University of Twente Student Theses


The use of three-dimensional surface scans for facial feminization surgery : quantification of the indications and results

Dankers, H.H.G. (2023) The use of three-dimensional surface scans for facial feminization surgery : quantification of the indications and results.

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Abstract:Facial feminization surgery (FFS) comprises a broad range of craniomaxillofacial surgical procedures with the objective to change masculine facial features into feminine features. FFS can play an important role in the transition of transgender women, as typically masculine facial features can make it difficult to be perceived as the correct gender. One of the difficulties with FFS is that the indications and results are very subjective and difficult to quantify. The research presented in this thesis focuses on the use of facial three-dimensional surface scans to analyse the facial morphology of transgender women. This can lead to a better understanding and quantification of the indications and results of FFS. The facial morphology of transgender women is analysed and compared to the facial morphology of cisgender male and female faces. This is done by performing a principal component analysis (PCA) on the coordinates of facial three-dimensional surface scans. This is done for the entire facial shape, as well as for the forehead, nose, chin and zygoma region separately. The effect of different FFS procedures on the facial shape is evaluated by comparing preoperative and postoperative facial 3D surface scans of transgender women. Furthermore, the output of the PCA is used to propose a scoring system that can be used to describe the masculinity or femininity of the shape of the face in one single value. Lastly, an artificial intelligence network is trained to be able to classify facial 3D surface scans as either male or female. The comparison between cisgender male, cisgender female and transgender female faces based on the principal component scores did offer some insight into the facial features that differ between cisgender and transgender faces. However, analysis of the individual principal components was demonstrated to be of limited value in comparing preoperative and postoperative scans of transgender women. Combining the individual principal component scores into one single measure of the masculinity and femininity of the face showed promising results for an objective evaluation of the indications and results of FFS. Additionally, classification of the faces of transgender women using an artificial intelligence model illustrated both the need for FFS, as well as the successful results of FFS in terms of creating a feminine shape of the face. The study presented in this thesis demonstrated different approaches to evaluate the facial shape of transgender women before and after FFS. The possible added value of 3D surface scans and facial shape analysis has been illustrated. However, further improvements of the proposed methods are needed before clinical implementation can be considered.
Item Type:Essay (Master)
Radboudumc, Nijmegen, The Netherlands
Amsterdam UMC (VUmc), Amsterdam, The Netherlands
Faculty:TNW: Science and Technology
Subject:44 medicine
Programme:Technical Medicine MSc (60033)
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