Rheological characterization of vocal fold after injection augmentation in a preliminary animal study

The investigation of vocal folds viscoelastic properties in an animal model (rabbit) after injection of various augmentation substances, 6 months after injection, is reported. The injected materials were: hyaluronan-based materials (Hylan B gel and Deflux®), cross-linked collagen (Zyplast®) and polytetrafluoroethylene (Teflon®). Rheological properties of the augmentation substances were also evaluated. The results from these animal experiments indicate that the viscoelastic properties of the vocal folds injected with Deflux®, Zyplast® and Hylan B gel are similar to the healthy vocal folds (non-injected samples) used as control, thus demonstrating that these materials are good candidates for further studies aimed at restoring/preserving the vibratory capacity of the vocal folds with injection treatment in glottal insufficiency.