Date of Award

January 2026

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Michael Alperovich

Abstract

Facial feminization surgery (FFS) reshapes bony and soft tissue to makemasculine facial features more recognizably feminine, as hormone therapy alone has some but nevertheless limited impact. FFS improves both patient and external perceptions of patient femininity, playing an essential role in relieving gender dysphoria in transgender individuals. The forehead, chin, and mandible are critical for gender identification, making them key targets for surgical intervention and morphometric evaluation. Thus far, cephalometric assessments of postoperative changes in FFS have been limited by small sample size and to one region of the face. Therefore, this study aimed to quantitatively characterize skeletal morphometric changes of the forehead, chin, and mandible in a large cohort of patients undergoing FFS at an academic medical center. Using three-dimensional CT segmentation, our data characterize the magnitude and direction of osseous change following contemporary surgical techniques. Additionally, this work sought to examine whether the magnitude of postoperative modification was associated with baseline preoperative anatomy and to determine the degree to which postoperative morphology approximated assigned-female-at-birth (AFAB) reference subjects using normalized similarity metrics. This retrospective study included patients who underwent facial feminization surgery between 2020 and 2024 at a single academic medical center and had both preoperative and postoperative craniofacial CT imaging available for analysis. Mimics software (Materialise, Leuven, Belgium) was used to segment bony regions of interest for the forehead, chin, and gonial angle, and alignment planes were applied consistently across scans to minimize positional variability. Volume and surface area were calculated for the three regions of interest; additional measurements included frontonasal and bossing angles for the forehead, sagittal and vertical projections for the chin, and intergonial-interzygomatic distance ratio for the gonial angles. Five AFAB individuals were randomly selected from the New Mexico Decedent Imaging Database to serve as a reference cohort. Preoperative and postoperative measurements were compared using one-tailed paired t-tests, and associations between magnitude of postoperative change and corresponding preoperative measurements were assessed using Pearson correlation coefficients and univariate linear regression. A total of 80 patients met inclusion criteria. Significant reductions were observed in forehead volume, surface area, frontonasal angle, and bossing angle (p < 0.05). Additionally, chin volume decreased significantly (p = 0.003) and sagittal projection increased significantly (p < 0.001). Gonial angle volume, surface area, and intergonial- interzygomatic distance ratio also decreased significantly (p < 0.001). Similarity analysis demonstrated substantial approximation toward AFAB reference morphometrics across regions, with particularly high similarity in angular and proportional measures.

Comments

This thesis is restricted to Yale network users only. This thesis is permanently embargoed from public release.

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