Continuous topical drug delivery using osmotic pump in animal cochlear implant model: Continuous steroid delivery is effective for hearing preservation

Abstract

Conclusions: Continuous topical drug delivery using an osmotic pump is an effective supplementary technique for hearing preservation after cochlear implantation, as demonstrated in a guinea pig model. Objective: To evaluate the effect of continuous topical steroid delivery via an osmotic pump in an animal cochlear implant model. Methods: Twenty-three guinea pigs were used for the study. The animals were divided into three groups: control group (n = 8), simple topical dexamethasone delivery group (sDEXA group, n = 7) and continuous topical dexamethasone delivery group (cDEXA, n = 8). The hearing thresholds of all animals were measured by pre-operative auditory brain stem responses (ABRs) at 2, 8, 16, 24, and 32 kHz. ABRs were re-evaluated after cochlear implantation, and the animals were sacrificed for hematoxylin and eosin staining. Results: The ABR threshold at 1 week post-operatively was significantly lower in the cDEXA group than in the control and sDEXA groups at most frequencies. Threshold shifts from baseline were statistically smaller in the cDEXA group than in the control and sDEXA groups at all frequencies. Histological analysis revealed decreased numbers of multi-nucleated giant cells and thinner histiocyte layers.

Keywords:

• Dexamethasone
• cochlear implantation
• topical drug administration
• hearing protection

Acknowledgments

This research was financially supported by The Ministry of Trade, Industry & Energy (MOTIE), and Korea Institute for Advancement of Technology (KIAT) and Daegyeong Institute for Regional Program Evaluation (DGIRPE) through the Leading Industry Development for Economic Region. The Industrial Strategic Technology Development Program, 10047943, Development of Micro-surgical Apparatus based on 3D Tomographic Operating Microscope’ funded by the Ministry of Trade, Industry & Energy (MI, Korea) (No. 10047943).

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.