Robert
authors.initials: R
authors.lastname: Cowan
mesh_terms: D000818:Animals; D002415:Cats; D002452:Cell Count; D002921:Cicatrix / Q000473:pathology; D003051:Cochlea / Q000187:drug effects / Q000473:pathology; D003054:Cochlear Implants; D003907:Dexamethasone / Q000494:pharmacology*; D017097:Electric Impedance; D004567:Electrodes, Implanted; D005355:Fibrosis / Q000473:pathology; D005549:Foreign-Body Reaction / Q000473:pathology; D005938:Glucocorticoids / Q000494:pharmacology*; D006168:Guinea Pigs; D006820:Hyaluronic Acid / Q000494:pharmacology*; D065347:Hypromellose Derivatives; D007267:Injections; D054327:Lubricants / Q000494:pharmacology*; D008747:Methylcellulose / Q000031:analogs & derivatives / Q000494:pharmacology; D009925:Organ of Corti / Q000187:drug effects / Q000473:pathology; D011475:Prosthesis Failure; D013136:Spiral Ganglion / Q000187:drug effects / Q000473:pathology; D000267:Tissue Adhesions / Q000473:pathology; D014221:Triamcinolone / Q000494:pharmacology*
chemical_list: D005938:Glucocorticoids; D054327:Lubricants; D014221:Triamcinolone; D065347:Hypromellose Derivatives; D003907:Dexamethasone; D006820:Hyaluronic Acid; D008747:Methylcellulose