title: Cricothyroid joint anatomy as a predicting factor for success of cricoid-thyroid approximation in transwomen.
abstract: Cricoid-thyroid approximation (CTA) performed to elevate the vocal pitch in transwomen fails in about one-third of the patients. The purpose of this study was to test the feasibility of predicting the likelihood of success of CTA by preoperative determination of the crico-thyroid joint (CTJ) type using three-dimensional (3-D) images derived from high-resolution computer tomography (HRCT).
  
  
  
  Prospective cohort study of 18 transwomen who underwent CTA at our institution.
  
  
  
  All patients had a preoperative and a postoperative HRCT of the larynx, as well as pre- and postoperative measurements of the fundamental vocal pitch (F0 ).
  
  
  
  Three-dimensional images showed type A CTJs in 11 patients and type B or C CTJs in seven patients (see below for the definition of these types). Cricoid-thyroid approximation raised the F0 on average by 76 Hz in patients with type A CTJs and by 45 Hz in patients with type B/C CTJs. Moreover, CTA produced a vocal fold elongation of 17% in larynges with type A joint but only of 3% in larynges with type B/C joints.
  
  
  
  Three-dimensional images allow the differentiation of type A versus type B/C CTJs but not the distinction between type B and type C CTJs. Both vocal pitch elevation and vocal fold elongation following CTA are significantly greater in patients with type A CTJs than in patients with type B/C CTJs. Based on these preliminary results, we recommend identifying the CTJ type on 3-D images and limiting CTA to patients with type A CTJs.
  
  
  
  4. Laryngoscope, 126:1380-1384, 2016.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Division of Phoniatrics, University Hospital Basel, Basel, Switzerland.
authors.forename: Sarina
authors.initials: S
authors.lastname: Tschan
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Division of Phoniatrics, University Hospital Basel, Basel, Switzerland.
authors.forename: Flurin
authors.initials: F
authors.lastname: Honegger
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Division of Phoniatrics, University Hospital Basel, Basel, Switzerland.
authors.forename: Claudio
authors.initials: C
authors.lastname: Storck
mesh_terms: D000328:Adult; D003413:Cricoid Cartilage / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007821:Laryngeal Muscles / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D057829:Gender-Affirming Procedures / Q000379:methods*; D013957:Thyroid Cartilage / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed / Q000379:methods*; D063106:Transgender Persons; D016896:Treatment Outcome; D014827:Vocal Cords / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000601:surgery*; D014833:Voice Quality; D055815:Young Adult
keywords: Crico-thyroid joint; cricoid-thyroid approximation; laryngeal biomechanics; laryngeal framework surgery; transwomen; vocal pitch