Introduction:
Steroids can reduce foreign body reaction and excessive scarring. The extent of connective
tissue growth around the cochlear implant (CI) electrode correlates with the postoperatively
measurable impedances. In previous studies, it was possible to achieve a concentration-dependent
lowering of the impedances by intracochlear triamcinolone injection using a specially
designed cochlear catheter also in apical areas of the cochlea. In order to evaluate
the sustainability of this effect, the patients were tracked accordingly and long-term
data were evaluated.
Materials and Methods:
5 patients without functional residual hearing with triamcinolone (low dose: 4 mg/ml
vs. high dose: 20 mg/ml) were treated with a cochlear catheter before implantation
with a Med-El Flex 28 electrode. Impedances and Electrically Evoked Compound Action
Potentials as well as the Amplitude Growth Function were measured at defined times
and compared with a control group with the same electrode, similar residual hearing
but without catheter application.
Results:
Undesirable effects were not recorded. While in the low dose group the impedances
decreased only in the first weeks compared to the control group, the effect in the
high dose group was detectable both basal and apical until after first fit. In all
subsequent measurements thereafter, there were no significant differences between
the groups. Functional results were also comparable.
Conclusion:
Deep intracochlear administration of triamcinolone with a cochlear catheter provides
a concentration-dependent, transient decrease in impedance. This effect was detectable
even at high doses only until after first fit.
