Histopathological and audiological effects of mechanical trauma associated with the placement of an intracochlear electrode, and the benefit of corticosteroid infusion: prospective animal study

Abstract

The findings suggest that continuous dexamethasone infusion is beneficial for preventing the loss of hair cells and neurons associated with early and late periods of intracochlear electrode trauma.

Effects of a dexamethasone-releasing implant on cochleae: A functional, morphological and pharmacokinetic study

“…ABR thresholds, DPOAE amplitude, and DPOAE thresholds consistently indicated hearing loss in all frequencies immediately after the electrode insertion in the present study. This acute hearing impairment is consistent with the findings of previous studies Lee et al, 2013;Burghard et al, 2014;Malkoc et al, 2014).…”

“…Sustained perfusion of dexamethasone via an osmotic pump into the cochlea for 8 days after cochlear implantation demonstrated a considerable recovery of ABR thresholds in guinea pigs (Eshraghi et al, 2007). Continuous infusion for 14 days after cochlear implantation suggested a benefit for the prevention of hair cell loss (Malkoc et al, 2014). Astolfi et al (2014) summarized three main phases of damage caused by cochlear implantation: (1) insertion trauma within the first 2 days, (2) inflammation within 2 weeks, and (3) an intracochlear chronic fibrosis reaction.…”

Long-Term in vivo Release Profile of Dexamethasone-Loaded Silicone Rods Implanted Into the Cochlea of Guinea Pigs

“…Many experimental studies in animals have demonstrated that the use of corticosteroids is able to preserve hearing thresholds, increase the survival of hair cells and spiral ganglia, and decrease the formation of new fibrotic tissue within implanted cochlea (20)(21)(22)(23)(24)(25)(26)(27). Clinical studies demonstrate lower impedances and improved preservation of low-frequency residual hearing in patients when corticosteroids are used in CI surgery (28)(29)(30)(31)(32)(33)(34).…”

Metabolic reprogramming of inner ear cell line HEI-OC1 after dexamethasone application

“…Synthetic glucocorticoids were first synthesized in 1957 and approved for medical use in 1961. Animal testing has shown that the use of glucocorticoids dampens foreign body reactions; consequently, the survival of hair cells and spiral ganglions is increased and fibrosis reduced (Eshraghi et al, 2007 ; Kuthubutheen et al, 2015 ; Malkoc et al, 2014 ). The first clinical pilot studies indicated that the use of glucocorticoids in cochlear implant surgery could prevent increased electrical impedance, improving preservation of the dynamic range (Bas et al, 2016 ; Kuthubutheen et al, 2017 ; Prenzler et al, 2018 ).…”