title: Shape of Thyroid Cartilage Influences Outcome of Montgomery Medialization Thyroplasty: A Gender Issue.
abstract: OBJECTIVE
  This study aimed to determine whether the shape of the thyroid cartilage and gender influence voice outcomes after a Montgomery thyroplasty implant system (MTIS).
  
  
  METHODS
  A retrospective cohort study was performed on 20 consecutive patients who underwent MTIS. Voice outcome variables were the relative decrease in Voice Handicap Index (%) and the absolute increase in maximum phonation time (MPT) (in seconds). Material variables were the angle between the thyroid cartilage laminae (α-angle), the size of the prosthesis, and a combination of both (the α-ratio). Continuous variables were analyzed using medians and were compared between groups using the Mann-Whitney U test. Factors associated with the outcome variables were assessed by multivariable linear regression. A Pearson coefficient was calculated between material variables.
  
  
  RESULTS
  The absolute increase in MPT between the pre- and postoperative period was significantly different between men and women, with a median absolute increase of 11.0 seconds for men and of 1.3 seconds for women (P < 0.001). A strong inverse correlation between the α-ratio and the absolute increase in MPT is observed in all patients, with a Pearson correlation coefficient R = -0.769 (P < 0.001). No factors were significantly associated with the relative Voice Handicap Index decrease in univariable or multivariable analyses. A better Pearson coefficient between the α-angle and the prosthesis size was found for females (0.8 vs 0.71).
  
  
  CONCLUSIONS
  The MTIS is a good thyroplasty modality for male patients, but inadequate design of MTIS female implants leads to poor MPT outcomes. This represents a gender issue that needs to be further studied and eventually tackled.
authors: Otolaryngology Head and Neck Department, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium. Electronic address: gauthier.desuter@uclouvain.be.
authors: Gauthier
authors: G
authors: Desuter
authors: Institute of Health and Society (IRSS), Université catholique de Louvain, Brussels, Belgium.
authors: Sylvie
authors: S
authors: Henrard
authors: Otolaryngology Dpt, Flevoziekenhuis, Almere, The Netherlands.
authors: Julie T
authors: JT
authors: Van Lith-Bijl
authors: Otolaryngology Head and Neck Department, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium.
authors: Avigaëlle
authors: A
authors: Amory
authors: Radiology Department, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium.
authors: Thierry
authors: T
authors: Duprez
authors: Otolaryngology Head and Neck Surgery Department, LUMC, University of Leiden, Leiden, The Netherlands.
authors: Peter Paul
authors: PP
authors: van Benthem
authors: Otolaryngology Head and Neck Surgery Department, LUMC, University of Leiden, Leiden, The Netherlands.
authors: Elisabeth
authors: E
authors: Sjögren
mesh_terms: D000368:Aged; D004185:Disability Evaluation; D055154:Dysphonia / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D058753:Laryngoplasty / Q000009:adverse effects / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D010699:Phonation; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D012189:Retrospective Studies; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013957:Thyroid Cartilage / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014826:Vocal Cord Paralysis / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D014833:Voice Quality
keywords: Gender; Larynx anatomy; Montgomery implant; Thyroplasty; Voice outcome