title: Computed tomographic assessment of the causal factors of unsuccessful medialization thyroplasty.
abstract: CONCLUSIONS
  The present results demonstrate that a small implant size, undercorrection of the vocal fold, antero-posterior implant malposition, and the use of expanded polytetrafluoroethylene (ePTFE) are the primary factors that cause a poor outcome of medialization thyroplasty (MT).
  
  
  OBJECTIVE
  To assess the postoperative laryngeal condition using computed tomography (CT) in patients with unilateral vocal fold paralysis who underwent MT alone, and to identify the primary causal factors in terms of the surgical procedures that affect the outcomes of MT.
  
  
  METHODS
  Twenty-two patients who underwent MT alone were divided into two groups based on either the maximal phonation time or the perceived vocal breathiness. Two laryngologists assessed the postoperative laryngeal CT images during sustained vowel phonation and judged whether there were abnormalities of the arytenoid cartilage position, window position, implant size, and implant position, as well as the degree of correction of the vocal fold. As implant material, a silicone block, ePTFE, and hydroxyapatite had been inserted in 2, 9, and 11 patients, respectively. Comparisons of the prevalence of abnormalities in the abovementioned factors between the different outcomes and between the types of material used for the implant were performed.
  
  
  RESULTS
  Twelve patients with a poor outcome and 10 with a good outcome showed 36 and 18 abnormal findings identified by either of the two laryngologists, respectively. In the poor outcome group, a smaller implant size and undercorrection of the vocal fold showed both high kappa values and a significantly higher prevalence than those in the good outcome group (p < 0.001 and p < 0.05), respectively. The comparison between material types demonstrated that the sheet-like material (ePTFE) group exhibited a significantly higher prevalence of undercorrection than the block-like material group (p < 0.05).
authors.affiliation: Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine , Suita.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Iwahashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Ogawa
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Hosokawa
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Mochizuki
authors.forename: Hidenori
authors.initials: H
authors.lastname: Inohara
mesh_terms: D000293:Adolescent; D000368:Aged; D000369:Aged, 80 and over; D001672:Biocompatible Materials / Q000627:therapeutic use; D017886:Durapatite / Q000627:therapeutic use; D005260:Female; D006801:Humans; D058753:Laryngoplasty / Q000379:methods / Q000706:statistics & numerical data*; D007830:Larynx / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D011138:Polytetrafluoroethylene / Q000627:therapeutic use; D011446:Prospective Studies; D012828:Silicones / Q000627:therapeutic use; D017211:Treatment Failure; D014826:Vocal Cord Paralysis / Q000601:surgery*
chemical_list: D001672:Biocompatible Materials; D012828:Silicones; D011138:Polytetrafluoroethylene; D017886:Durapatite
keywords: Unilateral vocal fold paralysis; ePTFE; hydroxyapatite; implant materials; outcome; silicone block