Effect of Endoscopic Glottoplasty on Acoustic Measures and Quality of Voice: A Systematic Review and Meta-Analysis

  • Mateus Morais Aires
    Address correspondence and reprint requests to Mateus M. Aires, Department of Otolaryngology, Universidade Federal de São Paulo – Rua Botucatu 740, 04023-062 – São Paulo, São Paulo, Brazil.
    Department of Otolaryngology–Head and Neck Surgery of Hospital das Clínicas da Universidade Federal de Pernambuco – Av. Prof. Moraes Rego 1235, Pernambuco, Brazil
    Search for articles by this author
  • Camila Barbosa Marinho
    Department of Otolaryngology–Head and Neck Surgery of Hospital das Clínicas da Universidade Federal de Pernambuco – Av. Prof. Moraes Rego 1235, Pernambuco, Brazil
    Search for articles by this author
  • Camila de Santa Cruz Souza
    Department of Otolaryngology–Head and Neck Surgery of Hospital das Clínicas da Universidade Federal de Pernambuco – Av. Prof. Moraes Rego 1235, Pernambuco, Brazil
    Search for articles by this author
Published:December 01, 2020DOI:



      The voice is an important marker of the transition process to the new gender identity of the transgender person. For 20% of patients seeking voice feminization, voice therapy is not completely satisfactory, and surgery should be considered, with endoscopic glottoplasty being the current practice. While the increase in fundamental frequency (F0) after glottoplasty has been well described, no systematic review of the literature or meta-analysis regarding other acoustic parameters and quality of voice has been performed yet.


      To define the effect of endoscopic glottoplasty on acoustic measures and quality of voice by assessing F0, maximum phonation time (MPT), frequency range, and grade of dysphonia.


      A literature review was performed in Medline/PubMed, Cochrane, Science Direct, LILACS, and Google Scholar, following PRISMA guidelines, with no constraints on publication date. We included studies in English, Portuguese or Spanish that assessed transgender women who underwent endoscopic glottoplasty. All the included articles were measured in terms of their methodological quality.


      The PRISMA approach yielded 14 studies, totaling 566 patients. There was significant heterogeneity between studies regarding follow-up time, surgical technique and perioperative care. Thirteen studies were submitted to meta-analysis. The results showed significant changes in pre- to postglottoplasty mean differences of F0 = 78.49 Hz (95%CI: 75.69–81.30), MPT = −1.11 seconds (95%CI −1.67 to −0.54), frequency range = −3.55 semitones (95%CI −5.74 to −1.36) and grade of dysphonia on the GRBAS scale = 0.44 (95%CI 0.27–0.61).


      Glottoplasty is effective in significantly increasing fundamental frequency, but slightly decreases MPT, frequency range and vocal quality measured by the grade of dysphonia on the GRBAS scale.

      Key Words


      VT (voice therapy), F0 (fundamental frequency), F1 (first formant), F2 (second formant), Hz (Hertz), VF (vocal fold), MPT (maximum phonation time), SD (standard deviation), CI (confidence interval), NOS (Newcastle-Ottawa Quality Assessment Adjusted Scale: Cohort Studies), VHI (Voice Handicap Index), TSEQ (Transgender Self-Evaluation Questionnaire), VAS (visual analog scale), PROM (patient-reported outcome measure), TVQMtF (Transgender Voice Questionnaire for Male-to-Female Transsexuals), NS (not stated or not extractable), IV (inverse variance)
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Voice
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • McNeill E.J.
        • Wilson J.A.
        • Clark S.
        • et al.
        Perception of voice in the transgender client.
        J Voice. 2008; 22: 727-733
        • James S.E.
        • Herman J.L.
        • Rankin S.
        • et al.
        The Report of the 2015 US Transgender Survey.
        National Center for Transgender Equality, Washington, DC2016
        • Yılmaz T.
        • Kuşçu O.
        • Sözen T.
        • et al.
        Anterior glottic web formation for voice feminization: experience of 27 patients.
        J Voice. 2017; 31: 757-762
        • Donald P.J.
        Voice change surgery in the transsexual.
        Head Neck Surg. 1982; 4: 433-437
        • Hardy T.L.D.
        • Boliek C.A
        • Wells K.
        • et al.
        Pretreatment acoustic predictors of gender, femininity, and naturalness ratings in individuals with male-to-female gender identity.
        Am J Speech Language Pathol. 2016; 25: 125-137
        • Moore E.
        • Wisniewski A.
        • Dobs A.
        Endocrine treatment of transsexual people: a review of treatment regimens, outcomes, and adverse effects, J.
        Clin Endocrinol Metab. 2003; 88: 3467-3473
        • Hancock A.B.
        • Krissinger J.
        • Owen K.
        Voice perceptions and quality of life of transgender people.
        J Voice. 2011; 25: 553-558
        • Dacakis G.
        • Oates J.
        • Douglas J.
        Beyond voice: perceptions of gender in male-to-female transsexuals.
        Curr Opin Otolaryngol Head Neck Surg. 2012; 20: 165-170
        • Gelfer M.P.
        • Bennett Q.E.
        Speaking fundamental frequency and vowel formant frequencies: effects on perception of gender.
        J Voice. 2013; 27: 556-566
        • Nolan I.T.
        • Morrison S.D.
        • Arowojolu O.
        • et al.
        The role of voice therapy and phonosurgery in transgender vocal feminization.
        J Craniofac Surg. 2019; 30: 1368-1375
        • Gross M.
        Pitch-raising surgery in male-to-female transsexuals.
        J Voice. 1999; 13: 246-250
        • Kelly V.
        • Hertegård S.
        • Eriksson J.
        • et al.
        Effects of gender-confirming pitch-raising surgery in transgender women a long-term follow-up study of acoustic and patient-reported data.
        J Voice. 2019; 33: 781-791
        • Hillenbrand J.M.
        • Clark M.J.
        The role of f (o) and formant frequencies in distinguishing the voices of men and women.
        Atten Percept Psychophys. 2009; 71: 1150-1166
        • Gelfer M.P.
        • Mikos V.A.
        The relative contributions of speaking fundamental frequency and formant frequencies to gender identification based on isolated vowels.
        J Voice. 2005; 19: 544-554
        • Kim H.T.
        A new conceptual approach for voice feminization: 12 years of experience.
        Laryngoscope. 2017; 12: 1102-1108
        • Geneid A.
        • Rihkanen H.
        • Kinnari T.J.
        Long-term outcome of endoscopic shortening and stiffening of the vocal folds to raise the pitch.
        Eur Arch Otorhinolaryngol. 2015; 272: 3751-3756
      1. Cobeta I., Núñez F., Fernández S., et al. Voz en el cambio de género. Patología de la voz. Ponencia oficial de la Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. Barcelona: Marge Médica Books; 2013:313–323. 1st ed.

        • Wendler J.
        • Doherty E.T.
        • Hollien H.
        Voice classification by means of long-term speech spectra.
        Folia Phoniatr. 1980; 32: 51-60
        • Meister J.
        • Hagen R.
        • Shehata-Dieler W.
        • et al.
        Pitch elevation in male-to-female transgender persons-the Würzburg approach.
        J Voice. 2017; 31 (e7-244.e15): 244
        • Remacle M.
        • Matar N.
        • Morsomme D.
        • et al.
        Glottoplasty for male-to-female transsexualism: voice results.
        J Voice. 2011; 25: 120-123
        • Mastronikolis N.S.
        • Remacle M.
        • Biagini M.
        • et al.
        Wendler glottoplasty: an effective pitch raising surgery in male-to-female transsexuals.
        J Voice. 2013; 27: 516-522
        • Orloff L.A.
        • Mann A.P.
        • Damrose J.F.
        • et al.
        Laser-assisted voice adjustment (LAVA) in transsexuals.
        Laryngoscope. 2006; 116: 655-660
        • Mora E.
        • Carrillo A.
        • Giribet A.
        • et al.
        Translation, cultural adaptation, and preliminary evaluation of the Spanish version of the Transgender Voice Questionnaire for Male-to-Female Transsexuals (TVQ MtF).
        J Voice. 2018; 32 (e1-514.e6): 514
        • Finger L.S.
        • Hoffmann C.F.
        • Cielo C.A.
        Maximum phonation time and body mass index in nondysphonic eutrophic children.
        J Voice. 2019; (18.2): 491-497
        • Van Mersbergen M.
        • Lanza E.
        Modulation of relative fundamental frequency during transient emotional states.
        J Voice. 2019; 33: 894-899
        • Casado J.C.
        • Rodríguez-Parra M.J.
        • Adrián J.A.
        Voice feminization in male-to-female transgendered clients after Wendler's glottoplasty with vs. without voice therapy support.
        Eur Arch Otorhinolaryngol. 2017; 274: 2049-2058
        • Dejonckere P.H.
        • Bradley P.
        • Clemente P.
        • et al.
        A basic protocol for functional assessment of voice pathology, especially for investigating the efficacy of (phonosurgical) treatments and evaluating new assessment techniques: guideline elaborated by the Committee on Phoniatrics of the European Laryngological Society (ELS).
        Eur Arch Otorhinolaryngol. 2001; 258: 77-82
        • Mora E.
        • Cobeta I.
        • Becerra A.
        • et al.
        Comparison of cricothyroid approximation and glottoplasty for surgical voice feminization in male-to-female transsexuals.
        Laryngoscope. 2018; 128: 2101-2109
        • Davies S.
        • Papp V.G.
        • Antoni C.
        Voice and communication change for gender nonconforming individuals: giving voice to the person inside.
        Int J Transgend. 2015; 16: 117-159
        • Moher D.
        • Liberati A.
        • Tetzlaff J.
        • et al.
        Preferred reporting items for systematic reviews and meta-analysis: the PRISMA statement.
        J Clin Epidemiol. 2009; 62: 1006-1012
        • Higgins J.P.
        • Green S.
        Cochrane Handbook for Systematic Reviews of Interventions.
        Cochrane Book Series, 2008 (updated)
        • Oxford Centre for Evidence-Based Medicine Levels of Evidence
        The Oxford 2011 Levels of Evidence.
        2020 (Available at:) (Accessed April 20, 2020)
      2. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses. Ottawa Hospital Research Institute. Available from: (Accessed April 20, 2020)

        • Meister J.
        • Kühn H.
        • Shehata-Dieler W.
        • et al.
        Perceptual analysis of the male-to-female transgender voice after glottoplasty-the telephone test.
        Laryngoscope. 2017; 127: 875-881
        • Ballestas A.J.
        • Ballestas S.A.
        • Cuello R.
        Voice feminization surgery with Wendler glottoplasty technique in Barranquilla, Colombia.
        Acta Otorrinolaringol Cir Cabeza Cuello. 2017; 45: 247-253
        • Anderson J.A.
        Pitch elevation in trangendered patients: Anterior glottic web formation assisted by temporary injection augmentation.
        J Voice. 2014; 28: 816-821
        • Paltura C.
        • Yelken K.
        An examination of vocal tract acoustics following Wendler's Glottoplasty, Folia Phoniatr.
        Logop. 2019; 71: 24-28
        • Maertens K.
        • de Jong F.I.
        The voice handicap index as a tool for assessment of the biopsychosocial impact of voice problems.
        B-ENT. 2007; 3: 61-66
        • Coleman R.O.
        A comparison of the contributions of two voice quality characteristics to the perception of maleness and femaleness in the voice.
        J Speech Hear Res. 1976; 19: 168-180
        • Dacakis G.
        The role of voice therapy in male-to-female transsexuals.
        Curr Opin Otolaryngol Head Neck Surg. 2002; 10: 173-177
        • Wolfe V.I.
        • Ratusnik D.L.
        • Smith F.H.
        • et al.
        Intonation and fundamental frequency in male-to-female transsexuals.
        J Speech Hear Disord. 1990; 55: 43-50
        • Gelfer M.P.
        • Schofield K.J.
        Comparison of acoustic and perceptual measures of voice in male-to- female transsexuals perceived as female versus those perceived as male.
        J Voice. 2000; 14: 22-33
        • Fant G.
        A note on vocal tract size factors and non-uniform F-pattern scalings.
        Speech Transm. Lab Q Prog Status Rep. 1966; 7: 22-30
        • Hardy T.L.D.
        • Rieger J.M.
        • Wells K.
        • et al.
        Acoustic predictors of gender attribution, masculinity–femininity, and vocal naturalness ratings amongst transgender and cisgender speakers.
        J Voice. 2020; (34,2e11-300.e26): 300
        • Salm S.
        • Hower K.
        • Neumann S.
        • et al.
        Validation of the German version of the transsexual voice questionnaire for male-to-female transsexuals.
        J Voice. 2020; 34: 68-77
        • Morsomme D.
        • Revis J.
        • Thomas E.
        Translation, adaptation, and preliminary validation of dacakis and davies' "Transsexual Voice Questionnaire (Male to Female)" in French.
        J Voice. 2019; (33,5e13-807.e24): 807
        • Schwarz K.
        • Fontanari A.M.V.
        • Mueller A.
        • et al.
        Transsexual voice questionnaire for male-to-female Brazilian transsexual people.
        J Voice. 2017; 31 (e15-120.e20): 120