Tolerability and Safety of a Poly-L-Lactide Eustachian Tube Stent Using a Chinchilla Animal Model

Objective: To present the design for a novel, resorbable, drug-eluting Eustachian-tube stent and to ascertain its tolerability and resorption in a chinchilla animal model. Materials and Methods: In a prospective, controlled animal study, a poly-l-lactide stent was implanted via a transbullar approach in one Eustachian tube (ear implanted was randomly selected) of five adult female chinchillas. The other ear served as a matched control. Otoendoscopy was performed at baseline to rule out pre-existing disease. Animals were sacrificed at varying times up to 26 weeks post implantation. Blinded histological sectioning was performed to determine degree of inflammatory response and stent resorption. All adverse events were recorded. Results: Follow-up data were available for three animals at the time of sacrifice. The histologic findings were similar for the test and control ears. The stents did not appreciably resorb over the 6-month period of follow-up. Conclusions: The poly-l-lactide Eustachian tube stent generally was well tolerated by the chinchillae without untowards effects. A follow-up larger sample animal study using another animal model with a larger Eustachian tube (a healthy Eustachian tube in one ear and a non-opening Eustachian tube in the other ear) is planned to further establish a safety profile, to investigate efficacy outcomes, and to follow gas-sterilized stents overtime towards complete resorption.