Use of pyrolytic carbon coated beads (Durasphere) to treat glottic failure: an experimental study in dogs

There is no ideal tissue or substance to be injected in the vocal folds. The objective of the present study was to assess the use of Durasphere in canine vocal fold injection.

in six adult dogs we injected 0.3 mL of Durasphere in the middle third of the thyroarytenoid muscle and 0.3 mL of saline solution in the contralateral vocal fold. The animals were slaughtered after seven days (three dogs) and after 90 days (three dogs). We analyzed the inflammatory process in the vocal fold and in the lamina propria of the vocal folds.

in the vocal muscle which received Durasphere there was a significantly more intense inflammation when compared to the control muscle--there was a moderate lymphomodular infiltrate after seven days and mild after 90 days. We did not observe foreign bodies nor granulomas. On the lamina propria there was a mild inflammatory process in the two groups, without difference between them.

this is a substance of proven biocompatibility in humans, with preliminary and unprecedented results and its injection in canine vocal folds caused a moderate inflammatory process after seven days and mild after 90 days, without foreign bodies or granuloma formation.