Wentworth, Adam

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.

AbstractThe success of radial head arthroplasty (RHA) relies on the design of the implant and precision of the surgical technique, with preoperative planning potentially playing a crucial role. The accurate establishment of a patient‐specific anatomical coordinate system (ACS) is essential for this planning process. This study tested the hypothesis that an innovative automated method would be an accurate, reliable, and efficient framework to determine the ACS of the proximal radius, which would be a step toward improving the precision of RHA planning. We used advanced computational techniques to analyze 50 forearm CT scans, comparing the accuracy, reproducibility, reliability, and efficiency of the automated method with manually derived ACS using expert observers as benchmarks. The results showed that the automated approach was more accurate in identifying anatomical landmarks, with smaller mean distance discrepancies (0.6 mm) than manual observers (1 mm). Its reproducibility was also superior, with narrower reproducibility limits, particularly for ulnar notch landmarks (0.6 to 0.8 mm compared to manual selection 1.2 to 1.4 mm) (p = .01). In addition, the limits of agreement and the mean absolute rotational and translational differences of the axes were narrower for the automated method, which also reduced the construction time to an average of 46 s compared to 150 s manually (p < .001). These findings suggest that the automated method has the potential to enhance the accuracy and efficiency of preoperative and postoperative computer‐assisted procedures for RHA. Further research is needed to fully understand the utility of this automated system for enhancing RHA computer‐assisted surgical planning.

Background: Facial shape is significantly influenced by the underlying facial bony skeleton. Sexual dimorphisms in these structures are crucial for craniofacial, aesthetic, and gender-affirming surgery. Previous studies have examined the orbits and upper face, but less is known about the midface. This study aimed to elucidate the sexual dimorphism in the midface region, focusing on the maxilla and zygomatic bones. Methods: A retrospective review was conducted using facial computed tomography scans from 101 White patients aged 20–79 years, using Materialise Mimics and 3-Matics for segmentation and 3D reconstruction. Measurements and statistical shape modeling of the midfacial skeleton were performed. Results: Our results show a distinct sexual dimorphism in the midfacial skeletal structure across all age groups. Women typically had a narrower bizygomatic width by 1.5 mm (P = 0.04), a shallower maxillary depth by 1.6 mm (P < 0.01), and a midfacial vertical height that was 4 mm shorter than that of men (P = 0.018). In contrast, men exhibited a greater distance between the frontozygomatic sutures by 5.4 mm (P < 0.01), a 3-mm greater interorbitale distance (P < 0.01), and a 2.1-mm wider infraorbital foramina distance (P = 0.007). There were no significant differences in the pyriform and maxillary angles (P = 0.15 and P = 0.52, respectively). Conclusions: Our analysis of midfacial skeletal anatomy revealed sexual dimorphism differences. Men exhibited more pronounced facial features than women, with a broader horizontal midfacial skeleton, a longer midfacial vertical height, and greater maxillary depths compared with women.

Background: With neck, aging the cervicomental angle becomes obtuse and may be influenced by hyoid bone aging. An understanding of hyoid position changes with aging will further our understanding of its role in neck contour changes. Methods: A 3D volumetric reconstruction of 282 neck computed tomography scans was performed. The cohort was categorized into three groups based on age: 20 years or older and younger than 40 years, 40 years or older and younger than 60 years, and 60 years or older and younger than 80 years. The vertical and horizontal hyoid distances in relation to the mandible were calculated for each patient. Results: A total of 282 patients (153 women, 129 men) were included in the cohort. The age groups were evenly distributed in men and women. Mean hyoid vertical and horizontal distances differed between women and men in all age groups. There was a significant difference in the hyoid vertical distance between 20–39 years old to 40–59 years old in men (P < 0.01), and 20–39 years old to 60–79 years old in both genders (women P = 0.005, men P < 0.01). Hyoid horizontal distance was not affected by age and sex (age and sex: P > 0.05), but rather by body mass index (BMI). Every 5 BMI points corresponded to a forward movement of 2 mm. Conclusions: As individuals age, the hyoid bone descends in both sexes, and an increase in BMI is associated with forward movement. Additional studies are needed to assess the correlation of the hyoid position between upright and supine positions.

Case: This report describes the case of an athletic 12-year-old boy who presented with a 64° left proximal humeral varus angulation deformity and physeal bar secondary to multiple operations for a proximal humeral metaphyseal cystic lesion and pathologic fracture. Using a combined lateral closing and medial opening-wedge osteotomy, a 68° valgus correction was achieved with excellent clinical and functional outcomes at 16-month follow-up. Forward flexion increased from 120 to 170° preoperatively to postoperatively while abduction improved from 110° preoperatively to 170° postoperatively. Conclusion: A combined lateral closing and medial opening-wedge osteotomy of the proximal humerus can successfully treat cases of extreme proximal humerus varus in the growing shoulder where unilateral or dome osteotomies are not suitable.

Abstract Trochlear dysplasia is a major contributor to patellofemoral instability and subsequent failure of isolated soft tissue reconstruction procedures in the treatment of recurrent patellar dislocation and/or subluxation. Trochleoplasty procedures aim to address abnormal osseous trochlear morphologic factors that contribute to patellar maltracking. However, teaching these techniques is limited by the lack of reliable training models for trochlear dysplasia and trochleoplasty simulation. Although a cadaveric knee model of trochlear dysplasia for trochleoplasty simulation has been recently described, cadaveric knees are less amenable for use in trochleoplasty planning and surgeon training because of the absence of reliable, natural dysplastic anatomic relationships, such as suprapatellar spurs due to the rarity of dysplastic cadavers and the high cost of cadaveric specimens. Furthermore, readily available sawbone models represent “normal” osseous trochlear morphology and are difficult to modify and bend due to their material composition. Given this, we have developed a cost‐effective, reliable, and anatomically accurate three‐dimensional (3D) knee model of trochlear dysplasia for trochleoplasty simulation and trainee education. Technique Video video See video under supplementary data.

AbstractPurpose: Evaluation of an adjustable chin rest apparatus for visual field machine.Methods: The HFA 60‐4 visual field test was performed in the primary position and then repeated in the optimum head turn angle using an adjustable chin rest to maximize a visual field for each subject. The optimum head turn angle was calculated using a 3D face model. A 3D model of the face of the subjects was reconstructed using a single facial photo and a Convolutional Neural Networks (CNN), which is a deep learning algorithm. The angles between visual axis and all points around it on the face surface were calculated and the points on the 3D face model with the angle less than 60 degrees was used to predict the optimal head turn angle. A chin rest apparatus for a visual field system was made by 3D printing. The chin rest apparatus includes a moveable chin rest insert coupled to the base and configured to be adjusted to one of a plurality of head turn angles.Results: Three eyes from three healthy subjects (2 female and 1 male) with the mean age of 27.33, CI: 7.37 were enrolled. The visual field defects cause by the facial contour of the subject was decreased by turning the subject's head relative to a vertical axis away from (nasally) the eye being tested using a visual field system with the adaptive chin rest. The mean threshold of the visual field tests of all eyes in the primary angle and optimized angle was 1496, CI: 380.22 and 1567.67, CI: 295.37 respectively. Mean of the degree of head turn to maximize the visual field for all individuals was 6.67 degrees, CI: 2.88.Conclusions: The described adaptive chin rest can be used to position a subject's head at an optimal head turn angle that minimizes the visual field defects caused by the facial contours and maximizes the measured visual field of the subject. This technology can be used in far peripheral visual field tests for early detection of glaucoma as well as accurate follow up of disease progression.