Cost-effective 3D documentation device in forensic medicine.

3D documentation in forensics and forensic medicine is being introduced more frequently in various institutes around the world. However, several institutes lack capacity in finances as well as staff to perform 3D documentations regularly. This technical paper aims to present a 3D documentation device that is low cost and easy to use and is a viable entry level solution for forensic medical departments. For this the small single-board computer Raspberry Pi 4 was used in conjunction with its high quality (HQ) camera module to create the 3DLamp - a flexible, low cost and easy to use documentation device. Besides a detailed description of the device this paper also presents four case examples where a 3D documentation was performed and analyses the acquired data and the created 3D models. It was found that the device returns feasible 3D models that appear usable for forensic 3D reconstructions.

An investigation of the reproducibility of a self-selected natural feet position when standing: Implications for the assessment of upright standing posture.

BACKGROUND: Photogrammetry is often used to evaluate standing static postural alignment. Patients are often instructed to self-select a natural feet position but it's unclear whether this position can be consistently replicated across repeated assessments. OBJECTIVE: To determine whether people can replicate a self-selected natural feet position in upright standing across three sessions on different days. DESIGN: Between days test-retest reliability. SETTING: University laboratory. METHODS: Three variables - Base of Support (BoS), Foot Width (FW), Feet Opening Angle (FOA) - were measured from foot tracings of 150 participants (18-30 years) using established procedures. BoS data were assessed for systematic bias (Analysis of Variance), and absolute (Coefficient of Variation - CV%) and relative (Intraclass Correlation Coefficient - ICC) reliability. RESULTS: There was systematic bias in the BoS data across the three testing sessions. The CV% for the BoS data was 15.2%. The ICC (95% CI) for the BoS data was 0.84 (0.79-0.87). There were moderate-large correlations between the BoS and both FOA and FW respectively within each session. CONCLUSION: If clinicians want to allow patients to use their self-selected natural feet position for repeated photogrammetric assessment of their static postural alignment it would be better to standardise the position of the feet, for example, by creating a tracing of a patient's self-selected natural feet position.

Smartphone Photogrammetric Assessment for Head Measurements.

The assessment of cranial deformation is relevant in the field of medicine dealing with infants, especially in paediatric neurosurgery and paediatrics. To address this demand, the smartphone-based solution PhotoMeDAS has been developed, harnessing mobile devices to create three-dimensional (3D) models of infants' heads and, from them, automatic cranial deformation reports. Therefore, it is crucial to examine the accuracy achievable with different mobile devices under similar conditions so prospective users can consider this aspect when using the smartphone-based solution. This study compares the linear accuracy obtained from three smartphone models (Samsung Galaxy S22 Ultra, S22, and S22+). Twelve measurements are taken with each mobile device using a coded cap on a head mannequin. For processing, three different bundle adjustment implementations are tested with and without self-calibration. After photogrammetric processing, the 3D coordinates are obtained. A comparison is made among spatially distributed distances across the head with PhotoMeDAS vs. ground truth established with a Creaform ACADEMIA 50 while-light 3D scanner. With a homogeneous scale factor for all the smartphones, the results showed that the average accuracy for the S22 smartphone is -1.15 ± 0.53 mm, for the S22+, 0.95 ± 0.40 mm, and for the S22 Ultra, -1.8 ± 0.45 mm. Worth noticing is that a substantial improvement is achieved regardless of whether the scale factor is introduced per device.

Comparison of Manual (2D) and Digital (3D) Methods in the Assessment of Simulated Facial Edema.

BACKGROUND: An edema assessment following dental surgeries is essential to improving the dental surgeon's technique and, consequentially, patient comfort. PURPOSE: Two-dimensional (2D) methods are limited in analyzing 3-dimensional (3D) surfaces. Currently, 3D methods are used to investigate postoperative swelling. However, there are no studies that directly compare 2D and 3D methods. The goal of this study is to directly compare 2D and 3D methods used in the assessment of postoperative edema. STUDY DESIGN AND SAMPLE: The investigators implemented a prospective, cross-sectional study with each subject serving as its own control. The sample was composed of dental student volunteers without facial deformities. PREDICTOR VARIABLE: The predictor variable is the method used to measure edema. After simulating edema, manual (2D) and digital (3D) techniques were used to measure edema. The manual method used direct facial perimeter measurements. The two digital methods were photogrammetry using a smartphone (iPhone 11, Apple Inc, Cupertino, California), and facial scanning with a smartphone application (Bellus3D FaceApp, Bellus3D Inc, Campbell, California) [3D measurements] MAIN OUTCOME VARIABLE: The coefficient of variation (CV) (CV = standard deviation /mean) was used to assess homogeneity of edema measurements. ANALYSIS: The Shapiro-Wilk and equal variance tests were applied to assess data homogeneity. Next, one-way analysis of variance was performed, followed by a correlation analysis. Finally, the data were submitted to Tukey's test. The statistical significance threshold was set at 5% (P < .05). RESULTS: The sample was composed of 20 subjects aged 18-38 years. The CV showed higher values using the manual (2D) method (47%; 4.88% ± 2.99), compared with the photogrammetry method (18%; 8.55 mm ± 1.52) and the smartphone application (21%; 8.97 mm ± 1.93). A statistically significant difference was observed between the manual method values and those of the other two groups (P < .001). There was no difference between the facial scanning and photogrammetry groups (3D methods) (P = .778) CONCLUSION AND RELEVANCE: Both digital measuring methods (3D) demonstrated greater homogeneity than the manual method in analyzing facial distortions caused by the same swelling simulation. Therefore, it can be affirmed that digital methods may be more reliable that manual methods for assessing facial edema.

Intra and interrater reliability for lower limb flexibility assessment using photogrammetry.

INTRODUCTION: Photogrammetry represents an advancement in the flexibility evaluation, and although it was highly explored for postural assessment, there is a scarcity of studies analyzing lower limb angular measurements using it. The purpose of this study is to verify the reliability of intrarater and interrarater photogrammetry in assessing lower limb flexibility. METHODS: This was a randomized cross-sectional observational study with test-retest design and a two-day interval. Thirty healthy, physically active adults were included. Three novice raters assessed the participants through flexibility tests of iliopsoas, hamstring, quadriceps and gastrocnemius on two occasions, and independently analyzed the captured images to establish reliability. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal detectable change (MDC) were calculated. RESULTS: Intrarater reliability was excellent for iliopsoas (ICC = 0.96; SEM = 1.4; MDC = 3.8), hamstring (ICC = 0.99; SEM = 1.1; MDC = 3.1), quadriceps (ICC = 0.99; SEM = 0.8; MDC = 2.3) and gastrocnemius (ICC = 0.98; SEM = 0.9; MDC = 2.5). Interrater reliability was excellent for iliopsoas (ICC = 0.94; SEM = 1.7; MDC = 4.6) and gastrocnemius (ICC = 0.91; SEM = 2.1; MDC = 5.8), but good for hamstring (ICC = 0.90; SEM = 2.8; MDC = 7.9) and quadriceps (ICC = 0.85; SEM = 3.0; MDC = 8.3). CONCLUSIONS: The excellent intrarater and good to excellent interrater reliability suggest that photogrammetry assessment of lower limb flexibility by novice raters is reliable. However, clinicians should consider the higher threshold of range of motion change necessary to outweigh measurement error due to interrater variability.

Cloner 3D photogrammetric facial scanner: Assessment of accuracy in a controlled clinical study.

OBJECTIVE: To evaluate the accuracy of facial measurements on three-dimensional images obtained using a new photogrammetric scanner. MATERIAL AND METHODS: A total of 11 participants were included in the study. Nine customized adhesive labels were used to identify the facial landmarks: Trichion (Tri), Glabella (G), Right (Exr) and Left (Exl), Pronasal (Pn), Subnasal (Sn), Chelion right (Chr) and left (Chl) and Mentonian (Me). Two trained and calibrated examiners were responsible for performing seven linear measurements for each participant (Tri-G, Sn-Me, Exr-Exl, Chr-Chl, Exr-Chr, Exl-Chl, Pn-Sn) first with a digital caliper and later with a three-dimensional model obtained after digitalization with photogrammetric technology. The intraclass correlation coefficient (ICC), mean difference, SD, and Bland-Altman correlation were used to compare the measurements performed. RESULTS: Intra and inter-examiner reliability were excellent (ICC >0.9). In general, the measurements presented a variation of a minor 2.0 mm. However, only three measures (Sn-Me, Exr-Exl, and Exr-Chr) were outside the clinical acceptability range. CONCLUSIONS: The 3D Cloner scanner showed clinically acceptable accuracy comparable to the digital caliper with a variation of -0.8 ± 1.2 mm. Inter- and intra-examiner agreement on digital measurements was also observed. CLINICAL SIGNIFICANCE: Scanners with accurate 3D model reproductions associated with reliable digital measurements provide a more precise diagnosis and better planning in orofacial treatment.

Accuracy of low-cost alternative facial scanners: a prospective cohort study.

INTRODUCTION: Three-dimensional facial scans have recently begun to play an increasingly important role in the peri-therapeutic management of oral and maxillofacial and head and neck surgery cases. Face scan images can be generated by optical facial scanners utilizing line-laser, stereophotography, or structured light modalities, as well as from volumetric data: for example, from cone beam computed tomography (CBCT). This study aimed to evaluate whether two low-cost procedures for the creation of three-dimensional face scan images were capable of producing sufficiently accurate data sets for clinical analysis. MATERIALS AND METHODS: Fifty healthy volunteers were included in the study. Two test objects with defined dimensions (Lego bricks) were attached to the forehead and the left cheek of each volunteer. Facial anthropometric values (i.e., the distances between the medial canthi, the lateral canthi, the nasal alae, and the angles of the mouth) were first measured manually. Subsequently, face scans were performed with a smart device and manual photogrammetry and the values obtained were compared with the manually measured data sets. RESULTS: The anthropometric distances deviated, on average, 2.17 mm from the manual measurements (smart device scanning deviation 3.01 mm, photogrammetry deviation 1.34 mm), with seven out of eight deviations being statistically significant. For the Lego brick, from a total of 32 angles, 19 values demonstrated a significant difference from the original 90° angles. The average deviation was 6.5° (smart device scanning deviation 10.1°, photogrammetry deviation 2.8°). CONCLUSION: Manual photogrammetry demonstrated greater accuracy when creating three-dimensional face scan images; however, smart devices are more user-friendly. Dental professionals should monitor camera and smart device technical improvements carefully when choosing and adequate technique for 3D scanning.

Evaluation of accuracy of photogrammetry with 3D scanning and conventional impression method for craniomaxillofacial defects using a software analysis.

BACKGROUND: Facial mutilation and deformities can be caused by cancer, tumours, injuries, infections, and inherited or acquired deformities and has the potential to degrade one's quality of life by interfering with fundamental tasks like communication, breathing, feeding, and aesthetics. Depending on the type of defect, producing maxillofacial prostheses for the rehabilitation of patients with various defects can be challenging and complex. The prosthesis is used to replace missing or damaged parts of the cranium and face, like the nose, auricle, orbit, and surrounding tissues, as well as missing areas of soft and hard tissue, with the primary goal of increasing the patient's quality of life by rehabilitating oral functions such as speech, swallowing, and mastication. Traditional maxillofacial prosthesis impression and fabrication processes include a number of complicated steps that are costly, time-consuming, and uncomfortable for the patient. These rely on the knowledge of the maxillofacial team, dental clinicians, and maxillofacial technician. The foundation of the impression is the keystone for creating a prosthesis. However, this is the most time-consuming and difficult chair-side operation in maxillofacial prosthesis manufacturing since it requires prolonged interaction with the patient. The field of prosthesis fabrication is being transformed by the digital revolution. Digital technology allows for more accurate impression data to be gathered in less time (3 to 5 min) than traditional methods, lowering patient anxiety. Digital impressions eliminate the need for messy impression materials and provide patients with a more pleasant experience. This method bypasses the procedure of traditional gypsum model fabrication. This eliminates the disparity caused by a dimensional distortion of the impression material and gypsum setting expansion. Traditional dental impression processes leave enough room for errors, such as voids or flaws, air bubbles, or deformities, while current technology for prosthesis planning has emerged as an alternative means to improve patient acceptability and pleasure, not only because the end result is a precisely fitted restoration but also because the chair-side adjustments required are reduced. The most frequent approaches for creating 3D virtual models are the following. To begin, 3D scanning is employed, in which the subjects are scanned in three dimensions, and the point cloud data is used to create a virtual digital model. METHODS: It will be a hospital-based randomised control trial, carried out at the Department of Prosthodontics, Sharad Pawar Dental College, Sawangi (Meghe), Wardha, a part of Datta Meghe Institute of Medical Sciences (Deemed University). A total of 45 patients will be selected from the outpatient department (OPD) of the Department of Prosthodontics. All the patients will be provided written consent before their participation in the study. METHODOLOGY: 1. Patient screening will be done, and the patient will be allocated to three techniques that are the conventional manual method, photogrammetry method, and 3D scanning in a randomised manner 2. The impression of the defect will be recorded by conventional manual method, photogrammetry method, and 3D scanning 3. The defect will be modelled in three ways: first is as per the manual dimension taken on the patient, second is the organisation of photographic image taken with lab standards and third is plotting of point cloud data to generate the virtual 3D model 4. For photogrammetric prosthesis design, finite photos/images will be taken at multiple angles to model the 3D virtual design. With the use of minimum photographs, the 3D modelling can be performed by using freeware, and a mould is obtained 5. The CAD software was used to design the prosthesis, and the final negative mould can be printed using additive manufacturing 6. The mould fabricated by all three methods will be analysed by a software using reverse engineering technology Study design: Randomised control trial Duration: 2 years Sample size: 45 patients DISCUSSION: Rodrigo Salazar-Gamarra1, Rosemary Seelaus, and Jorge Vicente Lopes da Silva et al., in the year 2016, discussed, as part of a method for manufacturing face prostheses utilising a mobile device, free software, and a photo capture protocol, that 2D captures of the anatomy of a patient with a facial defect were converted into a 3D model using monoscopic photogrammetry and a mobile device. The visual and technical integrity of the resulting digital models was assessed. The technological approach and models that resulted were thoroughly explained and evaluated for technical and clinical value. Marta Revilla-León, Wael Att, and Dr Med Dent et al. (2020) used a coordinate measuring equipment which was used to assess the accuracy of complete arch implant impression processes utilising conventional, photogrammetry, and intraoral scanning. Corina Marilena Cristache and Ioana Tudor Liliana Moraru et al. in the year 2021 provided an update on defect data acquisition, editing, and design using open-source and commercially available software in digital workflow in maxillofacial prosthodontics. This research looked at randomised clinical trials, case reports, case series, technical comments, letters to the editor, and reviews involving humans that were written in English and included detailed information on data acquisition, data processing software, and maxillofacial prosthetic part design. TRIAL REGISTRATION: CTRI/2022/08/044524. Registered on September 16, 2022.

Accuracy assessment of UAV-post-processing kinematic (PPK) and UAV-traditional (with ground control points) georeferencing methods.

The use of unmanned aerial vehicles (UAV) in photogrammetric mapping/surveying facilities has increased recently due to the developments on photogrammetric instruments and algorithms that enhance high-quality final products (orthoimages, digital surface model-DSM, etc.) in fast, accurate, and economical way. The aim of this study was to assess the accuracy of a UAV-based post-processing kinematic (PPK) solution. To do that, two methods were implemented with PPK solution and georeferencing with ground control points (GCPs). According to the statistical results, root mean square error (RMSE) values obtained from the GCPs and PPK solutions in the horizontal component are 6.5 cm and 5.4 cm, respectively. The RMSE values in the vertical component (ellipsoidal heights) were obtained as 4.8 cm (GCPs) and 5.2 cm (PPK), respectively. The results show that UAV-PPK method can also be used to produce photogrammetric products where high accuracy (≤ 10 cm) is required without GCPs. In addition, the results obtained regarding the use of this method clearly show that it can be applied in many different fields such as agriculture, forestry, natural disasters, and geomatics.

A semi-automatic three-dimensional technique using a regionalized facial template enables facial growth assessment in healthy children from 1.5 to 5.0 years of age.

Objectives: To develop a semi-automatic technique to evaluate normative facial growth in healthy children between the age of 1.5 and 5.0 years using three-dimensional stereophotogrammetric images. Materials and Methods: Three-dimensional facial images of healthy children at 1.5, 2.0, 2.5, 3.0, 4.0 and 5.0 years of age were collected and positioned based on a reference frame. A general face template was used to extract the face and its separate regions from the full stereophotogrammetric image. Furthermore, this template was used to create a uniform distributed mesh, which could be directly compared to other meshes. Average faces were created for each age group and mean growth was determined between consecutive groups for the full face and its separate regions. Finally, the results were tested for intra- and inter-operator performance. Results: The highest growth velocity was present in the first period between 1.5 and 2.0 years of age with an average of 1.50 mm (±0.54 mm) per six months. After 2.0 years, facial growth velocity declined to only a third at the age of 5.0 years. Intra- and inter-operator variability was small and not significant. Conclusions: The results show that this technique can be used for objective clinical evaluation of facial growth. Example normative facial averages and the corresponding facial growth between the age 1.5 and 5.0 years are shown. Clinical Relevance: This technique can be used to collect and process facial data for objective clinical evaluation of facial growth in the individual patient. Furthermore, these data can be used as normative data in future comparative studies.

Asymmetry index for the photogrammetric assessment of facial asymmetry.

INTRODUCTION: Facial asymmetry is common and can be clinically related to dental malocclusion, facial bone development, muscular imbalance, and soft tissues thickness, which should be assessed during diagnosis to choose proper treatment options. This study aimed to quantify the amount of symmetry/asymmetry in previously defined symmetrical and asymmetrical subjects, analyzing full-face 3-dimensional images. METHODS: Seventy-six orthodontic patients' 3-dimensional face images were obtained with the 3dMD Trio-system (Atlanta, Ga) and processed with the Geomagic Control (64-bit; 3D Systems, Rock Hill, SC) software. Patients were divided into symmetrical and asymmetrical groups through a surface-based technique. Sixteen facial landmarks were positioned, an asymmetry index was calculated for each landmark, and an evaluation diagram of facial asymmetry was created through the asymmetry index mean and standard deviation of symmetrical and asymmetrical landmarks. RESULTS: The asymmetry index mean varied from 0.05 to 1.51 in the symmetrical group and from 0.05 to 2.84 in the asymmetrical group. This study suggests that landmarks located in the lower third of the face have a greater asymmetry index than other landmarks. CONCLUSIONS: The landmark-based technique does not exhibit statistically significant differences among asymmetrical and symmetrical patients for some landmarks. This approach provides useful information about the localization and the extension of asymmetry, in which bilateral landmarks showed a higher amount of asymmetry than median landmarks.

Performance Assessment of Reference Modelling Methods for Defect Evaluation in Asphalt Concrete.

The deterioration of road conditions and increasing repair deficits pose challenges for the maintenance of reliable road infrastructure, and thus threaten, for example, safety and the fluent flow of traffic. Improved and more efficient procedures for maintenance are required, and these require improved knowledge of road conditions, i.e., improved data. Three-dimensional mapping presents possibilities for large-scale collection of data on road surfaces and automatic evaluation of maintenance needs. However, the development and, specifically, evaluation of large-scale mobile methods requires reliable references. To evaluate possibilities for close-range, static, high-resolution, three-dimensional measurement of road surfaces for reference use, three measurement methods and five instrumentations are investigated: terrestrial laser scanning (TLS, Leica RTC360), photogrammetry using high-resolution professional-grade cameras (Nikon D800 and D810E), photogrammetry using an industrial camera (FLIR Grasshopper GS3-U3-120S6C-C), and structured-light handheld scanners Artec Leo and Faro Freestyle. High-resolution photogrammetry is established as reference based on laboratory measurements and point density. The instrumentations are compared against one another using cross-sections, point-point distances, and ability to obtain key metrics of defects, and a qualitative assessment of the processing procedures for each is carried out. It is found that photogrammetric models provide the highest resolutions (10-50 million points per m2) and photogrammetric and TLS approaches perform robustly in precision with consistent sub-millimeter offsets relative to one another, while handheld scanners perform relatively inconsistently. A discussion on the practical implications of using each of the examined instrumentations is presented.

Stereophotogrammetric head shape assessment in neonates is feasible and can identify distinct differences between term-born and very preterm infants at term equivalent age.

The development of head shape and volume may reflect neurodevelopmental outcome and therefore is of paramount importance in neonatal care. Here, we compare head morphology in 25 very preterm infants with a birth weight of below 1500 g and / or a gestational age (GA) before 32 completed weeks to 25 term infants with a GA of 37-42 weeks at term equivalent age (TEA) and identify possible risk factors for non-synostotic head shape deformities. For three-dimensional head assessments, a portable stereophotogrammetric device was used. The most common and distinct head shape deformity in preterm infants was dolichocephaly. Severity of dolichocephaly correlated with GA and body weight at TEA but not with other factors such as neonatal morbidity, sex or total duration of respiratory support. Head circumference (HC) and cranial volume (CV) were not significantly different between the preterm and term infant group. Digitally measured HC and the CV significantly correlated even in infants with head shape deformities. Our study shows that stereophotogrammetric head assessment is feasible in all preterm and term infants and provides valuable information on volumetry and comprehensive head shape characteristics. In a small sample of preterm infants, body weight at TEA was identified as a specific risk factor for the development of dolichocephaly.

Technological innovation in the recovery and analysis of 3D forensic footwear evidence: Structure from motion (SfM) photogrammetry.

The recovery of three-dimensional footwear impressions at crime scenes can be a challenge but can also yield important investigative data. Traditional methods involve casting 3D impressions but these methods have limitations: the trace is usually destroyed during capture; the process can be time consuming, with a risk of failure; and the resultant cast is bulky and therefore difficult to share and store. The use of Structure from Motion (SfM) photogrammetry has been used widely to capture fossil footprints in the geological record and while there is a small body of work advocating its use in forensic practice the full potential of this technique has yet to be realised in an operational context. The availability of affordable software is one limiting factor and here we report the availability of a bespoke freeware for SfM recovery and subsequent analysis of for footwear evidence (DigTrace). Our aim here is not to provide a rigorous comparison of SfM methods to other recovery methods, but more to illustrate the potential while also documenting the typical workflows and potential errors associated with an SfM based approach. By doing so we hope to encourage further research, experimentation and ultimately adoption by practitioners.

Sparse Visual-Inertial Measurement Units Placement for Gait Kinematics Assessment.

This study investigates the possibility of estimating lower-limb joint kinematics and meaningful performance indexes for physiotherapists, during gait on a treadmill based on data collected from a sparse placement of new Visual Inertial Measurement Units (VIMU) and the use of an Extended Kalman Filter (EKF). The proposed EKF takes advantage of the biomechanics of the human body and of the investigated task to reduce sensor inaccuracies. Two state-vector formulations, one based on the use of constant acceleration model and one based on Fourier series, and the tuning of their corresponding parameters were analyzed. The constant acceleration model, due to its inherent inconsistency for human motion, required a cumbersome optimisation process and needed the a-priori knowledge of reference joint trajectories for EKF parameters tuning. On the other hand, the Fourier series formulation could be used without a specific parameters tuning process. In both cases, the average root mean square difference and correlation coefficient between the estimated joint angles and those reconstructed with a reference stereophotogrammetric system was 3.5deg and 0.70, respectively. Moreover, the stride lengths were estimated with a normalized root mean square difference inferior to 2% when using the forward kinematics model receiving as input the estimated joint angles. The popular gait deviation index was also estimated and showed similar results very close to 100, using both the proposed method and the reference stereophotogrammetric system. Such consistency was obtained using only three wireless and affordable VIMU located at the pelvis and both heels and tracked using two affordable RGB cameras. Being further easy-to-use and suitable for applications taking place outside of the laboratory, the proposed method thus represents a good compromise between accurate reference stereophotogrammetric systems and markerless ones for which accuracy is still under debate.

Computer photogrammetry as a postural assessment in Schwartz-Jampel syndrome: A case report.

The Schwartz-Jampel Syndrome (SJS) is a rare genetic disorder characterized by myotonia and bone dysplasia, which may change the posture. The subject of this case report was a seven-year-old boy diagnosed with SJS and presenting generalized muscle and joints contractures. The purpose of the present case report was to identify postural asymmetries in a patient with SJS through photogrammetry. Postural analysis was conducted using photogrammetry with the Postural Assessment Software (SAPO®). Photogrammetry is a postural assessment system performed through photographic images. These images are acquired by camera and transported to the computer. SAPO® software performs the assessment of this photograph throughout 3D analysis and compares with a predefined protocol. The results of the present case report document several recurrent postural imbalances seen in SJS including myotonia, facial dysmorphism, and skeletal deformities. Thus, even with little evidence in the literature, physical therapy treatment is indicated to increase the functionality of the individual.

Assessment of facial symmetry by three-dimensional stereophotogrammetry after mandibular reconstruction: A comparison with subjective assessment.

INTRODUCTION: The assessment of facial symmetry, after mandibular reconstruction, currently relies on subjective esthetic assessment by an evaluator. The present study aimed to compare conventional subjective assessment with quantitative evaluation by three-dimensional (3D) stereophotogrammetry of facial cosmetic symmetry. METHODS: This retrospective study enrolled 20 patients who underwent mandibular reconstruction with free fibula flap after segmental resection between 2014 and 2018. Subjective assessments were performed by seven clinicians at 6-12 months after surgery. Simultaneously, lower face symmetry was measured by 3D stereophotogrammetry with the VECTRA H1 system and recorded as the root mean square deviation (RMSD). Data from the subjective and quantitative evaluations were compared using Spearman's rank correlation coefficient. RESULTS: The results showed that subjective assessments were strongly and negatively correlated with RMSD (P=0.00000128). This confirmed that RMSD, obtained by 3D stereophotogrammetry, reflected the subjective assessment of symmetry in our cohort. CONCLUSIONS: Three-dimensional stereophotogrammetry of facial cosmetic symmetry will be an available quantitative method for patients with head and neck cancer after mandibular reconstruction.

Three-dimensional scanners for soft-tissue facial assessment in clinical practice.

INTRODUCTION: The quantitative assessment of facial appearance and function is critical in the process of restoring normality and thus minimising morbidity in patients with facial deformities. Three-dimensional (3D) scanners have increasingly been applied in clinical settings to circumvent the issues associated with standard approaches, namely, subjectivity. This study aimed to summarise the current literature on the accuracy, reliability, and usability of 3D scanning technologies for soft-tissue facial assessment. METHODOLOGY: Medline, EMBASE, and Web of Science were searched for studies assessing the accuracy, reliability, and/or clinical usability of 3D scanners in assessing facial morphology. All results were filtered by title, abstract, and finally by full text for relevance. RESULTS: Eight hundred and thirty-seven results were filtered down to 41 articles that were included in this review. Articles were categorised depending on the 3D visualising principle of the scanner being tested: laser-based scanning, stereophotogrammetry, structured-light scanning, or RGB-D (red, green, blue-depth) sensors. DISCUSSION: Of the traditional 3D scanners evaluated in the literature, stereophotogrammetric systems most consistently demonstrate excellent accuracy and reliability in the collection of 3D facial scans. Due to their cost, size, and complexity, these systems are often unsuitable for incorporation into clinical environments with limited availability of resources, space, and time. Recently developed RGB-D sensors can collect accurate static and dynamic 3D facial scans without many of these disadvantages. Still, further improvements in their technical specifications and a greater focus on the development of automated facial assessment software is needed before RGB-D sensors can be universally accepted as a new gold-standard for soft-tissue facial assessment.

Long-Term Photogrammetric- and Panel Assessment-Based Outcome Study of Staged Reconstructive Approach for Hypertelorism Correction.

BACKGROUND: The surgical management of hypertelorism is challenging for plastic surgeons, and limited long-term outcome data are available. The purpose of this long-term study was to report a single-surgeon experience with a staged reconstructive protocol for hypertelorism correction. METHODS: This retrospective study reviewed the records of patients with hypertelorism who were surgically managed by a single surgeon between 1978 and 2000. Bone (orbital box osteotomy and orthognathic surgery) and soft tissue (rhinoplasty and epicanthoplasty) surgeries were performed based on a patient-specific surgical protocol. Included patients were divided into a childhood group and an adolescence or adulthood group according to their age at orbital repositioning (≤12 and >12 years, respectively). Patients were invited for clinical interviews in February 2020 to evaluate whether requests for revision surgery had been made. The photogrammetric analysis-based hypertelorism index was calculated at preoperative and long-term postoperative times. Satisfaction with the long-term outcome was judged by both surgical professionals and laypeople. RESULTS: In total, 14 patients with hypertelorism of different etiologies were included, with no request for revision surgery during an average follow-up of 29 years. The preoperative hypertelorism index was higher than the long-term postoperative evaluation (all, P < 0.05) for both childhood and adolescence or adulthood groups. Intergroup comparison revealed no significant difference for the hypertelorism index and panel assessment-based satisfaction with long-term outcome analysis (all, P > 0.05). CONCLUSIONS: Considering the complexity and wide spectrum of clinical presentation of soft tissue and bone deformities in hypertelorism and current outcomes, the surgical approach to these patients should be staged and individualized for achievement of a balanced result between functional (orbital, occlusion, and psychosocial) and aesthetic parameters.

A comparative assessment of external morphological traits between Macaca munzala, Tawang and Macaca assamensis, Goalpara population in Northeast India.

The present study aimed to conduct a comparative assessment of the external morphology, relative tail length and colour variation (RGB additive colour model) of Macaca munzala, Tawang and Macaca assamensis, Goalpara (southern Brahmaputra population), using a non-invasive photogrammetry method. The study revealed that the relative tail length of M. munzala (0.43 ± 0.03) is similar to that of M. assamensis assamensis, a subspecies of M. assamensis. On the other hand, the relative tail length of M. assamensis, Goalpara (0.61 ± 0.04) is similar to M. assamensis pelops, the other subspecies of M. assamensis. A total of 12 external morphological traits were observed and similarities found between the two studied populations. The study also found that the species-specific traits of M. munzala such as "dark patch of the crown whorl", "dark patch of hair at the temporal side", "spectacle appearance around eyes" and "whip-like tail appearance" in the infant and "stocky tail" are present in M. assamensis, Goalpara as well. Likewise, the "chin and cheek whiskers" are found in adult female individuals of both species. The comparative assessment of the dorsal coat colour (RGB value) revealed a darker brown dorsal coat in M. munzala (R 123.14 ± 11.62; G 107.71 ± 10.37, B 89.43 ± 9.21) than in M. assamensis, Goalpara (R 136 ± 23.57, G 112 ± 15.63, B 97.83 ± 13.04). The comparative assessment of facial skin colour among the adult individuals showed that the male M. munzala has darker brown facial skin than that of M. assamensis, whereas the female M. munzala shows darker reddish facial skin compared to M. assamensis, Goalpara. The species-specific traits of M. leucogenys were also compared, and the traits "chin and cheek whiskers", "darker dorsal coat" and "round penile" appearance have a striking resemblance to those of the M. munzala population of Tawang. Thus, the external morphological traits that are being used to distinguish these macaque species are highly variable even within the same species, and there is an urgent need to identify more precise species-specific morphological traits.