title: Clinical experience with collagen injection of the vocal fold: a study of 155 patients.
abstract: OBJECTIVE
  This study evaluated the results of laryngeal collagen injection.
  
  
  METHODS
  Retrospective study of patients who had undergone laryngeal collagen injection.
  
  
  METHODS
  A retrospective review of 275 patients treated with collagen injection and a review of the relevant literature on the results of treatment were presented. Follow-up studies were performed for at least 3 months on 155 patients. The patients' voice quality was assessed by perceptual voice analysis using the GRBAS scale, and their vocal function was assessed by acoustic and aerodynamic measures (maximal phonation time and mean flow rate). Assessments were performed before and after collagen injection.
  
  
  RESULTS
  Mean objective measures and clinician's perceptual ratings demonstrated measurable improvement in vocal function and voice quality after collagen injection. There were no major complications and no hypersensitivity reactions.
  
  
  CONCLUSIONS
  As an outpatient office procedure, collagen injection offers a simple, efficient and effective treatment for dysphonia. Various aspects of the procedure for anesthesia, injection techniques, and patient selection are discussed.
authors.affiliation: Department of Otorhinolaryngology and Head and Neck Surgery, Graduate School of Medicine and Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. mkimu-tky@umin.ac.jp
authors.forename: Miwako
authors.initials: M
authors.lastname: Kimura
authors.forename: Takaharu
authors.initials: T
authors.lastname: Nito
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Sakakibara
authors.forename: Niro
authors.initials: N
authors.lastname: Tayama
authors.forename: Seiji
authors.initials: S
authors.lastname: Niimi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003094:Collagen / Q000008:administration & dosage*; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007273:Injections, Intramuscular / Q000295:instrumentation*; D020704:Laryngoscopes; D008297:Male; D008875:Middle Aged; D010699:Phonation; D013018:Sound Spectrography; D013061:Speech Acoustics; D049489:Stroboscopy; D014827:Vocal Cords; D014832:Voice Disorders / Q000209:etiology / Q000628:therapy*; D014833:Voice Quality