Picture perfect? Reliability of craniofacial anthropometry using three-dimensional digital stereophotogrammetry

Photogrammetry is a useful tool to assess the aesthetic outcome after excision and reconstruction of the nose skin tumors

BACKGROUNDOBJECTIVE

Post-oncological nasal reconstruction presents both aesthetic and functional challenges. While established methods exist for quantitatively evaluating functional results following surgery, equivalent systems for assessing aesthetic outcomes are lacking. Three-dimensional (3D) photogrammetry, already used in maxillofacial and orthodontic surgery for aesthetic evaluation, overcomes some limitations of traditional methods like direct anthropometry. However, its applicability in oncological facial reconstruction has not yet been explored. In our study, we applied the 3dMDtrio™ system for the quantitative analysis of line and surface modifications following nasal reconstruction.

METHODS

We conducted a prospective observational study enrolling patients with skin neoplasms located on the nose undergoing surgical excision and reconstruction. Using the 3dMDtrio™ system, we measured the dimensions and projections of nasal surfaces and the positions of specific landmarks before and after surgery. The surface measurements were then correlated with aesthetic evaluations performed by three plastic surgeons, not involved in the procedure, using a 5-point Likert scale.

RESULTS

We included 33 patients with a mean age of 71 years, ranging from 40 to 94. We obtained complete documentation of all postoperative measurements for 21 patients. We observed significant changes in the positions of the landmarks post-surgery, limited to the right ala and nasion. The average nasal surface area was 4674.41 mm2 ± 477.24 mm2 before surgery and 4667.95 mm2 ± 474.12 mm2 after surgery, with no significant discrepancies. The evaluation using the Likert scale revealed an average score of 3.04 ± 0.48, with a significant negative correlation to the measured surface changes.

CONCLUSION

Our findings suggest that 3D photogrammetry can be considered a valid method for objectively assessing volumetric changes associated with post-oncological nasal reconstructive surgery.

Volumetric Analyses of Dysmorphic Maxillofacial Structures Using 3D Surface-Based Approaches: A Scoping Review

Background/Objectives: Three-dimensional (3D) analysis of maxillofacial structures in dysmorphic patients offers clinical advantages over 2D analysis due to its high accuracy and precision in measuring many morphological parameters. Currently, no reliable gold standard exists for calculating 3D volumetric measurements of maxillofacial structures when captured by 3D surface imaging techniques. The aim of this scoping review is to provide an overview of the scientific literature related to 3D surface imaging methods used for volumetric analysis of the dysmorphic maxillofacial structures of patients affected by CL/P or other syndromes and to provide an update on the existing protocols, methods, and, when available, reference data. Methods: A total of 17 papers selected according to strict inclusion and exclusion criteria were reviewed for the qualitative analysis out of more than 4500 articles published between 2002 and 2024 that were retrieved from the main electronic scientific databases according to the PRISMA-ScR guidelines. A qualitative synthesis of the protocols used for the selection of the anatomical areas of interest and details on the methods used for the calculation of their volume was completed. Results: The results suggest a great degree of heterogeneity between the reviewed studies in all the aspects analysed (patient population, anatomical structure, area selection, and volume calculation), which prevents any chance of direct comparison between the reported volumetric data. Conclusions: Our qualitative analysis revealed dissimilarities in the procedures specified in the studies, highlighting the need to develop uniform methods and protocols and the need for comparative studies to verify the validity of methods in order to achieve high levels of scientific evidence, homogeneity of volumetric data, and clinical consensus on the methods to use for 3D volumetric surface-based analysis.

Creation of the Scaphocephalic Index: Measurement of Global and Regional Severity in Scaphocephaly

BACKGROUND

The recently described frontal bossing index (FBI) and occipital bullet index (OBI) allow for quantification of scaphocephaly. A similar index examining biparietal narrowing has not been described. Addition of such an index measuring width would allow for direct evaluation of the primary growth restriction in sagittal craniosynostosis and the formation of an optimized global width/length measure.

METHODS

Computed tomography scans and three-dimensional photographs were used to recreate scalp surface anatomy. Equidistant axial, sagittal, and coronal planes were overlaid, creating a Cartesian grid. Points of intersection were analyzed for population trends in biparietal width. Using the most descriptive point coupled with the sellion protrusion to control for head size, the vertex narrowing index is formed. By combining this index with the FBI and OBI, the scaphocephalic index (SCI) is created as a tailored width/length measure.

RESULTS

Using 221 controls and 360 individuals with sagittal craniosynostosis, the greatest difference occurred superiorly and posteriorly at a point 70% of the head's height and 60% of the head's length. This point had an area under the curve of 0.97 and sensitivity and specificity of 91.2% and 92.2%, respectively. The SCI has an area under the curve of 0.9997, sensitivity and specificity greater than 99%, and interrater reliability of 0.995. The correlation coefficient between computed tomography imaging and three-dimensional photography was 0.96.

CONCLUSIONS

The vertex narrowing index, FBI, and OBI evaluate regional severity, while the SCI is able to describe global morphology in patients with sagittal craniosynostosis. These measures allow for superior diagnosis, surgical planning, and outcome assessment, independent of radiation.

Automatic three-dimensional facial symmetry reference plane construction based on facial planar reflective symmetry net

OBJECTIVES

Three-dimensional (3D) facial symmetry analysis is based on the 3D symmetry reference plane (SRP). Artificial intelligence (AI) is widely used in the dental and oral sciences. This study developed a novel deep learning model called the facial planar reflective symmetry net (FPRS-Net) to automatically construct an SRP and established a method for defining a 3D point-cloud region of interest (ROI) and high-dimensional feature computations suitable for this network model.

METHODS

Overall, 240 patients were enroled. The deep learning model was trained and predicted using 200 samples, and its clinical suitability was evaluated with 40 samples. Four FPRS-Net models were prepared, each using supervised and unsupervised learning approaches based on full facial and ROI data (FPRS-NetS, FPRS-NetSR, FPRS-NetU, and FPRS-NetUR). These models were trained on 160 3D facial datasets, validated on 20 cases, and tested on another 20 cases. The model predictions were evaluated using an additional 40 clinical 3D facial datasets by comparing the mean square error of the SRP between the parameters predicted by the four FPRS-Net models and the truth plane. The clinical suitability of FPRS-Net models was evaluated by measuring the angle error between the predicted and ground-truth planes; experts evaluated the predicted SRP of the four FPRS-Net models using the visual analogue scales (VAS) method.

RESULTS

The FPRS-NetSR and FPRS-NetU models achieved an average angle error of 0.84° and 0.99° in predicting 3D facial SRP, respectively, with a VAS value of >8. Using the four FPRS-Net models to create an SRP in 40 cases of 3D facial data required <4 s.

CONCLUSIONS

Our study demonstrated a new solution for automatically constructing oral clinical 3D facial SRPs.

CLINICAL SIGNIFICANCE

This study proposes a novel deep learning algorithm (FPRS-Net) to construct a symmetry reference plane that can reduce workload, shorten the time required for digital design, reduce dependence on expert experience, and improve therapeutic efficiency and effectiveness in dental clinics.

"Utility of Smartphone-based Three-dimensional Surface Imaging for Digital Facial Anthropometry"

Background

The utilization of three-dimensional (3D) surface imaging for facial anthropometry is a significant asset for patients undergoing maxillofacial surgery. Notably, there have been recent advancements in smartphone technology that enable 3D surface imaging.In this study, anthropometric assessments of the face were performed using a smartphone and a sophisticated 3D surface imaging system.

Methods

30 healthy volunteers (15 females and 15 males) were included in the study. An iPhone 14 Pro (Apple Inc., USA) using the application 3D Scanner App (Laan Consulting Corp., USA) and the Vectra M5 (Canfield Scientific, USA) were employed to create 3D surface models. For each participant, 19 anthropometric measurements were conducted on the 3D surface models. Subsequently, the anthropometric measurements generated by the two approaches were compared. The statistical techniques employed included the paired t-test, paired Wilcoxon signed-rank test, Bland-Altman analysis, and calculation of the intraclass correlation coefficient (ICC).

Results

All measurements showed excellent agreement between smartphone-based and Vectra M5-based measurements (ICC between 0.85 and 0.97). Statistical analysis revealed no statistically significant differences in the central tendencies for 17 of the 19 linear measurements. Despite the excellent agreement found, Bland-Altman analysis revealed that the 95% limits of agreement between the two methods exceeded ±3 mm for the majority of measurements.

Conclusion

Digital facial anthropometry using smartphones can serve as a valuable supplementary tool for surgeons, enhancing their communication with patients. However, the proposed data suggest that digital facial anthropometry using smartphones may not yet be suitable for certain diagnostic purposes that require high accuracy.

Facial asymmetry and midsagittal plane definition in 3D: A bias-free, automated method

Symmetry is a fundamental biological concept in all living organisms. It is related to a variety of physical and social traits ranging from genetic background integrity and developmental stability to the perception of physical appearance. Within this context, the study of human facial asymmetry carries a unique significance. Here, we validated an efficient method to assess 3D facial surface symmetry by best-fit approximating the original surface to its mirrored one. Following this step, the midsagittal plane of the face was automatically defined at the midpoints of the contralateral corresponding vertices of the superimposed models and colour coded distance maps were constructed. The method was tested by two operators using facial models of different surface size. The results show that the midsagittal plane definition was highly reproducible (maximum error < 0.1 mm or°) and remained robust for different extents of the facial surface model. The symmetry assessments were valid (differences between corresponding bilateral measurement areas < 0.1 mm), highly reproducible (error < 0.01 mm), and were modified by the extent of the initial surface model. The present landmark-free, automated method to assess facial asymmetry and define the midsagittal plane of the face is accurate, objective, easily applicable, comprehensible and cost effective.

Three-Dimensional Anthropometry for Evaluating Philtrum Contour in Patients With Unilateral Cleft Lip: Comparison Between Photographic Assessment and 3-Dimensional Anthropometry

Philtrum reconstruction in patients with unilateral cleft lip is a major concern in cheiloplasty. Moreover, a quantitative evaluation of the philtrum contour has not been possible. Advances in 3-dimensional (3D) imaging technology have enabled highly accurate assessments of facial surfaces. This study aimed to justify using 3D anthropometric measurements to quantify traditional photographic grading systems. Sixty-six children with unilateral cleft lip, aged 4 to 6 years (mean age: 69.1±5.7 mo), who visited the outpatient clinic from January to December 2020 were included. A plastic surgeon panel graded the philtrum contour using digital photographs, and 3D anthropometry was performed using a 3D imaging system. The philtrum height, philtrum height difference, and dimple depth were measured at the middle of the philtrum. The philtrum height did not show significant changes across the photographic scores ( P =0.06), whereas noticeable differences were observed in the dimple depths based on photographic scores ( P <0.001). The correlation analysis revealed the highest correlation between the photographic score and dimple depth (rho=0.897, P <0.001). The philtrum height on the cleft side (rho=0.478, P <0.001) also correlated with the photographic score, but the correlation was weaker than that of the dimple depth. The dimple depth and philtrum height can help define the philtrum contour. Furthermore, the dimple depth reflects the philtrum contour better and is more suitable as a single parameter. However, relying on a single philtrum height measurement may be insufficient for reliable evaluations, as the relative height from the surrounding tissues is more important than the absolute height measured using 3D anthropometry.

Reliability and Agreement of Automated Head Measurements From 3-Dimensional Photogrammetry in Young Children

This study aimed to assess the reliability and agreement of automated head measurements using 3-dimensional (3D) photogrammetry in young children. Specifically, the study evaluated the agreement between manual and automated occipitofrontal circumference (OFC) measurements (n = 264) obtained from 3D images of 188 patients diagnosed with sagittal synostosis using a novel automated method proposed in this study. In addition, the study aimed to determine the interrater and intrarater reliability of the automatically extracted OFC, cephalic index, and volume. The results of the study showed that the automated OFC measurements had an excellent agreement with manual measurements, with a very strong regression score ( R2 = 0.969) and a small mean difference of -0.1 cm (-0.2%). The limits of agreement ranged from -0.93 to 0.74 cm, falling within the reported limits of agreement for manual OFC measurements. High interrater and intrarater reliability of OFC, cephalic index, and volume measurements were also demonstrated. The proposed method for automated OFC measurements was found to be a reliable alternative to manual measurements, which may be particularly beneficial in young children who undergo 3D imaging in craniofacial centers as part of their treatment protocol and in research settings that require a reproducible and transparent pipeline for anthropometric measurements. The method has been incorporated into CraniumPy, an open-source tool for 3D image visualization, registration, and optimization, which is publicly available on GitHub ( https://github.com/T-AbdelAlim/CraniumPy ).

An Open-Source Photogrammetry Workflow for Reconstructing 3D Models

Acquiring accurate 3D biological models efficiently and economically is important for morphological data collection and analysis in organismal biology. In recent years, structure-from-motion (SFM) photogrammetry has become increasingly popular in biological research due to its flexibility and being relatively low cost. SFM photogrammetry registers 2D images for reconstructing camera positions as the basis for 3D modeling and texturing. However, most studies of organismal biology still relied on commercial software to reconstruct the 3D model from photographs, which impeded the adoption of this workflow in our field due the blocking issues such as cost and affordability. Also, prior investigations in photogrammetry did not sufficiently assess the geometric accuracy of the models reconstructed. Consequently, this study has two goals. First, we presented an affordable and highly flexible SFM photogrammetry pipeline based on the open-source package OpenDroneMap (ODM) and its user interface WebODM. Second, we assessed the geometric accuracy of the photogrammetric models acquired from the ODM pipeline by comparing them to the models acquired via microCT scanning, the de facto method to image skeleton. Our sample comprised 15 Aplodontia rufa (mountain beaver) skulls. Using models derived from microCT scans of the samples as reference, our results showed that the geometry of the models derived from ODM was sufficiently accurate for gross metric and morphometric analysis as the measurement errors are usually around or below 2%, and morphometric analysis captured consistent patterns of shape variations in both modalities. However, subtle but distinct differences between the photogrammetric and microCT-derived 3D models could affect the landmark placement, which in return affected the downstream shape analysis, especially when the variance within a sample is relatively small. At the minimum, we strongly advise not combining 3D models derived from these two modalities for geometric morphometric analysis. Our findings can be indictive of similar issues in other SFM photogrammetry tools since the underlying pipelines are similar. We recommend that users run a pilot test of geometric accuracy before using photogrammetric models for morphometric analysis. For the research community, we provide detailed guidance on using our pipeline for building 3D models from photographs.

Validation of three-dimensional facial imaging captured with smartphone-based photogrammetry application in comparison to stereophotogrammetry system

Statement of problem

The development of facial scanners has improved capabilities to create three-dimensional (3D) virtual patients for accurate facial and smile analysis. However, most of these scanners are expensive, stationary and involve a significant clinical footprint. The use of the Apple iPhone and its integrated "TrueDepth" near-infrared (NIR) scanner combined with an image processing application (app) offers the potential to capture and analyze the unique 3D nature of the face; the accuracy and reliability of which are yet to be established for use in clinical dentistry.

Purpose

This study was designed to validate both the trueness and precision of the iPhone 11 Pro smartphone TrueDepth NIR scanner in conjunction with the Bellus3D Face app in capturing 3D facial images in a sample of adult participants in comparison to the conventional 3dMDface stereophotogrammetry system.

Material and methods

Twenty-nine adult participants were prospectively recruited. Eighteen soft tissue landmarks were marked on each participant's face before imaging. 3D facial images were captured using a 3dMDface system and the Apple iPhone TrueDepth NIR scanner combined with the Bellus3D Face app respectively. The best fit of each experimental model to the 3dMD scan was analyzed using Geomagic Control X software. The root mean square (RMS) was used to measure the "trueness" as the absolute deviation of each TrueDepth scan from the reference 3dMD image. Individual facial landmark deviations were also assessed to evaluate the reliability in different craniofacial regions. The "precision" of the smartphone was tested by taking 10 consecutive scans of the same subject and comparing those to the reference scan. Intra-observer and inter-observer reliabilities were assessed using the intra-class correlation coefficient (ICC).

Results

Relative to the 3dMDface system, the mean RMS difference of the iPhone/Bellus3D app was 0.86 ± 0.31 mm. 97% of all the landmarks were within 2 mm of error compared with the reference data. The ICC for intra-observer reproducibility or precision of the iPhone/Bellus3D app was 0.96, which was classified as excellent. The ICC for inter-observer reliability was 0.84, which was classified as good.

Conclusions

These results suggest that 3D facial images acquired with this system, the iPhone TrueDepth NIR camera in conjunction with the Bellus3D Face app, are clinically accurate and reliable. Judicious use is advised in clinical situations that require high degrees of detail due to a lack of image resolution and a longer acquisition time. Generally, this system possesses the potential to serve as a practical alternative to conventional stereophotogrammetry systems for use in a clinical setting due to its accessibility and relative ease of use and further research is planned to appraise its updated clinical use.

Three-dimensional quantitative analysis of temporal region morphology in Chinese young adult

Background

Temporal filling is commonly used to correct temporal depression. However, there is a lack of quantitative criteria for pre- and post-operative evaluations. The use of three-dimensional scanning may help improving the success of temporal filling by providing quantitative assessments. The study aimed to compare the results of qualitative morphological evaluation of the temporal region with a quantitative, numerical analysis of the temporal difference value (TDV).

Methods

We enrolled twenty-six male and forty-nine female volunteers aged 18 to 29 years. Facial images were acquired in OBJ format using 3dMD facial stereo-photography. The morphologies of the temporal regions were separately evaluated by four researchers in the form of two-dimensional (2D) images. Results were classified as either aesthetic or unaesthetic. The quantitative evaluation of the temporal region was then conducted. First, the temporal region was trimmed out from the original 3D image into a new OBJ file. Second, interpolation was used to construct a smooth, adapted surface. Third, a mathematical model of temporal region flatness denoted as the TDV, which was defined as the sum of the Euclidean distances of all 3D points between the constructed surface and the temporal-region OBJ file. The classification of each sample was compared with its TDV to verify the mathematical model's validity. The cutoff threshold and prediction accuracy of this mathematical model were calculated.

Results

The cutoff threshold between aesthetic and unaesthetic TDV was found to be 24.66 for males and 28.11 for females. The prediction accuracy rate was 0.73 for men and 0.73 for women.

Conclusion

The method has high overlap and good repeatability and minimizes the influence of subjective aesthetics on morphological judgment. TDV has a certain reference value for clinical temporal region evaluation.

Using a 3D asymmetry index as a novel form for capturing complex three-dimensionality in positional plagiocephaly

Positional plagiocephaly (PP) is the most common skull deformity in infants. Different classification systems exist for graduating the degree of PP, but all of these systems are based on two-dimensional (2D) parameters. This limitation leads to several problems stemming from the fact that 2D parameters are used to classify the three-dimensional (3D) shape of the head. We therefore evaluate existing measurement parameters and validate a newly developed 3D parameter for quantifying PP. Additionally, we present a new classification of PP based on a 3D parameter. 210 patients with PP and 50 patients without PP were included in this study. Existing parameters (2D and 3D) and newly developed volume parameters based on a 3D stereophotogrammetry scan were validated using ROC curves. Additionally, thresholds for the new 3D parameter of a 3D asymmetry index were assessed. The volume parameter 3D asymmetry index quantifies PP equally as well as the gold standard of 30° diagonal difference. Moreover, a 3D asymmetry index allows for a 3D-based classification of PP. The 3D asymmetry index can be used to define the degree of PP. It is easily applicable in stereophotogrammetric datasets and allows for comparability both intra- and inter-individually as well as for scientific analysis.

Facial scanning technologies in the era of digital workflow: A systematic review and network meta-analysis

PURPOSE

The aim of this network meta-analysis is to evaluate the accuracy of various face-scanning technologies in the market, with respect to the different dimensions of space (x, y, and z axes). Furthermore, attention will be paid to the type of technologies currently used and to the best practices for high-quality scan acquisition.

MATERIAL AND METHODS

The review was conducted following the PRISMA guidelines and its updates. A thorough search was performed using the digital databases MEDLINE, PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials by entering research lines or various combinations of free words. The main keywords used during the search process were "photogrammetry", "laser scanner", "optical scanner", "3D, and "face".

RESULTS

None of the included technologies significantly deviated from direct anthropometry. The obtained mean differences in the distances between the considered landmarks range from 1.10 to -1.74 mm.

CONCLUSION

Limiting the movements of the patient and scanner allows for more accurate facial scans with all the technologies involved. Active technologies such as laser scanners (LS), structured light (SL), and infrared structured light (ISL) have accuracy comparable to that of static stereophotogrammetry while being more cost-effective and less time-consuming.

A new method for quantification of frontal retrusion and complex skull shape in metopic craniosynostosis: a pilot study of a new outcome measure for endoscopic strip craniectomy

OBJECTIVE

The objective of this study was to propose a new skull outline-based method to objectively quantify complex 3D skull shapes and frontal and supraorbital retrusion in metopic craniosynostosis using 3D photogrammetry.

METHODS

A standard section from 3D photogrammetry, which represents the trigonocephalic shape, was used in this study. From the midpoint of the area of this section, half diagonals were calculated to the skull outline at 5° increments in the anterior half of the head. These half diagonals were used to create a sinusoidal curve, and the area under the sinusoidal curve (AUC) was used to represent the mathematical expression of the trigonocephalic head shape. The AUC from 0° to 180° (90° from the midline to each side) was calculated and is referred to as AUC0→180. The AUC from 60° to 120° (30° from the midline to each side) was also calculated and is referred to as AUC60→120. A total of 24 patients who underwent endoscopic strip craniectomy and 13 age- and sex-matched controls were included in the study. The AUC values obtained in patients at different time points and controls were analyzed.

RESULTS

The mean preoperative AUC60→120 and AUC0→180 in the patients were significantly lower than those in control individuals. The increase in both AUC60→120 and AUC0→180 values is statistically significant at the discontinuation of helmet therapy and at final follow-up. Receiver operating characteristic curve analysis indicated that AUC60→120 is a more accurate classifier than AUC0→180.

CONCLUSIONS

The proposed method objectively quantifies complex head shape and frontal retrusion in patients with metopic craniosynostosis and provides a quantitative measure for follow-up after surgical treatment. It avoids ionizing radiation exposure.

Investigating the Reliability of Novel Nasal Anthropometry Using Advanced Three-Dimensional Digital Stereophotogrammetry

Three-dimensional surface imaging systems (3DSI) provide an effective and applicable approach for the quantification of facial morphology. Several researchers have implemented 3D techniques for nasal anthropometry; however, they only included limited classic nasal facial landmarks and parameters. In our clinical routines, we have identified a considerable number of novel facial landmarks and nasal anthropometric parameters, which could be of great benefit to personalized rhinoplasty. Our aim is to verify their reliability, thus laying the foundation for the comprehensive application of 3DSI in personalized rhinoplasty. We determined 46 facial landmarks and 57 anthropometric parameters. A total of 110 volunteers were recruited, and the intra-assessor, inter-assessor, and intra-method reliability of nasal anthropometry were assessed through 3DSI. Our results displayed the high intra-assessor reliability of MAD (0.012-0.29, 0.003-0.758 mm), REM (0.008-1.958%), TEM (0-0.06), rTEM (0.001-0.155%), and ICC (0.77-0.995); inter-assessor reliability of 0.216-1.476, 0.003-2.013 mm; 0.01-7.552%, 0-0.161, and 0.001-1.481%, 0.732-0.985, respectively; and intra-method reliability of 0.006-0.598°, 0-0.379 mm; 0 0.984%, 0-0.047, and 0-0.078%, 0.996-0.998, respectively. This study provides conclusive evidence for the high reliability of novel facial landmarks and anthropometric parameters for comprehensive nasal measurements using the 3DSI system. Considering this, the proposed landmarks and parameters could be widely used for digital planning and evaluation in personalized rhinoplasty, otorhinolaryngology, and oral and maxillofacial surgery.

Longitudinal composite 3D faces and facial growth trends in children 6-11 years of age using 3D cephalometric surface imaging

BACKGROUND

Normative craniofacial anthropometry provides clinically important reference values used in the treatment of craniofacial conditions. Few objective datasets of normative data exist for children.

AIM

To establish normative data regarding craniofacial morphology changes with growth in children.

SUBJECTS AND METHODS

3D surface images of the same group of healthy children aged 6 - 11 years old recruited from a Dallas school were taken annually between the years 2015 - 2020. Composite 3D cephalometric faces were created for boys and girls of each age. General and craniofacial anthropometric measurements were compared.

RESULTS

Seven hundred ninety one individual stereophotogrammetric acquisitions were used (400 boys, 391 girls) taken from 180 children. Linear facial, orbital, nasal, and oral anthropometric measurements revealed a consistent increase in magnitude with age. Composite 3D face comparisons revealed prominent vertical and anteroposterior growth trends in the lower and upper facial regions.

CONCLUSION

This study presents a longitudinal 3D control dataset of the same group of children over a 6-year period that can serve as reference norms for facial growth values and trends in children aged 6-11 years. The composite 3D normative faces are available for clinical and research purposes upon request, which may be interrogated and measured according to user need and preference.

Effects of Positioning Errors Onto the Ratio and Angle Measurements in Photographs of Patients With Unilateral Cleft Lip and Palate

BACKGROUND

Nasolabial esthetics is 1 of the most important issues in the evaluation of treatment outcomes in patients with unilateral cleft lip and palate (CLP). Frontal and basal view photographs are commonly used to evaluate nasolabial esthetics in patients with unilateral CLP. High-quality photography plays an important role in evaluating the treatment outcomes and poor quality photographs can result in errors, whereas evaluating the treatment results. Facial proportions and angles are important in the esthetic perception of the face. Hence, this study aimed to determine the effects of positioning errors on the ratio and angle measurements in photographs of patients with unilateral CLP.

METHODS

In the clinical and computer environment, a mechanism was set up to take photos at standard and at different angles. A real-size unilateral CLP silicone doll was constructed for the photographs to be taken in the clinical setting. A test-retest was performed to determine the reliability of the measured values.

RESULTS

The correlation coefficients for the first measurement and remeasurement values were statistically significant; positive and strong correlations were obtained.

CONCLUSIONS

Based on the data obtained from our study, the angle and ratio measurements obtained from the two-dimensional photographs provided reliable results.

Standardized Three-Dimensional Lateral Distraction Test: Its Reliability to Assess Medial Canthal Tendon Laxity

Background

Assessment of MCT laxity is critical to the surgery options. Our study aimed to analyze the reliability of measuring medial canthal tendon (MCT) laxity by using a novel standardized three-dimensional lateral distraction test (3D-LDT).

Methods

Forty-eight Caucasian volunteers (25 males and 23 females, 96 eyes) between 22 and 84 years of age (55.6 ± 18.6 years old) were included in our study. From a neutral position, the lower eyelid was gently pulled laterally along a horizontal line to define the most distracted position of the lower punctum. Both in the neutral and distracted position, standardized 3D images were acquired for each subject by two observers, and each image were measured twice by two raters. Four landmarks and six corresponding linear measurements were evaluated for intra-rater, inter-rater, and inter-method reliability.

Results

Intra-rater, inter-rater and inter-method reliability analyses of 3D-LDT revealed an intraclass correlation of more than 95%, a mean absolute difference of less than 1 mm, and a technical error of measurement of less than 1 mm. Measurements of relative error (2.59–12.04%) and relative technical error (1.83–16.05%) for the inter-landmarks distance from pupil center to the lower punctum were higher than those from limbus nasal center to the lower punctum (6.13–30.39 and 4.34–26.85%, respectively).

Conclusions

This study provided high reliability of the three-dimensional lateral distraction test (3D-LDT) for assessing medial canthal tendon (MCT) laxity, which were never evaluated by digital imaging system.

Level of Evidence IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Three-Dimensional Anthropometry for Evaluating Reliability of Worm's Eye View Photographs of Unilateral Cleft Lip Nasal Deformity

BACKGROUND

Worm's eye view photograph has been widely used for anthropometric analysis. However, it is difficult to secure objectivity because it cannot be captured at a constant head-up degree. This study aimed to analyze whether anthropometric nasal measurements in worm's eye view differ from the actual values.

METHODS

A total of 40 patients with unilateral cleft lip nasal deformities were included. The 30° and 60° head-tilted two-dimensional (2D) photographs were captured from the three-dimensional (3D) images. The real measurements were obtained from 3D images and 2D measurements were obtained from the captured images. The cleft/non-cleft side ratios of the nostril height, width, and alar base width were compared between 3D and 2D images.

RESULTS

There was a significant difference in the nostril height between the 3D and 30° values (3D = 0.82, 30° = 0.92, P < 0.001) but no meaningful difference was noted between the 3D and 60° values (3D = 0.82, 60° = 0.84, P = 0.31). There was no significant difference in the nostril width among the 30°, 60°, and 3D values. A significant difference was found in the alar base width between the 3D values and both the 30° (3D = 0.998, 30° = 1.04, P = 0.026) and 60° (3D = 0.998, 30° = 1.03, P = 0.029) values.

CONCLUSIONS

This study demonstrates that 2D photographs do not accurately reflect actual values. The nostril height and alar width ratio can be changed depending on the head-up position. The 3D systems are more accurate and less affected by the subject's head position. Therefore, the 3D imaging system is advocated for the anthropometric analysis of unilateral cleft lip nasal deformity.

Three-dimensional facial scanner in the hands of patients: validation of a novel application on iPad/iPhone for three-dimensional imaging

Background

Three-dimensional (3D) photography plays an important role in surgical planning and postoperative evaluation. Commercial 3D facial scanners are expensive, and they require patients to come to the clinics for 3D photography. To solve this problem, we developed an iPad/iPhone application to enable patients to capture 3D images of themselves on their own. This study aimed to evaluate the validity and reproducibility of this novel imaging system.

Methods

3D images were taken on 20 volunteers using the novel imaging system. Twenty-one anthropometric parameters were measured using calipers (direct measurement) and 3D photographs (3D photogrammetry). The results were compared to assess the accuracy and bias of 3D photogrammetry. The reproducibility was evaluated by testing intra- and interobserver reliabilities. Furthermore, 3D virtual models obtained by the novel imaging system and Vectra H1 camera were compared by performing heat map analysis.

Results

The 3D photogrammetric results showed excellent correlations with direct measurements. Most anthropometric parameters did not show statistically significant differences between the two methods. The 95% limits of agreement exceeded 2 mm in some parameters, especially those with large numbers, although their relative error measurements were very small. Intra- and interobserver reliabilities were high enough to ensure good reproducibility. The comparison of 3D models obtained by the novel imaging system and Vectra H1 camera showed that the mean distance and the mean RMS were 0.08 and 0.67 mm, respectively.

Conclusions

The novel 3D facial scanning system is validated to enable patients to take 3D images on their own. The imaging quality of the subnasale region needs further improvement. Future clinical applications include surgical planning, postoperative evaluation, and early diagnosis of diseases that affect facial appearance.

A novel standardized distraction test to evaluate lower eyelid tension using three-dimensional stereophotogrammetry

Background

Standardized pre-operative assessment of the lower eyelid tension is essential to determine the optimal surgical technique. However, quantitative analysis using the conventional distraction test is inaccurate and user-dependent. Our purpose was to introduce a novel, standardized three-dimensional distraction test for measuring lower eyelid tension and to determine its standard values in a Caucasian population.

Methods

In 94 participants (50 men and 44 women; age 21-85 years), a 15.9-g weighted eyelid hook was used to pull down the lower eyelid. Two three-dimensional images were acquired with a VECTRA M3 stereophotogrammetry device-one in the neutral position without a hook and the other in the distracted position with the eyelid hook. The images of all participants in both positions were measured twice by a single observer.

Results

There was no clinical (>1 mm) or statistically significant difference between the two repeated measurements of all the inter-landmark linear distances in both positions (P≥0.05, respectively). The mean distracted displacement between the neutral and distracted position for margin reflex distance was 5.50±1.53 mm, without any age-specific difference (P=0.08); however, a significant gender-specific difference was observed as men had significantly greater displacement than women (P<0.001).

Conclusions

Our proposed standardized three-dimensional distraction test for assessing lower eyelid tension using an eyelid hook and a simple landmark-based system seems to provide high reliability. This novel and simple method might be helpful for the preoperative planning of eyelid surgeries.

Evaluating the agreement and reliability of a web-based facial analysis tool for rhinoplasty

PURPOSE

Rhinoplasty is one of the most common and challenging plastic surgery procedures. Facial analysis is a crucial step in planning. Utilizing three-dimensional (3D) model of a patient's face is an emerging way of performing facial analysis. This paper evaluates the agreement and reliability of facial measurements taken using a web app, located at digitized-rhinoplasty.com, that utilizes 3D models of the patient's face.

METHODS

Eleven measurements were calculated on 16 human subjects. Three methods of measurements were performed: direct measurements on human subjects' faces, measurements on 2D photographs, and measurements on 3D models of face scans. The Bland-Altman plot is used for testing the agreement between the web app and the well-known Blender 3D modeling software. Intra-rater and inter-rater reliability was calculated and compared for 2D and 3D methods using the intraclass correlation coefficient (ICC) method. The statistical analysis methods were checked for the normality and homoscedasticity assumptions.

RESULTS

The results indicate that the web app and Blender software show agreement within 95% confidence limits. The web app performs well in intra-rater and inter-rater reliability statistical analysis. The web app's reliability scores are consistently better than facial analysis software which was found highly reliable in a previous study. We also compare the methods of measurements in terms of time, ease of use, and cost.

CONCLUSION

The utilization of 3D computer modeling for facial analysis has its advantages and started to become more common due to recent advances in technology. The web app utilizes 3D face scans for pre-operative planning and post-operative evaluation of facial surgeries. The web app performs well in agreement and inter-/intra-reliability analysis and performs consistently better than software that works utilizing 2D photographs. The web app provides accurate, repeatable, affordable, and fast facial measurements for facial analysis when compared to direct and 2D methods.

Updating Standards of Facial Growth in Romanian Children and Adolescents Using the Anthropometric Method-A Pilot Study

The anthropometric method is an important tri-dimensional and non-invasive assessment instrument for accurate diagnosis in paedodontics, orthodontics, and other medical fields. Our aim was to propose a technique that is accessible for clinicians and to determine the reference values for Romanian children and adolescents for the facial parameters selected. We proposed three basic instruments: a plastic compass, a ruler, and a digital caliper. Eighty-five children and adolescents (62% girls and 38% boys), aged between 3.5 and 14.5 years, were included in the study. We selected eight transversal, 12 vertical, and three sagittal measurements. Facial indices, according to Farkas L.G., were directly determined. The correlations between facial and general growth parameters, using Pearson correlation coefficient, for the entire sample were significant, direct, and strong for the following: Zy-Zy, Go-Go, N-Gn, N-Sn, Sto-Gn, Tr-Gn, Tr-Sn, Tr-Tr (r = 0.526–0.925, p < 0.001), and insignificant for Sn-Sto (r = 0.099–0.124, p > 0.354). The highest correlation coefficient is exhibited by Tr-Gn (r = 0.893 with height and r = 0.925 with weight). When performing a gender related comparison, we noticed that the vertical and transversal linear parameters and some facial indices are increased in boys (p < 0.05), depending on the age group. The simplified anthropometric technique represents an accessible method to every clinician, bringing important information related to dentofacial growth, diagnosis, and treatment planning in dentistry.

Accuracy and Reliability of Kinect Motion Sensing Input Device’s 3D Models: A Comparison to Direct Anthropometry and 2D Photogrammetry

AIM: This study aims to evaluate the accuracy and reliability of Kinect motion sensing input device’s three-dimensional (3D) models by comparing it with direct anthropometry and digital 2D photogrammetry. MATERIALS AND METHODS: Six profiles and four frontal parameters were directly measured on the faces of 80 participants. The same measurements were repeated using two-dimensional (2D) photogrammetry and (3D) images obtained from Kinect device. Another observer made the same measurements for 30% of the images obtained with 3D technique, and interobserver reproducibility was evaluated for 3D images. Intraobserver reproducibility was evaluated. Statistical analysis was conducted using the paired samples t-test, interclass correlation coefficient, and Bland-Altman limits of agreement. RESULTS: The highest mean difference was 0.0084 mm between direct measurement and photogrammetry, 0.027 mm between direct measurement and 3D Kinect’s models, and 0.018 mm between photogrammetry and 3D Kinect’s. The lowest agreement value was 0.016 in the all parameter between the photogrammetry and 3D Kinect’s methods. Agreement between the two observers varied from 0.999 Sn-Me to 1 with the rest of linear measurements. CONCLUSION: Measurements done using 3D Images obtained from Kinect device indicate that it may be an accurate and reliable imaging method for use in orthodontics. It also provides an easy low-cost 3D imaging technique that has become increasingly popular in clinical settings, offering advantages for surgical planning and outcome evaluation.

Smile dimensions affect self-perceived smile attractiveness

Facial expressions play a leading role in human interactions because they provide signaling information of emotion and create social perceptions of an individuals’ physical and personality traits. Smiling increases socially perceived attractiveness and is considered a signal of trustworthiness and intelligence. Despite the ample information regarding the social importance of an attractive smile, little is known about the association between smile characteristics and self-assessed smile attractiveness. Here we investigate the effect of smile dimensions on ratings of self-perceived smile attractiveness, in a group of 613 young adults using 3D facial imaging. We show a significant effect of proportional smile width (ratio of smile width to facial width) on self-perceived smile attractiveness. In fact, for every 10% increase in proportional smile width, self-perceived attractiveness ratings increased by 10.26%. In the present sample, this association was primarily evident in females. Our results indicate that objective characteristics of the smile influence self-perception of smile attractiveness. The increased strength of the effect in females provides support to the notion that females are overall more aware of their smile and the impact it has on their public image.

Validating three-dimensional imaging for volumetric assessment of periorbital soft tissue

Purpose: To evaluate the accuracy and interobserver variability of three-dimensional (3D) stereophotogrammetric imaging for volumetric assessment in the periorbital region and to propose a protocol for measurement. Methods: A cross-sectional study was performed. Fifty-eight normal adult subjects had photographs taken using the VECTRA M3 imaging system on two separate occasions at a single center teaching hospital. The primary study outcome measurement was mean volume change in the periorbital region, using different methods of image analysis with the following variables: registration method, eyes open or closed, eyelids measured separately or together, extension of area measured to include mid-face. Accuracy was defined as the agreement between paired images with no measured change in volume (0 mL). The agreement between two independent observers was assessed using Bland-Altman plots. Results: There was a statistically significant difference (P < .0001) between the different methods of measurement, with registration of images having the most effect (partial eta squared 0.229). A mean change in volume of 0.11 ± 0.13 mL was reported for the most accurate method. Agreement between observers was confirmed (highest Intraclass Correlation Coefficient 0.63). Conclusions: Assessment of volumetric change in the periorbital region using 3D image reconstruction is accurate with good interobserver repeatability and is suitable for clinical use. A protocol for data acquisition using the VECTRA M3 is proposed. 3D image reconstruction holds promise to enable diagnosis, treatment monitoring, and surgical outcome evaluation in ocular adnexal disease.

Reliability of Periocular Anthropometry: A Comparison of Direct, 2-Dimensional, and 3-Dimensional Techniques

BACKGROUND

Three-dimensional (3D) imaging has become increasingly popular in aesthetic surgery. However, few studies have emphasized its application in the periocular region.

OBJECTIVE

To provide evidence supporting the reliability of generalizing periocular measurements obtained using caliper-derived direct anthropometry and 2-dimensional (2D) photogrammetry to 3D stereophotogrammetry.

MATERIALS AND METHODS

Periocular surfaces were captured using a stereophotogrammetry system for 46 normal Caucasian individuals. Twenty-two periocular variables were directly, 2-dimensionally, and 3-dimensionally measured. Reliability of these measurements was evaluated and compared with each other.

RESULTS

The results revealed that, for direct (intra-rater reliability only), 2D, and 3D anthropometry, overall intra-rater and inter-rater intraclass correlation coefficient estimates were 0.88, 0.99 and 0.97, and 0.98 and 0.92, respectively; mean absolute differences were 0.84 mm, 0.26 and 0.36 units, and 0.35 and 0.67 units, respectively; technical error of measurement (TEM) estimates were 0.85 mm, 0.25 and 0.36 units, and 0.32 and 0.65 units, respectively; relative error measurement estimates were 6.46%, 1.69% and 2.74%, and 1.67% and 5.11%, respectively; and relative TEM estimates were 6.25%, 1.62% and 2.78%, and 2.12% and 5.12%, respectively.

CONCLUSION

Stereophotogrammetry and the authors' landmark location protocol yield very good reliability for a series of 2D and 3D measurements.

Three-Dimensional Stereophotogrammetry in the Evaluation of Craniosynostosis: Current and Potential Use Cases

ABSTRACT

Three-dimensional (3D) stereophotogrammetry is a novel imaging technique that has gained popularity in the medical field as a reliable, non-invasive, and radiation-free imaging modality. It uses optical sensors to acquire multiple 2D images from different angles which are reconstructed into a 3D digital model of the subject's surface. The technique proved to be especially useful in craniofacial applications, where it serves as a tool to overcome the limitations imposed by conventional imaging modalities and subjective evaluation methods. The capability to acquire high-dimensional data in a quick and safe manner and archive them for retrospective longitudinal analyses, provides the field with a methodology to increase the understanding of the morphological development of the cranium, its growth patterns and the effect of different treatments over time.This review describes the role of 3D stereophotogrammetry in the evaluation of craniosynostosis, including reliability studies, current and potential clinical use cases, and practical challenges. Finally, developments within the research field are analyzed by means of bibliometric networks, depicting prominent research topics, authors, and institutions, to stimulate new ideas and collaborations in the field of craniofacial 3D stereophotogrammetry.We anticipate that utilization of this modality's full potential requires a global effort in terms of collaborations, data sharing, standardization, and harmonization. Such developments can facilitate larger studies and novel deep learning methods that can aid in reaching an objective consensus regarding the most effective treatments for patients with craniosynostosis and other craniofacial anomalies, and to increase our understanding of these complex dysmorphologies and associated phenotypes.

Nasal Alar Surface Area Differences After Unilateral Cleft Lip Repair: Long-Term Effects of the Perialar Incision

BACKGROUND

The Millard rotation-advancement cleft lip repair is the most commonly performed cleft lip repair. An extended perialar incision allows for further advancement of the lateral lip element and improved positioning of the alar base. There is a lack of data evaluating differences in nasal alar growth when the perialar incision is utilized. This study compares the long-term effects of a perialar incision on the alar surface area of unilateral cleft lip patients who underwent a Millard cleft lip repair.

METHODS

Thirty-seven patients with a diagnosis of unilateral cleft lip treated with a Millard primary lip repair were studied. A perialar incision was utilized in 16 patients while 21 patients underwent a standard Millard repair. 3dMD facial images were taken at least 10 years after the initial lip repair. Using the patient's non-cleft side as an internal control, the Alar Ratio (AR) was calculated, defined as the cleft alar surface area divided by the non-cleft alar surface area.

RESULTS

The AR was significantly greater in the standard Millard repair group compared to the perialar incision group, 0.74 and 0.64 respectively (P = .02). The incomplete cleft population demonstrated a more profound difference between the treatment groups (0.82 and 0.62, respectively).

CONCLUSIONS

This study reveals an association between a perialar incision and decreased alar surface area. Long-term follow up results suggest a perialar scar restricts alar growth leading to significant asymmetry between the cleft and non-cleft sides. Therefore, surgical technique must be carefully considered prior to utilizing a perialar incision during unilateral cleft lip repair.

A novel approach quantifying the periorbital morphology: A comparison of direct, 2-dimensional, and 3-dimensional technologies

BACKGROUND

The measurement of anatomical structures is critical in plastic and reconstructive surgery. However, few detailed and standardized measurements have been widely used in the periorbital region. This study aimed to evaluate the feasibility of a novel detailed and standardized protocol with 2D and 3D technologies, and explore the relationship between them and direct measurements.

METHODS

Fifty healthy Caucasians (100 eyes) between 20 and 68 years old were recruited and captured for 3D photographs by VECTRA M3 3D Imaging System. Subsequently, 24 landmarks were located on each 3D photographs following a standardized protocol, and then 19 linear and 3 angular periorbital variables were measured. Furthermore, two-dimensional (2D) and direct measurements were conducted on each subject and compared with 3D measurements and one another.

RESULTS

The grand r means across all measurements were 0.77, 0.78, and 0.88 for direct vs. 2D values, direct vs. 3D values, and 3D vs. 2D values, respectively. The mean absolute differences were 1 mm (ranging from 0.2 mm to 3.7 mm) between direct and 3D measurements, 1 mm (ranging from 0.04 mm to 2.4 mm) between direct and 2D measurements, and 1 mm and 6.6° (ranging from 0.04 mm or 0.5° to 3 mm or 12.8°) between 2D and 3D measurements.

CONCLUSIONS

This study verified the feasibility of this detailed and standardized landmark localization protocol for assessing the periorbital morphology with 2D and 3D technologies. This protocol may work as a bridge communicating with all studies involving any of the three technologies in the future.

Virtual anthropology? Reliability of three-dimensional photogrammetry as a forensic anthropology measurement and documentation technique

Osseous remains provide forensic anthropologists with morphological and osteometric information that can be used in building a biological profile. By conducting a visual and physical examination, an anthropologist can infer information such as the sex and age of the deceased. Traditionally, morphological and osteometric information is gathered by physically handling remains for analysis. With the advancement of digital technology, there has been a shift from direct to indirect methods of analysis by utilizing models generated from three-dimensional (3D) imaging, which includes computed tomography (CT) scanning and 3D photogrammetry. Although CT scanning is more common, photogrammetry has found application in a range of fields such as architecture, geography and road accident reconstruction. The application of modern-day photogrammetry for forensic anthropology purposes, however, has not been discussed extensively. The aim of this research was to validate the accuracy of 3D models generated by photogrammetry by comparing them to both 3D models generated by CT scanning and the actual physical models. In this study, six 3D models were created using photogrammetry (n = 3) and CT scanning (n = 3). The 3D models were generated from three different Bone Clone® human skulls. A mobile phone camera was used to capture images, which were then processed in Agisoft Metashape®. Intrarater, interrater, and intermethod reliability tests gave correlation coefficients of at least 0.9980, 0.9871, and 0.9862, respectively; rTEM results ranged from 0.250 to 6.55%; and an analysis of variance (ANOVA) yielded P values under 0.05 for all measurements except one. Statistical tests therefore showed photogrammetry to be a reliable and accurate alternative to more expensive CT scanning approaches.

Comparison of Head Shape Outcomes in Metopic Synostosis Using Limited Strip Craniectomy and Open Vault Reconstruction Techniques

AIM

Metopic craniosynostosis (MCS), with its trigonocephalic head shape, is often treated with either limited incision strip craniectomy (LISC) followed by helmet orthotic treatment, or open cranial vault reconstruction techniques (OCVR). There is controversy regarding resultant shape outcomes among craniofacial surgeons. Those adverse to LISC claim normal head shape is never attained, while proponents believe there is gradual correction to an equivalent outcome. This study aims to quantitate, over time, the three-dimensional (3D) head shapes in patients who have undergone LISC or OCVR intervention for MCS.

METHODS

Sixty-three 3D images of 26 patients with MCS were analyzed retrospectively. Head shape analyses were performed at: (1) preoperative, (2) 1-month postoperative, (3) 10 to 14 months postoperative (1 year), and (4) 2 years postoperative. Composite 3D head shapes of patients were compared at each time point. Two-dimensional (2D) standardized cross sections of the forehead were also compared.

RESULTS

Composite head shapes for both groups were nested, to allow visual comparison as the child's forehead grows and expands. The difference between LISC and OCVR 2D cross sections was calculated; 108.26 mm preoperatively, 127.18 mm after 1-month postoperative, 51.05 mm after 10 to 14 months postoperative, and 27.03 mm after 2 years postoperative.

CONCLUSIONS

This study found excellent head shape outcomes for both the LISC and OCVR techniques at 2 years of age. It also corroborates the slow and progressive improvement in head shape with the LISC technique. This study highlights the advantages of 3D photography for measurement of contour outcomes, utilizing both 2D vector and 3D whole head analytical techniques.

Three-Dimensional Analysis of Bilateral Cleft Lip and Palate Nasal Deformity

OBJECTIVE

This cross-sectional study utilizes 3-dimensional analysis to assess nasal morphology in patients with bilateral cleft lip and palate (BCLP) compared to controls across the timeline of cleft care.

DESIGN

Retrospective comparative cross-sectional study.

SETTING

Tertiary pediatric academic institution.

PATIENTS AND PARTICIPANTS

One hundred and twelve patients with BCLP and an equal number of age and sex-matched control participants.

MAIN OUTCOME MEASURE(S)

Nasolabial angle, nasal length, nasal protrusion, columella length, columella width, nasal tip width, alar width, and alar base width were collected at each time point. The measurements were collected pre-nasoalveolar molding (NAM) therapy, post-NAM therapy, post-primary cleft rhinoplasty, 1 year, 5 years, 10 years, and 15 years of age.

RESULTS

Nasolabial angle and nasal tip width were significantly different from controls from pre-NAM through 15 years of age time points. Nasal length was not significantly different at any time point. Alar width and alar base width were significantly different from pre-NAM through 10 years of age time points. Nasal protrusion, columella length, and columella width were significantly different from pre-NAM through 5 years of age time points.

CONCLUSIONS

This study demonstrates that three-dimensional photogrammetry is effective in assessing the changes in nasal morphology that occur throughout the course of care in patients with BCLP from before cleft lip repair to the completion of nasal growth.

Validity and reproducibility of the 3D VECTRA photogrammetric surface imaging system for the maxillofacial anthropometric measurement on cleft patients

OBJECTIVES

To validate the accuracy and reproducibility of linear measurements of three-dimensional (3D) images and to compare the measurements with the direct anthropometry method on cleft lip and palate (CLP) patients.

MATERIALS AND METHODS

Nineteen linear facial measurements were derived from 16 standardized surface landmarks obtained from 37 cleft patients (20 males, 17 females; mean age 23.84 years, standard deviation ± 6.02). They were taken manually with calipers and were compared with the digitally calculated distance on the 3D images captured using the VECTRA-M5 360° Imaging System with pre-marked landmarks. Another pair of 19 linear measurements were computed on the 3D images 2 weeks apart for intra- and inter-observer agreements. Statistical analyses used were paired t test, the Bland-Altman analysis, and the intra-class correlation coefficient (ICC) index.

RESULTS

Most of the linear measurements showed no statistically significant differences between the proposed method and direct anthropometry linear measurements. Nevertheless, bias of the 3D imaging system is present in the linear measurements of the nose width and the upper vermillion height. The measurements' mean biases were within 2 mm, but the 95% limit of agreement was more than 2 mm. Intra- and inter-observer measurements generally showed good reproducibility. Four inter-observer measurements, the upper and lower face heights, nose width, and pronasale to left alar base were clinically significant.

CONCLUSIONS

Measurements obtained from this 3D imaging system are valid and reproducible for evaluating CLP patients.

CLINICAL RELEVANCE

The system is suitable to be used in a clinical setting for cleft patients. However, training of the operator is strictly advisable.

Reliability of periocular anthropometry using three-dimensional digital stereophotogrammetry

PURPOSE

Non-invasive three-dimensional (3D) stereophotogrammetry is becoming increasingly popular in many fields. However, few studies have focused on its periocular application. We aimed to provide evidence for the periocular application of a novel anthropometric procedure using 3D stereophotogrammetry by evaluating its reliability.

METHODS

Fifty-one Caucasians were recruited (102 eyes; mean age, 31.9 ± 13.6 years). Two sets of 3D images were acquired for each subject, and two measurement sessions were performed on each image by two raters. Fifty-two periocular landmarks were identified, and then 49 corresponding linear, curvilinear, and angular measurements were evaluated for intrarater, interrater, and intramethod reliability.

RESULTS

Our findings showed highly reliable results for mean absolute difference (0.59 and 0.68 unit), relative error measurement (2.66% and 3.08%), technical error of measurement (0.59 and 0.66 unit), relative technical error of measurement (2.71% and 2.96%), and intraclass correlation coefficient (0.98) for intrarater 1 and intrarater 2 reliability; respectively 0.94 unit, 4.06%, 0.89 unit, and 3.94%, as well as 0.97 for interrater reliability; and respectively 0.98 unit, 4.66%, 0.96 unit, and 4.64%, as well as 0.96 for intramethod reliability.

CONCLUSIONS

This imaging system and the landmark identification protocol are highly reliable. The collected measurements and their errors can be applied for the comparison of reliability among various 3D imaging systems and populations. It could be utilized for planning surgeries and evaluating treatment outcomes for physicians in ophthalmology, plastic and esthetic surgery, and in the maxillofacial field where periocular morphology alterations are made.

Effect of skin tone on the accuracy of hybrid and passive stereophotogrammetry

BACKGROUND

Three-dimensional (3D) surface images acquired from stereophotogrammetry are increasingly being used to plan or evaluate treatment by plastic surgeons. Stereophotogrammetry exists in active, passive, and hybrid forms. Active and hybrid stereophotogrammetry are believed to capture darker surfaces more accurately than passive stereophotogrammetry. The purpose of this study was to investigate whether skin tone has a clinically relevant effect on the accuracy of hybrid and passive stereophotogrammetry.

MATERIALS AND METHODS

Seven subjects with different skin tones were recruited. 3D-printed face and breast were spray-painted in six different colors, ranging from white to black. The skin tones and paint colors were objectified by measuring their melanin index. 3D photos of the subjects and 3D prints were acquired with hybrid and passive stereophotogrammetry. These 3D photos were matched with specialized software, and their geometric differences were calculated.

RESULTS

None of the 3D photos showed a clinically relevant mean inaccuracy. On the 3D prints, hybrid stereophotogrammetry resulted in a smaller standard deviation of the inaccuracies than passive stereophotogrammetry (0.20 ± 0.06 mm vs. 0.35 ± 0.07 mm, p < 0.001). Passive stereophotogrammetry yielded a correlation between the melanin index of the spray paint colors and the standard deviation of the inaccuracy (Pearson's R = 0.60, p = 0.04). On human subjects, no correlation or difference in standard deviation of the accuracy was found.

CONCLUSION

Skin tone does not influence the accuracy of hybrid and passive 3D stereophotogrammetry in a clinically relevant way.

Smile dimensions in adult African American and Caucasian females and males

OBJECTIVES

To test smile dimension variations in adult African American and Caucasian females and males.

SETTING AND SAMPLE POPULATION

The University of Alabama at Birmingham School of Dentistry and Hospital. Three hundred and ninety-four participants were recruited; African American females and males distributed over five age groups: 20-30, 30-40, 40-50, 50-60 and older than 60.

MATERIAL & METHODS

Three-dimensional surface imaging was used to acquire two images of each participant, one at rest and one upon smile. Landmarks were plotted on the lips and linear distances measured to assess the length of the upper and lower lips, mouth width at rest and upon smile, gingival and dental display upon smile.

RESULTS

Linear dimensions are larger in males than in females, and in African Americans than in Caucasians, except for the length of the upper lip that does not differ between male African American and Caucasian males, in any given age group. Gingival display and dental display decrease with age in all groups.

CONCLUSION

Norms should reflect race, age and sex in order to optimize treatment goals.

Anthropometric Evaluation of Periorbital Region and Facial Projection Using Three-Dimensional Photogrammetry

INTRODUCTION

Direct anthropometric and three-dimensional (3D) photogrammetry measurements have been used extensively in cleft/craniofacial surgery to assess morphological changes and surgical outcomes. Craniofacial procedures alter the sagittal projection of periorbital bony prominences. Mulliken described a method of measuring their projection relative to the corneal plane but is impractical in clinical practice. Three-dimensional photogrammetry may offer a solution; however, the cornea is not visualized on this. The authors propose to develop new normative measurements of facial projection relative to the pupil.

METHODS

Five 3D photographs were taken of 5 individuals using Vectra M5 camera. Facial projection measurements were taken of the sagittal projection of the bilateral periorbital landmarks and nasal radix relative to the pupil using Mirror 3D analysis. Standard deviations (SD) were determined for each subject and laterality. Chi-square tests confirmed all SD <1 mm. Intra and inter-rater reliability were confirmed with an intraclass correlation coefficient assessment.

RESULTS

Three male and 2 female subjects were photographed with 5 unique images. Standard deviations of repeat measures of all landmarks were <0.5 mm. Chi-square tests confirmed with statistical significance that SD for all values except for the radix was <1 mm (P<0.05). Intrarater reliability was high for all landmarks (intraclass correlation coefficient coefficients 0.93-0.99). Inter-rater reliability was good for the lateral canthi and excellent for all others.

CONCLUSION

This technique demonstrates repeatability with high reliability on serial photographs and is applicable to measuring surgery effects and growth on facial projection. Establishment of age-specific normative values for landmark projection will refine usage applicability in operative planning.

Accuracy evaluation of tridimensional images performed by portable stereophotogrammetric system

Abstract Introduction Human facial characteristics vary according to individual dental occlusion, facial harmony, orofacial musculature and the format and configuration of craniofacial structures. Traditionally, anthropometric measurements have been acquired through direct evaluation of subjects in a clinical environment using calipers and metric tapes to measure distances between arches and landmarks. Scientific breakthroughs have enabled the digitization of data and introduced the possibility of quick, precise, radiation-free acquisitions; details can be archived for future analysis and easily shared with patients and colleagues. Among new facial analysis methods, the stereophotogrammetry technique has emerged, which uses a group of cameras to take many photographs of a subject in rapid succession from multiple angles. Nowadays, portable stereophotogrammetric systems are being proposed, as they are more practical and easier to use. Objective The aim of this work was to analyze the accuracy and reproducibility of a portable 3D stereophotogrammetric system (Vectra H1, Canfield, Fairfield, NJ, USA) in measuring soft facial tissues of 30 participants, defining measures of a cube and comparing these measurements with those obtained by a set 3D stereophotogrammetric system (Vectra M3, Canfield, Fairfield, NJ, USA) with previously validated accuracy and reproducibility through quantitative analysis of possible errors. Material and method Thirty temporary landmarks were used to measure (in mm) 34 distances in 30 participants (n = 30). Regarding the cube, 12 angles and 9 linear distances were evaluated. Result The results obtained by the established methodology indicated that the Vectra H1 portable system has shown accuracy and reproducibility equal to that of the Vectra M3 set system. Conclusion Data analysis and correlation to literature findings show Vectra H1's capability to reliably capture tridimensional images, which makes it practical for use in diverse clinical applications.

Anthropometric Analysis of the External Nose of the Egyptian Males

OBJECTIVE

The aim of this study was to describe average nasal anthropometric measurements for young Egyptian males by using the Rhinobase^® software.

MATERIALS AND METHODS

This was a cross-sectional study involving the evaluation of facial photographs. Frontal, right lateral and basal photographs for 300 healthy adult male Egyptian volunteers (n = 300) were taken; then, the photos were edited using Rhinobase^® Software and CorelDraw graphics (2017) software. Twenty anthropometric landmarks were determined. The calculated measurements of the soft tissue of the external nose included ten linear measurements and five angles.

RESULTS

The means of the linear measurements of the external nose in this study were as follows: nasal height (56.12 mm), nasal bridge length (47.0 mm), columella length (9.1 mm), alar length (29.3 mm), morphological nose width (41.0 mm), anatomical nose width (38.0 mm), nasal tip protrusion (21.0 mm), nasal tip projection using 'Goode's method' (29.36 mm), dorsum width (9.6 mm) and nasion height (2.04 mm). The means of the angular measurements of the nose were as follows: nasofacial angle (33.1°), nasofrontal angle (144.0°), nasolabial angle (104.5°), nasomental angle (127.6°) and mentocervical angle (104.7°).

CONCLUSIONS

Racial differences of the external nasal anthropometric values exist; hence, it is important to establish the average anthropometric measures for several races and ethnic groups. Measurements collected in this study can serve as a database for anthropometric average values of the external nose in healthy adult Egyptian males. Moreover, these measurements can aid in planning prior to nasal reconstruction and esthetic rhinoplasty by serving as a reference standard. Although the Rhinobase^® software is an easy, reliable and safe indirect method for nasal analysis, we should be cautious during interpretation of some edited landmarks on Rhinobase^® software pictures. In addition, inserting two rulers (in the horizontal and vertical dimension) allows accurate assessment of the linear anthropometric measurements.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Three-dimensional imaging of soft and hard facial tissues in patients with craniofacial syndromes: a systematic review of methodological quality

OBJECTIVES

To systematically review the methodological quality of three-dimensional imaging studies of patients with craniofacial syndromes and to propose recommendations for future research.

METHODS

PubMed, Embase and Cochrane databases as well as Grey literature were electronically searched. Inclusion criteria were patients with genetic syndromes with craniofacial manifestations and three-dimensional imaging of facial soft and/or hard tissues. Exclusion criteria consisted of non-syndromic conditions or conditions owing to environmental causes, injury or trauma, facial soft and hard tissues not included in the image analysis, case reports, reviews, opinion articles. No restrictions were made for patients' ethnicity nor age, publication language or publication date. Study quality was evaluated using the Methodological Index for Non-Randomized Studies (MINORS).

RESULTS

The search yielded 2228 citations of which 116 were assessed in detail and 60 were eventually included in this review. Studies showed a large heterogeneity in study design, sample size and patient age. An increase was observed in the amount of studies with time, and the imaging method most often used was CT. The most studied craniofacial syndromes were Treacher Collins, Crouzon and Apert syndrome. The articles could be divided into three main groups: diagnostic studies (34/60, 57%), evaluation of surgical outcomes (21/60, 35%) and evaluation of imaging techniques (5/60, 8%). For comparative studies, the median MINORS score was 13 (12-15, 25-75th percentile), and for non-comparative studies, the median MINORS score was 8 (7-9, 25-75th percentile).

CONCLUSIONS

The median MINORS scores were only 50 and 54% of the maximum scores and there was a lack of prospective, controlled trials with sufficiently large study groups. To improve the quality of future studies in this domain and given the low incidence of craniofacial syndromes, more prospective multicentre controlled trials should be set up.

Validation of the Vectra H1 portable three-dimensional photogrammetry system for facial imaging

Three-dimensional (3D) surface imaging using stereophotogrammetry has become increasingly popular in clinical settings, offering advantages for surgical planning and outcome evaluation. The handheld Vectra H1 is a low-cost, highly portable system that offers several advantages over larger stationary cameras, but independent technical validation is currently lacking. In this study, 3D facial images of 26 adult participants were captured with the Vectra H1 system and the previously validated 3dMDface system. Using error magnitude statistics, 136 linear distances were compared between cameras. In addition, 3D facial surfaces from each system were registered, heat maps generated, and global root mean square (RMS) error calculated. The 136 distances were highly comparable across the two cameras, with an average technical error of measurement (TEM) value of 0.84mm (range 0.19-1.54mm). The average RMS value of the 26 surface-to-surface comparisons was 0.43mm (range 0.33-0.59mm). In each case, the vast majority of the facial surface differences were within a ±1mm threshold. Areas exceeding ±1mm were generally limited to facial regions containing hair or subject to facial microexpressions. These results indicate that 3D facial surface images acquired with the Vectra H1 system are sufficiently accurate for most clinical applications.

Pursuing Mirror Image Reconstruction in Unilateral Microtia: Customizing Auricular Framework by Application of Three-Dimensional Imaging and Three-Dimensional Printing

BACKGROUND

Advances in three-dimensional imaging and three-dimensional printing technology have expanded the frontier of presurgical design for microtia reconstruction from two-dimensional curved lines to three-dimensional perspectives. This study presents an algorithm for combining three-dimensional surface imaging, computer-assisted design, and three-dimensional printing to create patient-specific auricular frameworks in unilateral microtia reconstruction.

METHODS

Between January of 2015 and January of 2016, six patients with unilateral microtia were enrolled. The average age of the patients was 7.6 years. A three-dimensional image of the patient's head was captured by 3dMDcranial, and virtual sculpture carried out using Geomagic Freeform software and a Touch X Haptic device for fabrication of the auricular template. Each template was tailored according to the patient's unique auricular morphology. The final construct was mirrored onto the defective side and printed out with biocompatible acrylic material.

RESULTS

During the surgery, the prefabricated customized template served as a three-dimensional guide for surgical simulation and sculpture of the MEDPOR framework. Average follow-up was 10.3 months. Symmetric and good aesthetic results with regard to auricular shape, projection, and orientation were obtained. One case with severe implant exposure was salvaged with free temporoparietal fascia transfer and skin grafting.

CONCLUSIONS

The combination of three-dimensional imaging and manufacturing technology with the malleability of MEDPOR has surpassed existing limitations resulting from the use of autologous materials and the ambiguity of two-dimensional planning. This approach allows surgeons to customize the auricular framework in a highly precise and sophisticated manner, taking a big step closer to the goal of mirror-image reconstruction for unilateral microtia patients.

CLINCIAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Hypertelorism and Orofacial Clefting Revisited: An Anthropometric Investigation

OBJECTIVE

Since the 1960s, multiple studies have reported a tendency toward hypertelorism in individuals with nonsyndromic orofacial clefts (OFCs). However, the association between specific cleft types and increased interorbital distance has been inconsistent. Using three-dimensional (3D) surface imaging, we tested whether different forms of clefting showed evidence of increased interorbital distance.

METHODS

Intercanthal and outercanthal distances and intercanthal indices were calculated from 3D facial surface images of 287 individuals with repaired OFCs. Raw measurements were converted to sex and age-normalized Z-scores. Mean Z-scores for individuals with cleft lip (CL), cleft lip and palate (CLP), and cleft palate (CP) were compared with reference normative values (controls) and one another directly using t tests and analysis of variance.

RESULTS

The CLP group showed a significant increase in intercanthal width (P = .001) and intercanthal index (P < .001) compared with reference norms. The CP group showed a significant decrease (P < .001) in outercanthal width. The CL group showed no difference from reference norms. The proportion of clinically hyperteloric individuals was generally low but highest in the CLP group (7.4%). Cleft severity had little effect on interorbital spacing.

CONCLUSIONS

Individuals with CLP exhibited on average a tendency toward mild hypertelorism, driven primarily by an increase in intercanthal distance. This tendency was not seen in CL or CP.

Reliability of Nasofacial Analysis Using Rhinobase® Software

OBJECTIVE

Rhinoplasty is a constant challenge for the surgeon, where the correct evaluation of facial aesthetic parameters allows harmonic changes appropriate for each patient. The aim of this study was to compare the preoperative and postoperative results of nasofacial analysis, performed by Rhinobase® software (indirect anthropometry) compared with direct anthropometry (caliper), in patients undergoing aesthetic rhinoplasty.

METHODS

The authors assessed the reliability of using Rhinobase® software for measuring nasofacial characteristics in 20 individuals (18 F, 2 M). In each patient, the nasofacial analysis was performed before and after surgery. Two raters performed indirect anthropometry on each image on two separate occasions.

RESULTS

Intrarater and interrater reliability for most indirect anthropometric measurements had intraclass correlation coefficients greater than 0.8. Regarding intermethod reliability, Pearson correlation coefficients ranged from 0.6 to 0.9 for most measurements. The highest correlation was found in interalar width, chin vertical, and lower facial height. The Cronbach's α coefficient calculated for all measurements was 0.8.

CONCLUSIONS

The Rhinobase® software is an easy and safe method for facial analysis. This study provides evidence of high reliability for several nasofacial measurements. The nasofacial analysis allows an accurate preoperative evaluation, surgical planning, and analysis of outcomes in rhinoplasty and may be a useful tool for both novice and experienced surgeons.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.