Wednesday, April 23rd, 2014

Assessment of Canine Vocal Fold Function After Injection of a New Biomaterial Designed to Treat Phonatory Mucosal Scarring
Authors:  Sandeep S. Karajanagi, PhD; Gerardo Lopez-Guerra, MD; Hyoungshin Park, PhD; James B. Kobler, PhD; Marilyn Galindo; Jon Aanestad; Daryush D. Mehta, PhD; Yoshihiko Kumai, MD, PhD; Nicholas Giordano; Anthony d’Almeida; James T. Heaton, PhD; Robert Langer, ScD; Victoria L. M. Herrera, MD; William Faquin, MD, PhD; Robert E. Hillman, PhD; Steven M. Zeitels, MD
  Objectives: Most cases of irresolvable hoarseness are due to deficiencies in the pliability and volume of the superficial lamina propria of the phonatory mucosa. By using a US Food and Drug Administration–approved polymer, polyethylene glycol (PEG), we created a novel hydrogel (PEG30) and investigated its effects on multiple vocal fold structural and functional parameters.
Methods: We injected PEG30 unilaterally into 16 normal canine vocal folds with survival times of 1 to 4 months. Highspeed videos of vocal fold vibration, induced by intratracheal airflow, and phonation threshold pressures were recorded at 4 time points per subject. Three-dimensional reconstruction analysis of 11.7 T magnetic resonance images and histologic analysis identified 3 cases wherein PEG30 injections were the most superficial, so as to maximally impact vibratory function. These cases were subjected to in-depth analyses.
Results: High-speed video analysis of the 3 selected cases showed minimal to no reduction in the maximum vibratory amplitudes of vocal folds injected with PEG30 compared to the non-injected, contralateral vocal fold. All PEG30-injected vocal folds displayed mucosal wave activity with low average phonation threshold pressures. No significant inflammation was observed on microlaryngoscopic examination. Magnetic resonance imaging and histologic analyses revealed time-dependent resorption of the PEG30 hydrogel by phagocytosis with minimal tissue reaction or fibrosis.
Conclusions: The PEG30 hydrogel is a promising biocompatible candidate biomaterial to restore form and function to deficient phonatory mucosa, while not mechanically impeding residual endogenous superficial lamina propria.
(Ann Otol Rhinol Laryngol 2011;120:175-184.)
Keywords:  hoarseness, hydrogel, polyethylene glycol, scar
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