Abstract | UNLABELLED: To study electric acoustic stimulation, we have developed a model of guinea pig cochlear implantation via a cochleostomy. Thirty minutes prior to implantation, a hyaluronic acid/ carboxymethylcellulose bead, loaded with either dexamethasone or normal saline, was placed upon the round window membrane. Animals that did not receive beads acted as controls. Pure-tone auditory brainstem response thresholds were estimated before and after electrode insertion, and 1 and 4 weeks later. Selected cochlear histology was performed. RESULTS:
Dexamethasone could be detected in the cochlea for 24 h after cochlear implantation. Thresholds were elevated across frequencies in all animals immediately after surgery. These thresholds recovered completely at and below 2 kHz, and partially at higher frequencies by 1 week after implantation. At 32 kHz, but not the lower frequencies, the presence of dexamethasone had a significant protective effect upon hearing, which increased in magnitude over time. The protection was greatest in difficult implantations where an intractable resistance to electrode insertion was met. There was a persistent foreign body reaction at the site of implantation of saline-treated implanted ears but not in the dexamethasone-treated implanted ears. CONCLUSION: Short-term preoperative delivery of dexamethasone through the round window can protect residual hearing during cochlear implantation, especially during technically difficult surgery.
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Authors | David P James, Hayden Eastwood, Rachael T Richardson, Stephen J O'Leary |
Journal | Audiology & neuro-otology
(Audiol Neurootol)
Vol. 13
Issue 2
Pg. 86-96
( 2008)
ISSN: 1421-9700 [Electronic] Switzerland |
PMID | 18057872
(Publication Type: Journal Article)
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Copyright | (c) 2007 S. Karger AG, Basel |
Chemical References |
- Adrenal Cortex Hormones
- Dexamethasone
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Topics |
- Adrenal Cortex Hormones
(pharmacology)
- Animals
- Audiometry, Pure-Tone
- Cochlear Implantation
- Dexamethasone
(pharmacology)
- Evoked Potentials, Auditory, Brain Stem
(physiology)
- Guinea Pigs
- Hearing
(drug effects)
- Postoperative Complications
- Round Window, Ear
(drug effects)
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