| Preventing hearing damage using topical dexamethasone during reversible cochlear ischemia: an animal model. | |
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MedLine Citation:
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PMID: 19638939 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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HYPOTHESIS: Local application of dexamethasone to the round window (RW) niche prevents cochlear damage caused by local reversible ischemia. BACKGROUND: Cochlear ischemia induced by internal auditory artery (IAA) compression/stretching is thought to cause postoperative sensory hearing loss after attempted hearing preservation removal of acoustic neuroma tumors. Dexamethasone administered to the RW niche traveling through the membrane to the cochlear fluids may prevent ischemic damage. MATERIALS AND METHODS: Ten young albino rabbits were used for this study. Ischemic episodes were induced by compressing the IAA. Laser Doppler cochlear blood flow was measured using a probe positioned at the RW niche. Transtympanic electrocochleography was measured at 4, 8, and 12 kHz. In 5 test ears, dexamethasone was administered topically at the RW for approximately 50 minutes before the IAA compressions, whereas in 5 control ears, saline was applied in the same way. Each ear underwent one 10-minute IAA compression with a 60-minute postischemic period of transtympanic electrocochleography monitoring. RESULTS: In both control- and dexamethasone-treated ears, ischemic episodes measured by Laser Doppler cochlear blood flow were comparable. Fifty minutes after IAA decompression, in dexamethasone-pretreated ears, cochlear microphonic and compound action potential amplitudes at all test frequencies were 10 to 15% less reduced than those in control ears. Compound action potential latencies in dexamethasone-pretreated ears resulted in shorter latency delay than in control ears. CONCLUSION: The RW seems to be an efficacious route for the administration of dexamethasone into the inner ear. Dexamethasone showed a protective effect on cochlear function after local ischemia. Transtympanic electrocochleography was found to be a sufficient and effective tool in monitoring hearing. |
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Authors:
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Krzysztof Morawski; Fred F Telischi; Jorge Bohorquez; Kazimierz Niemczyk |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural |
Journal Detail:
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Title: Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology Volume: 30 ISSN: 1537-4505 ISO Abbreviation: Otol. Neurotol. Publication Date: 2009 Sep |
Date Detail:
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Created Date: 2009-08-25 Completed Date: 2009-11-16 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100961504 Medline TA: Otol Neurotol Country: United States |
Other Details:
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Languages: eng Pagination: 851-7 Citation Subset: IM |
Affiliation:
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Department of Otolaryngology, Medical University of Warsaw, Warsaw, Poland. morawski@neurotology.pl |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Administration, Topical Animals Anti-Inflammatory Agents / administration & dosage, therapeutic use* Audiometry, Evoked Response Cochlea / blood supply* Cochlear Diseases / complications, drug therapy* Dexamethasone / administration & dosage, therapeutic use* Hearing Loss / etiology, prevention & control* Ischemia / drug therapy Laser-Doppler Flowmetry Rabbits Regional Blood Flow / drug effects Reperfusion Injury / prevention & control |
| Grant Support | |
ID/Acronym/Agency:
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2R 44 DC 04344-02/DC/NIDCD NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Anti-Inflammatory Agents; 50-02-2/Dexamethasone |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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