Article
Steroid-induced Reduction of Impedance after Cochlear Implantation is Maintained for Several Years
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Published: | May 31, 2005 |
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Outline
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Introduction
The objective of this study was to investigate the long term effect of intraoperative application of steroid suspension and coating of the electrode contacts with a thin film of iridiumoxide on the intracochlear impedance development in adults implanted with the Nucleus 24 Contour electrode.
Materials and Methods
The development of intra-cochlear impedances was investigated in four different groups of adult patients for two or more years postoperatively. The four groups were: a) standard Nucleus 24 Contour (control), b) standard Nucleus 24 Contour with intra-operative application of steroids, c) Iridium-coated Nucleus 24 Contour, and d) Iridium-coated Nucleus 24 Contour with intra-operative application of steroids.
Results
The previously reported reduction of impedances during the first weeks after intraoperative application of steroids was found to be maintained over several years postoperatively. Application of steroids also reduced the postoperative impedance with iridium-coated electrode contacts even though this reduction was not significant. Iridium coating of the electrode contacts itself did not show a reduction effect.
Conclusions
As the reduction of electrode impedances with application of steroids is persisting, intracochlear application of steroids can be considered on a regular basis whereas iridium coating could not be proved beneficial under the applied test conditions.