Document Detail

Movements of cochlear implant electrodes inside the cochlea during insertion: an x-ray microscopy study.
MedLine Citation:
PMID:  11875348     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: There are no satisfactory, noninvasive techniques currently available to visualize the cochlear implant (CI) electrode in a dynamic state as it is advanced inside the cochlea. OBJECTIVE: This study describes a radiologic technique that can be used in temporal bones to monitor the electrode position in real time and to visualize the basilar membrane. METHODS: A cochleostomy was performed in accordance with the normal procedure for cochlear implantation in seven fresh cadaveric temporal bones. A special x-ray tube (Microfocus; Focus, Wunstorf, Germany) with a spot size of 1 microm and fluoroscopy were used for continuous videotape imaging of the advancing electrode in the cochlea. Conventional electrodes (MED-EL 40+; MED-EL, Innsbruck, Austria) and prototypes of perimodiolar electrodes (MED-EL), with varying thicknesses and angles of insertion, were used for the study. Finally, contrast liquid (Ultravist; Berlex Imaging, Schering, Germany) was injected into the scala vestibuli through the stapes footplate. RESULTS: The advancing electrode carrier was clearly visible at x20 magnification. With the perimodiolar electrodes, deep insertion was impossible if the guiding wire was too rigid, and retraction occurred if the wire was soft. The intact nature of the basilar membrane could be confirmed by the sequential filling of scala vestibuli and the scala tympani. CONCLUSION: To our knowledge, this is the first noninvasive study demonstrating continuous visualization with high-resolution and x-ray magnification of CI electrode advancement inside the intact cochlea. Our technique can be used for the development of CI electrodes with optimal design characteristics, especially stiffness. Visualization of the basilar membrane will influence the insertion techniques when CIs are developed for patients with residual hearing.
K-B Hüttenbrink; Th Zahnert; C Jolly; G Hofmann
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology     Volume:  23     ISSN:  1531-7129     ISO Abbreviation:  Otol. Neurotol.     Publication Date:  2002 Mar 
Date Detail:
Created Date:  2002-03-04     Completed Date:  2002-06-07     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  100961504     Medline TA:  Otol Neurotol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  187-91     Citation Subset:  IM    
Department of Otorhinolaryngology, University of Technology, Dresden, Germany.
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MeSH Terms
Basilar Membrane / pathology,  radiography
Cochlea / pathology*,  radiography*
Cochlear Implantation*
Electrodes, Implanted
Fluoroscopy / methods

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