title: Viscoelastic properties of phonosurgical biomaterials at phonatory frequencies.
abstract: OBJECTIVE
  The purpose of this study was to examine the functional biomechanical properties of several injectable biomaterials currently or potentially used for vocal fold augmentation.
  
  
  METHODS
  Rheometric investigation of phonosurgical materials in vitro.
  
  
  METHODS
  Linear viscoelastic shear properties of 3% bovine collagen (atelocollagen), micronized AlloDerm (Cymetra; LifeCell Corp., Branchburg, NJ), calcium hydroxylapatite (CaHA) (Radiesse; BioForm Medical, San Mateo, CA), and 2.4% cross-linked hyaluronic acid (HA) gel (Juvéderm; Allergan, Inc., Irvine, CA) were quantified as functions of frequency covering the phonatory range, and compared to those of the human vocal fold cover. Measurements of elastic shear modulus (G') and dynamic viscosity (eta') were made at up to 250 Hz with a controlled-strain simple-shear rheometer. Linear least-squares regression was conducted to curve-fit log G' and log eta' versus log frequency, and statistical analysis was performed with one-way analysis of variance.
  
  
  RESULTS
  Radiesse and Cymetra were found to be the stiffest and the most viscous materials, followed by Juvéderm and atelocollagen. There were significant differences in the magnitudes of G' and eta' among the phonosurgical materials and the normal human vocal fold cover (p < .001), whereas there was no significant difference in the frequency dependence of G' and eta' among the materials. Post hoc Tukey tests revealed significant differences (p < .05) in pairwise comparisons of the magnitudes of G' and eta' among all materials and the vocal fold cover.
  
  
  CONCLUSIONS
  These findings suggested that although these biomaterials may be injected lateral to the lamina propria for the treatment of glottic insufficiency, none of them are rheologically optimal for the functional reconstruction of the vocal fold lamina propria.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9035, USA.
authors.forename: Miwako
authors.initials: M
authors.lastname: Kimura
authors.forename: Ted
authors.initials: T
authors.lastname: Mau
authors.forename: Roger W
authors.initials: RW
authors.lastname: Chan
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000032:analysis*; D001696:Biomechanical Phenomena; D002417:Cattle; D003094:Collagen / Q000008:administration & dosage / Q000032:analysis*; D004548:Elasticity; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000032:analysis; D007267:Injections; D007820:Laryngeal Mucosa / Q000502:physiology; D010699:Phonation / Q000502:physiology*; D012212:Rheology; D014783:Viscosity; D014826:Vocal Cord Paralysis / Q000601:surgery; D014827:Vocal Cords / Q000502:physiology*
chemical_list: D001672:Biocompatible Materials; C471832:Cymetra; C526061:Juvederm Ultra; C059821:atelocollagen; D006820:Hyaluronic Acid; D003094:Collagen