The purpose of this study is to measure the short- and long-term voice outcome and outcome predictors of glottoplasty, cricothyroid approximation, thyroplasty, and chondrolaryngoplasty using a prospective non-randomized controlled trial and a multidimensional voice assessment protocol. Secondly, a laryngeal magnetic resonance imaging protocol will be developed to measure pre- and postoperative anatomical factors and compare them with the acoustic changes.

Gender-affirming voice surgery (such as glottoplasty, cricothyroid approximation, thyroplasty and chondrolaryngoplasty), in addition to gender-affirming voice training and hormone therapy, plays an important role in achieving a gender-congruent voice in transgender and gender diverse people. In addition, these interventions are sometimes performed on cisgender men or women who wish to change their voice. However, the impact of these interventions on broad voice characteristics needs to be further investigated.

A thyroid chondroplasty is a procedure in which the cartilage of the larynx is flattened to make the larynx ("Adam's apple") less visible. This procedure is sometimes performed in combination with voice surgery. Although clinically in some cases we observe a temporary lowering of the pitch of the voice during thyroid chondroplasty, little is known in the literature about the impact of this surgery on voice characteristics.

The first purpose is to measure the effect of glottoplasty, cricothyroid approximation, thyroplasty and/or thyroid chondroplasty on a) acoustic voice characteristics (such as the pitch and resonance of the voice), b) perception of femininity/masculinity, c) psychosocial well-being and satisfaction and d) the function of the vocal folds.

Persons undergoing a glottoplasty, cricothyroid approximation, thyroplasty and/or thyroid chondroplasty in the head and neck surgery department are routinely invited to several pre- and postoperative check-up appointments in the head and neck surgery and ear, nose and throat department. These people will be invited to participate in the study in which the data, which are routinely collected preoperatively, 1 week, 1 month, 6 months and 12 months postoperatively during a speech-language pathology (SLP) consultation and a head and neck surgery consultation. These data will be used for scientific research to study the outcome of such surgery on phonation. These pre- and post-operative consultations are clinically standard. During these consultations, a voice assessment and videolaryngostroboscopic examination of the vocal folds are routinely performed.

Recordings and images obtained through these studies can be further processed in the context of this scientific research (such as conducting a listening experiment, analyzing (e.g. using the VALI form) and measuring the video laryngostroboscopy results, etc.).

Secondly, factors (determinants) that influence the effect of previous surgical interventions will be studied within this research.

The third purpose of this study is to develop and validate a laryngeal magnetic resonance imaging (MRI) protocol using a laryngeal surface coil to measure pre- and postoperative anatomical factors (vocal fold length and thickness, thyroarytenoid muscle mass and area) and compare them with the acoustic changes.

PURPOSE 1:

Inclusion criteria for surgery participants:

• Persons who will soon undergo surgery on the vocal folds and/or larynx (including glottoplasty, cricothyroid approximation, thyroplasty and/or thyroid chondroplasty) at UZ Gent
• At least 18 years old
• Sufficient command of the Dutch language for understanding the informed consent letter and completing Dutch questionnaires

Inclusion criteria for volunteers to provide speech samples:

- Cisgender men or women

Inclusion criteria for volunteer listeners for the listening experiment:

• Dutch-speaking
• Self-reported normal hearing

PURPOSE 2: same as above.

PURPOSE 3:

Inclusion criteria for the healthy participants:

• At least 18 years old
• Sufficient command of the Dutch language to complete a Dutch questionnaire

Exclusion criteria for the healthy participants:

- One or more contraindications for an MRI examination. These contraindications are checked using a questionnaire (safety checklist).

Inclusion criteria for the pre- and postoperative MRI participants:

- Random selection of +- 10 participants of purpose 1.

Exclusion criteria for the pre- and postoperative MRI participants:

- One or more contraindications for an MRI examination. These contraindications are checked using a questionnaire (safety checklist).

Persons with both a masculine/feminine/nonbinary gender identity

Assessments will be performed by an ENT specialist and SLP of the research group who is blinded to study evolution and group allocation.