title: Collagen injection as a supplement to arytenoid adduction for vocal fold paralysis.
abstract: OBJECTIVE
  Dysphonia associated with vocal fold paralysis can persist even after successful medialization procedures, including arytenoid adduction. It is hypothesized that laryngeal collagen injection could improve phonation following arytenoid adduction in selected patients. Our objective was to evaluate how collagen injection could result in measurable improvements in vocal function and voice quality.
  
  
  METHODS
  Forty patients with unilateral vocal fold paralysis who had undergone arytenoid adduction underwent transoral injection of non-cross-linked bovine dermal collagen by means of indirect laryngoscopy and a curved injection device. A control group of 40 patients underwent arytenoid adduction but not collagen injection. The patients' voice quality was assessed perceptually with the GRBAS scale, and vocal function was assessed by acoustic and aerodynamic measures (maximum phonation time and transglottal DC flow). The relative glottal area was also assessed by videostroboscopy.
  
  
  RESULTS
  Significant improvements in vocal function and voice quality were observed with collagen injection for those patients who did not achieve satisfactory glottal competence with arytenoid adduction alone. Glottal area measurements revealed that glottic insufficiency was significantly reduced after arytenoid adduction as well as after collagen injection.
  
  
  CONCLUSIONS
  The findings suggest that collagen injection could be an effective supplementary treatment for improving voice following arytenoid adduction. It has the advantage of being a minimally invasive outpatient office procedure. The long-term efficacy of the procedure should be explored.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School of Medicine, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Miwako
authors.initials: M
authors.lastname: Kimura
authors.forename: Takaharu
authors.initials: T
authors.lastname: Nito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imagawa
authors.forename: Niro
authors.initials: N
authors.lastname: Tayama
authors.forename: Roger W
authors.initials: RW
authors.lastname: Chan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001193:Arytenoid Cartilage / Q000601:surgery*; D003094:Collagen / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014826:Vocal Cord Paralysis / Q000628:therapy*
chemical_list: D003094:Collagen