title: Long-term acoustic comparison of thyroplasty versus autologous fat injection.
abstract: OBJECTIVE
  Medialization by thyroplasty or intracordal autologous fat injection provides voice improvement in patients with unilateral vocal fold paralysis. Thyroplasty is considered a "permanent" medialization, whereas fat injection is considered "temporary" because of reabsorption. The objective of this study was to compare the evolution of acoustic parameters for these procedures over 1 year and to evaluate the results of fat injection at 2 years.
  
  
  METHODS
  From 1994 to 1998, 46 consecutive patients (17 women and 29 men) were treated exclusively by intracordal injection of autologous fat, and then from 1999 to 2002, 48 consecutive patients (19 women and 29 men) were treated with the Montgomery Thyroplasty Implant System or Gore-Tex thyroplasty. Each patient's voice was prospectively recorded before operation and at 1,3, 12, and 24 months after operation. Six patients (13%) in the injection group underwent a second injection, and 1 patient (2%) in the thyroplasty group underwent revision surgery. Jitter, shimmer, and noise-to-harmonics ratio (NHR) were calculated for a 1000-ms midvowel segment of the vowel /a/.
  
  
  RESULTS
  One month after operation, jitter, shimmer, and NHR were significantly improved in both groups (Wilcoxon's test, p < 0.05 in all cases). Jitter and shimmer did not change significantly between 1 and 3 months or between 1 and 12 months (p > 0.05). The NHR had improved at 12 months in both groups (injection, p = 0.0004; thyroplasty, p = 0.0178) and at 24 months in the injection group (p = 0.0076). No significant difference was noted between the two techniques before operation or at 1, 3, or 12 months after operation (Mann-Whitney test, p > 0.05). Jitter and shimmer had not changed significantly after 24 months in either group. At 24 months, there was no difference in acoustic parameters between the two treatment groups.
  
  
  CONCLUSIONS
  The two techniques provided comparable objective acoustic voice improvement. At 2 years, autologous fat injection provides long-term acoustic voice improvement comparable to that of thyroplasty, but it has a higher rate of revision surgery.
authors.affiliation: Phonetics and Phonology Laboratory, CNRS UMR 7018/Sorbonne Nouvelle.
authors.forename: Dana M
authors.initials: DM
authors.lastname: Hartl
authors.forename: Stephane
authors.initials: S
authors.lastname: Hans
authors.forename: Lise
authors.initials: L
authors.lastname: Crevier-Buchman
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Vaissière
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Brasnu
mesh_terms: D050153:Abdominal Fat / Q000637:transplantation*; D000328:Adult; D000368:Aged; D001672:Biocompatible Materials / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011138:Polytetrafluoroethylene / Q000627:therapeutic use; D019736:Prostheses and Implants; D012189:Retrospective Studies; D013061:Speech Acoustics; D013957:Thyroid Cartilage / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D014826:Vocal Cord Paralysis / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D014832:Voice Disorders / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D014833:Voice Quality
chemical_list: D001672:Biocompatible Materials; D011138:Polytetrafluoroethylene