Related Experiment Videos
Viscoelastic properties of rabbit vocal folds after augmentation
Stellan Hertegård1, Ake Dahlqvist, Claude Laurent
1Department of Logopedics and Phoniatrics, Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden. stellan.hertegard@klinvet.ki.se
Background:
Vocal fold function is closely related to tissue viscoelasticity. Augmentation substances may alter the viscoelastic properties of vocal fold tissues and hence their vibratory capacity.
Objectives:
We sought to investigate the viscoelastic properties of rabbit vocal folds in vitro after injections of various augmentation substances.
Study Design And Setting:
Polytetrafluoroethylene (Teflon), cross-linked collagen (Zyplast), and cross-linked hyaluronan, hylan b gel (Hylaform) were injected into the lamina propria and the thyroarytenoid muscle of rabbit vocal folds. Dynamic viscosity of the injected vocal fold as a function of frequency was measured with a Bohlin parallel-plate rheometer during small-amplitude oscillation.
Results:
All injected vocal folds showed a decreasing dynamic viscosity with increasing frequency. Vocal fold samples injected with hylan b gel showed the lowest dynamic viscosity, quite close to noninjected control samples. Vocal folds injected with polytetrafluoroethylene showed the highest dynamic viscosity followed by the collagen samples.
Conclusions:
The data indicated that hylan b gel in short-term renders the most natural viscoelastic properties to the vocal fold among the substances tested. This is of importance to restore/preserve the vibratory capacity of the vocal folds when glottal insufficiency is treated with injections.