Impedance Changes and Fibrous Tissue Growth after Cochlear Implantation Are Correlated and Can Be Reduced Using a Dexamethasone Eluting Electrode

Autor: Roland Hessler, Maciej Wilk, Kenneth Mugridge, Thomas Lenarz, Michael Fehr, Verena Scheper, Claude Jolly
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Electrical Stimulation
lcsh:Medicine
Otology
Deafness
Dexamethasone
0302 clinical medicine
Fibrosis
Electric Impedance
Medicine and Health Sciences
Electrochemistry
030223 otorhinolaryngology
lcsh:Science
Hearing Disorders
Multidisciplinary
Pharmaceutics
Chemistry
Anatomy
Cochlear Implantation
Electrodes
Implanted
Cochlea
Sound
medicine.anatomical_structure
Connective Tissue
Standard electrode potential
Inner Ear
Physical Sciences
Electrode
Female
Research Article
medicine.drug
Guinea Pigs
Connective tissue
Surgical and Invasive Medical Procedures
03 medical and health sciences
Evoked Potentials
Auditory
Brain Stem
medicine
Electrode array
Animals
Hearing Loss
Round window
Electrode Potentials
lcsh:R
Biology and Life Sciences
Auditory Threshold
Scala Tympani
medicine.disease
Electric Stimulation
Cochlear Implants
Biological Tissue
Round Window
Ear
Otorhinolaryngology
Ears
lcsh:Q
Drug Delivery
Head
030217 neurology & neurosurgery
Developmental Biology
Biomedical engineering
Zdroj: PLoS ONE, Vol 11, Iss 2, p e0147552 (2016)
PLoS ONE
ISSN: 1932-6203
Popis: Background The efficiency of cochlear implants (CIs) is affected by postoperative connective tissue growth around the electrode array. This tissue formation is thought to be the cause behind post-operative increases in impedance. Dexamethasone (DEX) eluting CIs may reduce fibrous tissue growth around the electrode array subsequently moderating elevations in impedance of the electrode contacts. Methods For this study, DEX was incorporated into the silicone of the CI electrode arrays at 1% and 10% (w/w) concentration. Electrodes prepared by the same process but without dexamethasone served as controls. All electrodes were implanted into guinea pig cochleae though the round window membrane approach. Potential additive or synergistic effects of electrical stimulation (60 minutes) were investigated by measuring impedances before and after stimulation (days 0, 7, 28, 56 and 91). Acoustically evoked auditory brainstem responses were recorded before and after CI insertion as well as on experimental days 7, 28, 56, and 91. Additionally, histology performed on epoxy embedded samples enabled measurement of the area of scala tympani occupied with fibrous tissue. Results In all experimental groups, the highest levels of fibrous tissue were detected in the basal region of the cochlea in vicinity to the round window niche. Both DEX concentrations, 10% and 1% (w/w), significantly reduced fibrosis around the electrode array of the CI. Following 3 months of implantation impedance levels in both DEX-eluting groups were significantly lower compared to the control group, the 10% group producing a greater effect. The same effects were observed before and after electrical stimulation. Conclusion To our knowledge, this is the first study to demonstrate a correlation between the extent of new tissue growth around the electrode and impedance changes after cochlear implantation. We conclude that DEX-eluting CIs are a means to reduce this tissue reaction and improve the functional benefits of the implant by attenuating electrode impedance.
Databáze: OpenAIRE
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