title: Assessment of canine vocal fold function after injection of a new biomaterial designed to treat phonatory mucosal scarring.
abstract: OBJECTIVE
  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. High-speed 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.
authors.affiliation: Department of Surgery, Center for Laryngeal Surgery and Voice Rehabilitation, Massachusetts General Hospital, Boston, MA 02114, USA.
authors.forename: Sandeep S
authors.initials: SS
authors.lastname: Karajanagi
authors.forename: Gerardo
authors.initials: G
authors.lastname: Lopez-Guerra
authors.forename: Hyoungshin
authors.initials: H
authors.lastname: Park
authors.forename: James B
authors.initials: JB
authors.lastname: Kobler
authors.forename: Marilyn
authors.initials: M
authors.lastname: Galindo
authors.forename: Jon
authors.initials: J
authors.lastname: Aanestad
authors.forename: Daryush D
authors.initials: DD
authors.lastname: Mehta
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kumai
authors.forename: Nicholas
authors.initials: N
authors.lastname: Giordano
authors.forename: Anthony
authors.initials: A
authors.lastname: d'Almeida
authors.forename: James T
authors.initials: JT
authors.lastname: Heaton
authors.forename: Robert
authors.initials: R
authors.lastname: Langer
authors.forename: Victoria L M
authors.initials: VL
authors.lastname: Herrera
authors.forename: William
authors.initials: W
authors.lastname: Faquin
authors.forename: Robert E
authors.initials: RE
authors.lastname: Hillman
authors.forename: Steven M
authors.initials: SM
authors.lastname: Zeitels
mesh_terms: D000818:Animals; D004285:Dogs; D004548:Elasticity; D005355:Fibrosis; D020100:Hydrogels / Q000494:pharmacology*; D007267:Injections; D007820:Laryngeal Mucosa / Q000187:drug effects*; D007828:Laryngoscopy; D007830:Larynx / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D023421:Models, Animal; D010587:Phagocytosis; D010699:Phonation; D011092:Polyethylene Glycols / Q000494:pharmacology*; D014783:Viscosity; D014827:Vocal Cords / Q000187:drug effects*
chemical_list: D020100:Hydrogels; D011092:Polyethylene Glycols