Pazelli, Alexandre M.

Fibrous dysplasia (FD) is a benign bone neoplasm often considered a disease of childhood, with existing literature suggesting lesions typically become quiescent by young adulthood. Consequently, the presentations and surgical outcomes of adult patients remain poorly characterized. This retrospective review analyzed 50 adult patients treated surgically for craniofacial FD at a single institution between 1988 and 2024 to evaluate patterns of presentation, operative indications, and long-term outcomes. The cohort (54.0% male) had a mean follow-up of 15.8 years. Polyostotic involvement was present in 60.0% of patients, and the frontal bone was most affected (51.2%). The median age at presentation was 31 years, and the median age at initial surgery was 34.5 years. The most common surgical indications were visible growth (30.5%) and pain or headache (27.1%). Of the 59 surgeries performed to directly treat FD, bone contouring only was the most common initial operative approach (n=42), followed by en bloc resection and reconstruction (n=7). However, 12% of patients undergoing initial contouring required additional operations for continued growth. All secondary deformities requiring corrective surgery were ocular. In addition, several patients demonstrated delayed recurrence or progression decades after primary surgical intervention. These findings suggest that craniofacial FD may remain symptomatic or continue to progress into adulthood, challenging the traditional paradigm that these lesions necessarily become quiescent after skeletal maturity and highlighting the importance of long-term surveillance in the adult population.

Background: Sexual dimorphism in the facial skeleton is fundamental to aesthetics and gender perception. This study employs AI-assisted three-dimensional (3D) imaging to analyze morphological differences between males and females in the upper, mid, and lower facial regions. Methods: A retrospective analysis was conducted on 280 high-resolution craniofacial CT scans (147 females, 133 males) of adults aged 20 years and older. AI-assisted segmentation and modeling were performed using Materialise Mimics and 3-Matic software. The facial skeleton was divided into upper, mid, and lower regions for detailed morphometric evaluation. Statistical shape modeling (SSM) and heatmaps were used to visualize surface projection differences across age groups. Statistical comparisons were conducted to assess gender-based variation. Results: Significant sexual dimorphism was observed across all facial regions. In the upper face, males had greater interorbital width, frontotemporal brow width, inter-medial canthi distance, and more prominent frontal bossing. In the midface, males exhibited increased width, depth, and vertical height, with the most pronounced differences occurring in middle age. The lower face showed larger mandibular dimensions in males, including bigonial width, ramus height, and a sharper mental angle, while females had a more rounded chin and smoother mandibular contour. Heatmaps confirmed greater surface projection in male skeletons, particularly in the gonial and midfacial regions, with dimorphism decreasing with age. Conclusion: This represents the first large-sample CT study utilizing AI to comprehensively quantify facial skeletal dimorphism. Findings support the importance of gender-specific planning in facial reconstructive and aesthetic procedures.

Background: Mandible contour significantly influences facial appearance, framing the lower facial silhouette. Redefining mandibular contour is key for facial and neck rejuvenation. Yet, there is limited facial aging research across different lifespans and sexes. Here, we utilize artificial intelligence and advanced 3-dimensional (3D) analysis to elucidate mandibular aging patterns in male and female subjects. Methods: A retrospective analysis of facial computed tomography scans in White patients was conducted, categorizing subjects into 3 age groups (20–79 y) and stratifying them by sex. Artificial intelligence–assisted segmentation into 3D mandibles was done in Mimics v.25, and statistical shape modeling was used to create an average mandible for each group. Volume and linear measurements were assessed via 3D overlays. Results: Analysis of 280 mandibles demonstrated statistically significant aging changes in both sexes. Ramus height showed a marked decrease with age, by approximately 5.3 mm in women and 4.2 mm in men (P < 0.001). Interrami and intercondylar widths increased by a mean of 4–5 mm (P < 0.01). Women exhibited an increase in mandibular angle (P < 0.01), and bony resorption over the chin compared to men, who exhibited concentrated bone resorption at the gonion projection. Conclusions: Mandibular aging, independent of tooth loss, exhibits specific bone remodeling patterns by sex. Posteriorly, mandibular widths increase in both sexes, whereas ramus height decreases. Women experience more resorption at the anterior alveolar surface and chin than men. Statistical shape modeling effectively visualizes these patterns on a population level, bridging the gap between traditional aging research and current understanding.