Accuracy and reproducibility of a 3-dimensional stereophotogrammetric imaging system

Smartphone applications for facial scanning: A technical and scoping review

INTRODUCTION

Facial scanning through smartphone scanning applications (SSA) is increasingly being used for medical applications as cost-effective, chairside method. However, clinical validation is lacking. This review aims to address: (1) Which SSA could perform facial scanning? (2) Which SSA can be clinically used? (3) Which SSA have been reported and scientifically validated for medical applications?

METHODS

Technical search for SSA designed for face or object scanning was conducted on Google, Apple App Store, and Google Play Store from August 2022 to December 2023. Literature search was performed on PubMed, Cochrane, EMBASE, MEDLINE, Scopus, IEEE Xplore, ACM Digital Library, Clinicaltrials.gov, ICTRP (WHO) and preprints up to 2023. Eligibility criteria included English-written scientific articles incorporating at least one SSA for clinical purposes. SSA selection and data extraction were executed by one reviewer, validated by second, with third reviewer being consulted for discordances.

RESULTS

Sixty-three applications designed for three-dimensional object scanning were retrieved, with 52 currently offering facial scanning capabilities. Fifty-six scientific articles, comprising two case reports, 16 proof-of-concepts and 38 experimental studies were analysed. Thirteen applications (123D Catch, 3D Creator, Bellus 3D Dental Pro, Bellus 3D Face app, Bellus 3D Face Maker, Capture, Heges, Metascan, Polycam, Scandy Pro, Scaniverse, Tap tap tap and Trnio) were reported in literature for digital workflow integration, comparison or proof-of-concept studies.

CONCLUSION

Fifty-two SSA can perform facial scanning currently and can be used clinically, offering cost-effectiveness, portability and user-friendliness. Although clinical validation is crucial, only 13 SSA were scientifically validated, underlying awareness of potential pitfalls and limitations.

Reduction of masseter muscle prominence after treatment with onabotulinumtoxinA: Primary results from a randomized phase 2 study

BACKGROUND

OnabotA is used to treat masseter muscle prominence (MMP).

OBJECTIVE

To assess the safety and efficacy of OnabotA for MMP in a randomized study.

METHODS

This 12-month, multicenter, double-blind, placebo-controlled, phase 2 study randomized adults (18-50 years of age) with marked/very marked bilateral MMP (≥4 on the Masseter Muscle Prominence Scale [MMPS]) to OnabotA (24, 48, 72, or 96 U) or placebo; retreatment occurred at day 180 if MMPS ≥4. Lower facial volume at day 90 was measured using Vectra 3-dimensional photography. Safety assessments included computed tomography and dental exams. Evaluations occurred monthly through day 360.

RESULTS

Among 187 randomized subjects, significant lower facial volume reductions and percentage of responders (MMPS grade ≤3) were greater with OnabotA versus placebo at day 90 (P < .001 and ≤.008, respectively). Similar efficacy was observed with retreatment. No dose-related safety trends or clinically relevant changes in the mandible or teeth occurred. Localized impact on smile was reported with 96 U OnabotA (n = 4).

LIMITATIONS

Limited sample size per individual treatment group.

CONCLUSION

OnabotA administered in 1 or 2 treatments over 1 year was associated with significant reductions in masseter muscle volume and MMP severity, with an acceptable safety profile.

Measuring the esthetic outcome using a three-dimensional facial scanner after parotidectomy and application of vascularized fat flaps

BACKGROUND

Parotidectomy can affect facial symmetry. Our study evaluated the symmetry of different facial areas and upper neck after total parotidectomy and filling the area with vascularized fat flap (VFF).

METHODS

Facial symmetry was evaluated in eight patients and a control group matched in terms of gender and age, using a three-dimensional (3D) facial scanner. The operated side was compared with the non-operated side and the symmetry compared with that of the control group. Scanning was performed either within the first year (group 1; n = 5) or after 3 years (group 2; n = 3) postoperatively.

RESULTS

The patients' cheek and neck areas were found to be significantly more asymmetric, but the cheek area in group 2 was significantly more symmetrical when compared with group 1.

CONCLUSION

VFF appeared to achieve similar facial symmetry to the matched non-operated group. Time had a positive impact on the facial symmetry. The neck area was the most asymmetric, and proved to be unreliable, regardless of whether any procedure was performed or not.

The Validity of a Smartphone-Based Method for Acquiring 3D Images of the Face

Objectives. To evaluate the accuracy and reproducibility of measurements obtained using the Bellus3D Face Application on a mobile smartphone by comparing them to direct measurements on pre-marked and blank face scans. Materials and Methods. Twenty-five healthy young adults (six males and nineteen females; age range 20-30 years) were included in this prospective cross-sectional study, with the only exclusion criterion being the presence of significant facial hair interfering with the placement and visualization of landmarks. Image acquisitions were performed using an iPhone XR with the Bellus3D FaceApp face scanning application, an iOS application for smartphones. Ten single midfacial and five paired bilateral landmarks were defined and marked. Two face scans were performed on each patient, both on blank and marked faces, and distances were measured directly with calipers and digitally. Results. The random error values were 1.0 mm and 0.4 mm for the manual point placement and measurements and virtual point placement on blank faces, respectively. The two methods used (the direct method and acquisition on faces with landmarks) demonstrate relatively similar reliability (ICC > 0.8); however, a paired t-test showed that the differences between several measurements were statistically significant (p < 0.05). Regardless of the method used, there was a systematic error for various values that included the nose and mouth (p < 0.05). The measurements demonstrating the most significant differences between the methods were those that included the tip of the nose, with the mean differences being -4.4-3.3 mm. The measurements of the distances that estimate face "depth" showed the greatest consistency irrespective of the tested method (p > 0.05 and ICC > 0.8). Conclusions. The use of the Bellus3D FaceApp is precise and reproducible for certain areas of the face, but digital reconstruction errors prohibit, for the time being, the use of this technology in everyday clinical practice. The noted discrepancies were consistent and more prevalent for specific areas such as the tip of the nose. Further investigations are required to determine other sources of error and for other smartphone-based applications released for 3D face image acquisitions.

Evaluating 3D Simulation Accuracy for Breast Augmentation Outcomes: A Volumetric and Surface Contour Analysis in Chinese Patients

BACKGROUND

The use of three-dimensional imaging in breast augmentation with silicone implants has revolutionized the surgery planning process by providing detailed visualizations of expected post-surgical outcomes. This technology enhances the decision-making process, enabling patients to choose their implants with greater confidence and ultimately leading to higher satisfaction with the postoperative outcome.

OBJECTIVE

This study aims to assess the accuracy of 3D imaging simulations using the Canfield Vectra XT 3D system in predicting breast augmentation outcomes in Chinese patients, focusing on volume, surface contour, breast anterior-posterior (AP) Projection, and breast internal angle.

METHODS

Our study analyzed female patients who received breast augmentation, documenting their preoperative and three-month postoperative conditions with 3D Vectra XT system images. Exclusions were made for patients undergoing concurrent breast surgeries or those with tuberous or ptotic breasts, due to limitations of the imaging system. Implants used were either round textured or anatomically shaped cohesive silicone gel, inserted subpectorally through trans-axillary or inframammary incisions, based on personalized evaluations. A detailed comparison between preoperative simulations and actual postoperative outcomes was conducted, focusing on volume, surface contour, AP projection, and internal angle variations. Statistical significance was determined through paired T tests, P < 0.05.

RESULTS

In the analysis of preoperative simulations for determining postoperative outcomes in breast surgery, our study involving 42 Chinese patients, a total of 84 breasts, was conducted. The results indicated a mean volumetric discrepancy of 21.5 ± 10.3 (SD) cubic centimeters between the simulated and actual postoperative outcomes, achieving an accuracy rate of 91.9%. The root mean square deviation for the breast surface geometry was calculated to be 4.5 ± 1.1 (SD) millimeters (mm), demonstrating a low variance between the predicted and observed outcomes. The investigation found no significant variations across any specific areas of the breast surface, highlighting the uniform accuracy of the simulations across the entire breast. Additionally, the mean differences in Anterior-Posterior (AP) projection and internal angle were determined to be 8.82 ± 5.64 mm and 0.48 ± 1.91 (SD) degrees, respectively. These findings collectively attest to the efficacy of preoperative simulations in accurately predicting the postoperative physical appearance of breasts, thereby providing a valuable tool for surgical planning and improving the consultation process for patients.

CONCLUSIONS

The Canfield Vectra XT 3D system has proven to be remarkably accurate in predicting the volumetric outcomes of breast augmentation surgery, with an accuracy rate exceeding 91.9%. It stands as a valuable tool for surgeons and patients alike, enhancing the preoperative planning process by offering a realistic preview of surgical results. This advancement not only facilitates a deeper understanding and setting of realistic expectations for patients but also strengthens the communication between patients and surgeons, ultimately leading to higher satisfaction rates with the surgical outcomes. It also emphasizes the significance of detailed documentation and consent processes in protecting against legal repercussions.

LEVEL OF EVIDENCE II

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 .

Evaluation of a Structured Light Scanner for 3D Facial Imaging: A Comparative Study with Direct Anthropometry

This study evaluates the accuracy and repeatability of craniofacial measurements with a 3D light scanner, specifically the EINSTAR scanner, in comparison to traditional caliper measurements for facial anthropometry. Eleven volunteers were assessed by two examiners, one experienced and one inexperienced, who performed direct caliper measurements and indirect measurements using the scanner. Results indicated minimal differences between caliper and scanner results, with overall high accuracy and reliability demonstrated by correlation coefficients. Despite the slightly longer scanning time, the benefits of 3D imaging, including detailed surface mapping and virtual modeling, justify its integration into clinical practice, particularly in maxillofacial surgery and craniofacial assessment. Craniofacial measurements obtained with the EINSTAR scanner showed excellent reliability and accuracy, which qualifies this method for clinical and scientific use.

How Camera-to-Subject Distance and Height Affect Breast Measurement and Follow-Up Assessment in Plastic Surgery

BACKGROUND

Due to several factors that affect photograph quality, bias is inevitably present in two-dimensional (2D) breast photography. The principal variables affecting image performance at a fixed focus length are the distance between the camera and the subjects and the photography angles.

OBJECTIVE

This study aimed to investigate the effects of camera-to-subject distances and camera height on breast measurement parameters to understand the trend of breast deformation and provide guidance for the accurate evaluation of planar follow-up.

METHODS

We enlisted 16 volunteers with various breast cup sizes (A-D). Frontal and lateral photos were obtained with a steady focus of 50 mm at distances between 1.10 m and 2.20 m and at heights between 30 cm above the nipple and 30 cm below the nipple at intervals of 10 cm. Two researchers independently evaluated each volunteer's breast aesthetic parameters, including 11 linear parameters, 3 area parameters, and 3 ratio parameters, using Vernier calipers and Photoshop.

RESULTS

The correlation coefficient of the two investigators ranged from 0.922 to 0.999. The results measured by Photoshop were 29.67 ± 5.23% greater than those of the Vernier caliper (p < 0.01). In contrast to ratio parameters, which showed no significant changes in each distance group (p = 1.00), linear parameters and area parameters significantly increased as object distance decreased (p < 0.05). The lower pole of the breast grew wider and flatter and occupied a larger proportion of the breast as height declined.

CONCLUSION

Camera-to-subject distances of 1.5-1.7 m are recommended for stabilized and uniform breast photography. Varying shooting height affects breast distortion. Quantifying the relationship between photographic conditions and breast morphology enables plastic surgeons to conduct more comprehensive and accurate assessments.

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. Bullet point list: 1. The breast morphology will get more distortion with a smaller camera-to-subject distance. 2. Camera-to-subject distances of 1.5~1.7m are recommended for stabilized and uniform breast photography. 3. Height rather than distance affects the breast proportion.

3D Analysis of the Cranial and Facial Shape in Craniosynostosis Patients: A Systematic Review

With increasing interest in 3D photogrammetry, diverse methods have been developed for craniofacial shape analysis in craniosynostosis patients. This review provides an overview of these methods and offers recommendations for future studies. A systematic literature search was used to identify publications on 3D photogrammetry analyses in craniosynostosis patients until August 2023. Inclusion criteria were original research reporting on 3D photogrammetry analyses in patients with craniosynostosis and written in English. Sixty-three publications that had reproducible methods for measuring cranial, forehead, or facial shape were included in the systematic review. Cranial shape changes were commonly assessed using heat maps and curvature analyses. Publications assessing the forehead utilized volumetric measurements, angles, ratios, and mirroring techniques. Mirroring techniques were frequently used to determine facial asymmetry. Although 3D photogrammetry shows promise, methods vary widely between standardized and less conventional measurements. A standardized protocol for the selection and documentation of landmarks, planes, and measurements across the cranium, forehead, and face is essential for consistent clinical and research applications.

"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.

Quantitative Assessment of Periocular Autologous Fat Transfer Survival Using 3D Stereophotogrammetric Imaging

PURPOSE

To assess periocular autologous fat transfer (AFT) survival by assessment of volume change with sequential 3D VECTRA imaging.

OBJECTIVE

Little is known about the patterns of graft survival of AFT in the periorbital region, especially in cases involving prior radiotherapy or trauma. The aim of this pilot study was to characterize fat survival following AFT in patients with a broad range of clinical indications, with and without a history of prior radiotherapy, for both periocular and orbital AFT, and in a subgroup of patients with an anophthalmic socket.

METHOD

A single-institution, prospective cohort study involving 18 applications of AFT for volume augmentation in the periocular and orbital area. All patients had sequential 3D VECTRA photographs following a validated standardized protocol. Patient demographics, including gender, age, ethnicity, underlying diagnosis, and volume of fat injected, were also collected.

RESULTS

In total 13 patients were enrolled, 9 female (69.2%) and 4 male (31.0%). Mean age at the time of surgery was 47.8 years. Patients had volume deficiency secondary to a variety of causes; the most common cause was postenucleation socket syndrome following trauma in 6 patients (46.2%). The mean fat survival volume at the 1-month postoperative point was 70% and 55% by 6 months. AFT conducted with a multiport cannula for fat harvesting use had an initial higher rate of fat reabsorption with ANOVA p = 0.002, however, this was not observed at the later follow-up periods. There was no statistically significant difference in fat survival between abdominal or thigh donor fat sites. There was no statistically significant difference in residual injected volume at the early follow-up period between patients who had prior radiotherapy and those who did not p = 0.8496.

CONCLUSION

AFT is an effective treatment for periorbital volume compromise with an acceptable survival rate in all categories of patients. Complex etiologies such as radiotherapy-related orbital and midface dysgenesis should not be a contraindication for AFT, with no difference in outcomes.

Development and Validation of a Comprehensive Perioral Evaluation Method Using Three-Dimensional Stereophotogrammetry

BACKGROUND

The non-invasive three-dimensional (3D) stereophotogrammetry is widely used in anthropometry for medical purpose. Yet, few studies have assessed its reliability on measuring the perioral region.

OBJECTIVES

This study aimed to provide a standardized 3D anthropometric protocol for the perioral region.

METHODS

38 female and 12 male Asians were recruited (mean age 31.6 ± 9.6 years). Two sets of 3D images using the VECTRA 3D imaging system were acquired for each subject, and two measurement sessions for each image were performed independently by two raters. 25 landmarks were identified, and 28 linear, 2 curvilinear, 9 angular and 4 areal measurements were evaluated for intrarater, interrater, and intramethod reliability.

RESULTS

Our results showed high reliability of 3D imaging-based perioral anthropometry by mean absolute difference (0.57 and 0.57 unit), technical error measurement (0.51 and 0.55 unit), relative error of measurement (2.18% and 2.44%), relative technical error of measurement (2.02% and 2.34%), and intraclass correlation coefficient (0.98 and 0.98) for intrarater 1 and intrarater 2 reliability; respectively 0.78 unit, 0.74 unit, 3.26%, 3.06% and 0.97 for interrater reliability; and respectively 1.01 unit, 0.97 unit, 4.74%, 4.57% and 0.95 for intramethod reliability.

CONCLUSIONS

This standardized protocol utilizing 3D surface imaging technologies are feasible and highly reliable in perioral assessment. It could be further applied for diagnostic purpose, surgical planning and therapeutic effect evaluation in clinical practice in relation to perioral morphologies.

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 evaluation of symmetry in facial palsy reanimation using stereophotogrammetric devices: A series of 15 cases

Facial palsy can severely compromise quality of life, significantly altering the harmony and symmetry of the face, which can be restored by surgical rehabilitation. The aim of the study was the quantification of facial symmetry following facial reanimation. Fifteen consecutive adult patients were surgically treated through triple innervation for reanimation of flaccid unilateral facial paralysis (contralateral facial nerve, masseteric nerve, and hypoglossal nerve) and fascia lata graft for definition of the nasolabial sulcus. In the preoperative stage and at least 11 months after the surgical treatment, three-dimensional facial images were recorded through stereophotogrammetry in a neutral (rest) position, and with Mona Lisa and full-denture (maximum) smiles. Labial commissure inclination relative to the interpupillary axis, and a surface assessment of local facial asymmetry at rest and while smiling were obtained for the upper, middle, and lower facial thirds. The angle between the interpupillary axis and the labial commissure significantly improved in post-surgical acquisitions, regaining symmetry at rest (t-test; p < 0.001). Facial symmetry increased significantly when passing from pre-to postsurgical facial scans, from the lower to the upper facial third, and from the full smile to the rest position (ANOVA; p < 0.001). After treatment, the full smile recovered more symmetry than the other two expressions. In summary, surgical treatment significantly reduced facial asymmetry, but this reduction differed significantly among the various animations and facial thirds. The results of this study confirmed clinical findings of significant static and dynamic improvements in facial symmetry after triple innervation reanimation surgery.

Can smartphones be used for routine dental clinical application? A validation study for using smartphone-generated 3D facial images

OBJECTIVES

To compare the accuracy of smartphone-generated three-dimensional (3D) facial images to that of direct anthropometry (DA) and 3dMD with the aim of assessing the validity and reliability of smartphone-generated 3D facial images for routine clinical applications.

MATERIALS AND METHODS

Twenty-five anthropometric soft-tissue facial landmarks were labelled manually on 22 orthognathic surgery patients (11 males and 11 females; mean age 26.2 ± 5.3 years). For each labelled face, two imaging operations were performed using two different surface imaging systems: 3dMDface and Bellus3D FaceApp. Next, 42 inter-landmark facial measurements amongst the identified facial landmarks were measured directly on each labelled face and also digitally on 3D facial images. The measurements obtained from smartphone-generated 3D facial images (SGI) were statistically compared with those from DA and 3dMD.

RESULTS

SGI had slightly higher measurement values than DA and 3dMD, but there was no statistically significant difference between the mean values of inter-landmark measures across the three methods. Clinically acceptable differences (≤3 mm or ≤5°) were observed for 67 % and 74 % of measurements with good agreement between DA and SGI, and 3dMD and SGI, respectively. An overall small systematic bias of ± 0.2 mm was observed between the three methods. Furthermore, the mean absolute difference between DA and SGI methods was highest for linear (1.41 ± 0.33 mm) as well as angular measurements (3.07 ± 0.73°).

CONCLUSIONS

SGI demonstrated fair trueness compared to DA and 3dMD. The central region and flat areas of the face in SGI are more accurate. Despite this, SGI have limited clinical application, and the panfacial accuracy of the SGI would be more desirable from a clinical application standpoint.

CLINICAL SIGNIFICANCE

The usage of SGI in clinical practice for region-specific macro-proportional facial assessment involving central and flat regions of the face or for patient education purposes, which does not require accuracy within 3 mm and 5° can be considered.

Evaluation of the Portable Next-Generation VECTRA H2 3D Imaging System for Measuring Upper Eyelid Area and Volume

BACKGROUND

Although a portable 3-dimensional (3D) imaging system has been used for periocular measurement analysis, this system has yet to be tested and validated for periocular area and volume measurements.

OBJECTIVES

The aim of this study was to define the upper eyelid and upper eyelid fold region through a modified landmark strategy and validate a portable 3D imaging system for area and volume measurements in this periocular region.

METHODS

Eighty-one healthy adult Caucasians underwent 3D facial imaging with the VECTRA M3 (static) and VECTRA H2 (portable) 3D imaging systems (Canfield Scientific, Inc., Parsippany, NJ). Subsequently, the upper eyelid and upper eyelid fold regions were selected according to a modified landmark localization strategy. Direct measurements of area and volume were performed to assess intrarater, interrater, intramethod, and intermethod reliability, and to compare the agreement between the 2 devices.

RESULTS

The VECTRA M3 and H2 showed high reliability on upper eyelid area measurements. Excellent intra-, inter-, and intramethod reliability agreements were observed in intraclass correlation coefficient; very good agreement in intrarater reliability was observed in the relative error of measurement (REM) and relative technical error of measurement (rTEM); and good inter- and intramethod reliability were observed in the REM and rTEM. For area measurement of the upper eyelid fold, the intrarater, interrater, and intramethod reliability of the M3 was lower than that of the H2. Both systems had poor intrarater, interrater, and intramethod reliability for volume measurements in the upper eyelid and upper eyelid fold region.

CONCLUSIONS

This new portable 3D imaging system achieved excellent or very good reliability values for standardized direct measurements of the upper eyelid and upper eyelid fold region, although volume measurements seem less reliable.

What is the impact of miniscrew-assisted rapid palatal expansion on the midfacial soft tissues? A prospective three-dimensional stereophotogrammetry study

OBJECTIVES

To evaluate the midfacial soft tissue changes of the face in patients treated with miniscrew-assisted rapid palatal expansion (MARPE).

MATERIALS AND METHODS

3D facial images and intra-oral scans (IOS) were obtained before expansion (T0), immediately after completion of expansion (T1), and 1 year after expansion (T2). The 3D images were superimposed and two 3D distance maps were generated to measure the midfacial soft tissue changes: immediate effects between timepoints T0 and T1 and overall effects between T0 and T2. Changes of the alar width were also measured and dental expansion was measured as the interpremolar width (IPW) on IOS.

RESULTS

Twenty-nine patients (22 women, 7 men, mean age 25.9 years) were enrolled. The soft tissue in the regions of the nose, left of philtrum, right of philtrum, and upper lip tubercle demonstrated a statistically significant anterior movement of 0.30 mm, 0.93 mm, 0.74 mm, and 0.81 mm, respectively (p < 0.01) immediately after expansion (T0-T1). These changes persisted as an overall effect (T0-T2). The alar width initially increased by 1.59 mm, and then decreased by 0.08 mm after 1 year, but this effect was not significant. The IPW increased by 4.58 mm and remained stable 1 year later. There was no significant correlation between the increase in IPW and alar width (r = 0.35, p = 0.06).

CONCLUSIONS

Our findings indicate that MARPE results in significant but small changes of the soft tissue in the peri-oral and nasal regions. However, the clinical importance of these findings is limited.

CLINICAL RELEVANCE

MARPE is an effective treatment modality to expand the maxilla, incurring only minimal and clinically insignificant changes to the midfacial soft tissues.

Three-dimensional Evaluation of Results After Dual-Plane Breast Augmentation with and Without Internal Suture Mastopexy

BACKGROUND

In patients with breast atrophy and ptosis, it is necessary to correct both problems simultaneously. This study aimed to analyze breast morphological changes with a three-dimensional (3D) scanning technique to demonstrate the improvement effect of dual-plane breast augmentation combined with internal suture mastopexy.

METHODS

3D breast surface scans were performed preoperatively and postoperatively in 24 patients (n = 35 breasts) undergoing internal suture mastopexy combined with prosthetic augmentation through the periareolar approach and 24 patients (48 breasts) undergoing simple dual-plane breast augmentation. Changes in linear distance, breast volume and volume distribution, breast projection, and nipple position were analyzed to assess the breast morphology.

RESULTS

Compared with simple breast augmentation, augmentation combined with internal suture mastopexy was associated with a higher upper pole volume increase and greater medial and upward nipple displacement. After the surgery, the upper pole volume increased by an average of 10.6% in combined augmentation group and decreased by an average of 2.2% in the simple breast augmentation group. The measured breast projections were 24.8 ± 2.2% lower than expected in the combined group and 23.1 ± 4.1% lower than expected in the simple group, based on implant parameters recorded by the manufacturer. The nipple moved 0.2 ± 0.5 cm laterally, 1.6 ± 0.6 cm upward, and 2.8 ± 0.7 cm anteriorly in the combined group and 0.9 ± 0.5 cm laterally, 0.7 ± 0.6 cm upward, and 3.0 ± 0.6 cm anteriorly in the simple group.

CONCLUSIONS

Dual-plane breast augmentation in addition to internal suture mastopexy appears to reposition breast tissue from the lower pole to fill in the deficient upper breast, pull the nipple medially and superiorly, and ultimately correct mild to moderate breast ptosis.

LEVEL OF EVIDENCE III

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 .

The Clinical Efficacy Evaluation of Thigh Liposuction Based on 3-Dimensional Digital Technology: A Quantitative Study

BACKGROUND

There is a lack of convenient and accurate objective methods to evaluate the clinical efficacy of thigh liposuction.

METHODS

This retrospective study involved the 3-dimensional images of 19 patients who underwent bilateral thigh liposuction. Data such as volume change and volume change rate before and after surgery, circumference change, and circumference change rate of 3 planes (upper, middle, and lower) were analyzed. The correlation between body mass index and volume change rate and between preoperative circumference and circumference change rate of different planes were determined.

RESULTS

There were significant differences between the preoperative and postoperative volume and circumference of 3 planes of 19 patients (38 thighs). The rate of change in total volume (16.90 ± 5.55%) correlated with the circumference change rate at the top of the thigh. There was also a linear relationship between body mass index and volume change rate, but not between preoperative circumference and circumference change rate.

CONCLUSIONS

Three-dimensional imaging technology can accurately quantify the volume and circumference change of the thigh to objectively evaluate the clinical efficacy of thigh liposuction.

Three-dimensional soft tissue landmark detection with marching cube algorithm

Current method of analyzing three-dimensional soft tissue data, especially in the frontal view, is subjective and has poor reliability. To overcome this limitation, the present study aimed to introduce a new method of analyzing soft tissue data reconstructed by marching cube algorithm (Program S) and compare it with a commercially available program (Program A). Cone-beam computed tomography images of 42 patients were included. Two orthodontists digitized six landmarks (pronasale, columella, upper and lower lip, right and left cheek) twice using both programs in two-week intervals, and the reliability was compared. Furthermore, computer-calculated point (CC point) was developed to evaluate whether human error could be reduced. The results showed that the intra- and inter-examiner reliability of Program S (99.7-100% and 99.9-100%, respectively) were higher than that of Program A (64.0-99.9% and 76.1-99.9%, respectively). Moreover, the inter-examiner difference of coordinate values and distances for all six landmarks in Program S was lower than Program A. Lastly, CC point was provided as a consistent single point. Therefore, it was validated that this new methodology can increase the intra- and inter-examiner reliability of soft tissue landmark digitation and CC point can be used as a landmark to reduce human error.

Breast Morphological Comparison Between Anatomic and Round Implant Augmentation: A Prospective Study

BACKGROUND

The choice of implant shape (anatomic or round) is one of the most critical issues for breast augmentation. Determining whether there are differences in the postoperative breast morphology of the 2 implants is pivotal for surgical planning. This issue has been controversial and lacking in evidence. The aim of this study was to provide reference for implant selection by comparing breast morphology after dual-plane augmentation with anatomic and round implants using 3-dimensional scanning technology.

METHODS

Patients with implant volume less than 300 mL who underwent transaxillary dual-plane augmentation were included in this study and were grouped according to implant shape. Three-dimensional scans were performed preoperatively and 6 months postoperatively. Postoperative breast height (BH), breast width (BW), BH of upper pole (BHUP), BH of lower pole (BHLP), breast projection (BP), BP of upper pole (BPUP), and BP of lower pole (BPLP) were measured separately, resulting in corresponding ratios (BH/BW, BHUP/BHLP, BP/BH, BPUP/BPLP). Breast volume, and the volumes of each pole (breast volume of upper pole [BVUP], breast volume of lower pole [BVLP]) and its ratio (BVUP/BVLP) were calculated. Correlation and regression analysis on the influencing factors of breast volume were performed.

RESULTS

Thirty patients with anatomic implants and 26 with round implants were enrolled in this study. The mean volumes of anatomic and round implants were 260.5 ± 26.7 and 267.9 ± 21.7 mL (P = 0.192). The ratios of BH/BW in the 2 groups were 1.39 ± 0.12 and 1.37 ± 0.19, respectively (P = 0.582). The BHUP/BHLP values of 2 groups were 1.35 ± 0.22 and 1.41 ± 0.25 (P = 0.160). Two sets of BPUP/BPLP were 0.68 ± 0.19 and 0.73 ± 0.17 (P = 0.133). The ratios of BP/BH in the 2 groups were 0.39 ± 0.08 and 0.39 ± 0.06 (P = 0.830). The BVUP/BVLP ratios for both groups were 0.75 ± 0.11 and 0.77 ± 0.12 (P = 0.287). There was a volume loss rate of 13.3% ± 3.9% and 13.9% ± 5% (P = 0.489). The postoperative volume showed a positive correlation with both the preoperative volume and the implant volume.

CONCLUSIONS

For patients with breast dysplasia undergoing transaxillary dual-plane augmentation with anatomic or round implants less than 300 mL, the difference in postoperative breast morphology is not obvious. Using these 2 shapes of implants results in a similar degree of volume loss.

Digital pair-matching of iliac bones: pilot study on a three-dimensional approach with models acquired through stereophotogrammetry

Three-dimensional (3D) pair-matching has brought about an innovative approach for the analysis of commingled skeletal remains, and it has been tested on bone models acquired through CT and laser scans. Here, 3D models of 40 innominate bones (20 left and 20 right) of 20 documented male individuals from a cemeterial skeletal collection were acquired through a stereophotogrammetric device (VECTRA M3, Canfield Scientific, Inc.). The ventral iliac surface was chosen as the anatomical region of interest (ROI) for the analysis. Each left ROI was mirrored and superimposed on the matching right ROI (contralateral element from the same individual) and mismatching ROIs (contralateral elements from different individuals). The point-to-point distance between models was calculated through the Vectra Analysis Module (VAM) software and the root mean square (RMS) point-to-point distance value was used to evaluate the sorting performance of the method, in terms of sensitivity and specificity rates. Differences in RMS between matches and mismatches were investigated through a Student's t test (p < 0.05). The state of preservation of the remains was assessed following an index of anatomical completeness and differences in RMS distances of true matches according to different anatomical completeness were assessed through the Mann-Whitney test (p < 0.05). RMS point-to-point distances of matches and mismatches were significantly different (p < 0.01), being the matches lower than mismatches. The RMS threshold of 2.9 mm identified all the true pairs; the test was 100% sensitive and 51% specific. The RMS of matches with a better state of preservation are significantly lower than the less preserved matches (p < 0.05). In general, a low RMS distance value may indicate a true match, being it to be further verified. The 3D approach for sorting innominate bones provides a valid screening test that could complete subjective and osteometric methods with numerical evidence of the match. Preliminary data suggest a possible relation between RMS distance values and taphonomic condition, which would benefit from further research.

Age-related changes of the periocular morphology: a two- and three-dimensional anthropometry study in Caucasians

PURPOSE

To determine age-and sex-related changes in periocular morphology in Caucasians using a standardized protocol.

METHODS

Healthy Caucasian volunteers aged 18-35 and 60-90 years old were recruited from the Department of Ophthalmology, Faculty of Medicine and University Hospital, Cologne, between October 2018 and May 2020. Volunteers with facial asymmetry, facial deformities, history of facial trauma, facial surgery, botox injection, eyelid ptosis, strabismus, or nystagmus, were excluded. Standardized three-dimensional facial photos of 68 young volunteers and 73 old volunteers were taken in this clinical practice. Position changes of endocanthion, pupil center, and exocanthion were analyzed in different age and gender groups, including palpebral fissure width (PFW): distance between endocanthions (En-En), pupil centers (Pu-Pu), exocanthions (Ex-Ex), endocanthion and nasion (En-Na), pupil center and nasion (Pu-Na), exocanthion and nasion (Ex-Na), endocanthion and pupil center (Pu-En), exocanthion and pupil center (Pu-Ex), and palpebral fissure inclination (PFI); angle of endocanthions to nasion (En-Na-En), pupils to nasion (Pu-Na-Pu), exocanthions to nasion (Ex-Na-Ex); endocanthion inclination (EnI), and exocanthion inclination (ExI).

RESULTS

PFW, En-En, Ex-Na, Pu-Ex, PFI, ExI, and Ex-Na-Ex were significantly different between the young and old groups (p ≤ 0.004). There were sex-related differences in PFW, Ex-Ex, En-Na, Pu-Na, Ex-Na, Pu-En, PFI, and EnI between both groups (p ≤ 0.041).

CONCLUSION

The position change of the pupil is minimal relative to age; it is preferred to establish the reference plane to describe periocular changes. The endocanthion tends to move temporally and inferiorly, while the exocanthion tends to shift nasally and inferiorly with age.

Objective Assessment of the Long-Term Volumizing Action of a Polycaprolactone-Based Filler

Background

The polycaprolactone-based filler, (PCL-1, Ellansé-S), forms part of the recently growing portfolio of biodegradable collagen-stimulating fillers. It is comprised of a suspension of 25-50 micron diameter microspheres of polycaprolactone (PCL) (30%) in a carboxymethyl cellulose (CMC) gel carrier (70%) and has gained popularity due to its long-term volumizing action.

Objective

This study outlines a retrospective case series of nine patients injected with the PCL-1, for volume augmentation in the mid-face. Objective volume calculations were performed with the Canfield Vectra 3D Imaging System at two time points post-implantation, with the objective of determining the longevity of the volumizing effect of the bio-stimulating substance.

Results

A clear increase in volume, between 50-150%, was found in all of the patients at two years, over and above the volume initially injected. All the patients were satisfied with the longevity of the results.

Discussion

The PCL-based filler is believed to afford immediate volume restoration due to the CMC gel component and a long-term action due to neo-collagenesis, induced by the PCL microspheres. The CMC gel is known to dissipate within 6-8 weeks, only to be replaced by new collagen induced by the PCL particles. Thus soft-tissue formation induced by the PCL particles, ultimately leads to a sustained volumizing effect.

Conclusion

The PCL-based filler is shown to have a sustained volumizing effects of at least 2 years duration with clear evidence of increase in volume over and above the volume injected, in all of the cases studied. This is indicative of significant neo-collagenesis induced by the PCL microspheres.

Recent Advanced Diagnostic Aids in Orthodontics

Everyone aspires to have a youthful appearance, complete with a beaming grin. By treating skeletal and dental malocclusions that interfere with facial aesthetics, orthodontics helps patients attain a beautiful face and a smile they will be proud of. The diagnosis of the underlying illness or condition serves as the basis for all medical, dental, and surgical operations. Dental professionals all across the world have reaped the benefits of a major scientific advance in recent years. Many measurements may now be seen and quantified more easily using computer-assisted cephalometry. The accuracy and high quality of all dental materials have been enhanced thanks to computer-aided design and computer-aided manufacture. There have been several developments in the realm of orthodontics. The growing use of technology in recent years has transformed every sector, including medicine and dentistry. From Angle's time to today's nanorobotic age, orthodontic ideas, biomaterials, and technology have evolved greatly. It has been extensively utilized for diagnosis, treatment planning, three-dimensional printing, appliance systems, digital storage, integration, and data retrieval. The technology used in orthodontics is always getting better, and this article aims to give an overview of the most recent changes.

Present and future of extraoral maxillofacial prosthodontics: Cancer rehabilitation

Historically, facial prosthetics have successfully rehabilitated individuals with acquired or congenital anatomical deficiencies of the face. This history includes extensive efforts in research and development to explore best practices in materials, methods, and artisanal techniques. Presently, extraoral maxillofacial rehabilitation is managed by a multiprofessional team that has evolved with a broadened scope of knowledge, skills, and responsibility. This includes the mandatory integration of different professional specialists to cover the bio-psycho-social needs of the patient, systemic health and pathology surveillance, and advanced restorative techniques, which may include 3D technologies. In addition, recent digital workflows allow us to optimize this multidisciplinary integration and reduce the active time of both patients and clinicians, as well as improve the cost-efficiency of the care system, promoting its access to both patients and health systems. This paper discusses factors that affect extraoral maxillofacial rehabilitation's present and future opportunities from teamwork consolidation, techniques utilizing technology, and health systems opportunities.

A Narrative Review on Non-Invasive Diagnostic Tools for the Analysis of Dental Arches in Orofacial Cleft Patients

BACKGROUND

It is necessary to analyze and monitor the facial growth of orofacial cleft patients. The documentation should therefore begin before and after primary surgeries. Technological evolution has transformed plaster models into 3D images through scanners that allow rational storage, manipulation, and rotation without the possibility of breakage or damage. Based on this fact, this narrative review aims to provide a feature on the three-dimensional tools available for the assessment of dental arches in children with orofacial cleft and mixed dentition.

MATERIAL AND METHODS

Three databases were chosen (PubMed, ScienceDirect, and Scopus) and keywords were used to select papers.

RESULTS

During the database screening, 292 potentially relevant papers were found. After removing duplicates, titles, and abstracts, 32 papers presented qualifications for analysis. Through evaluating each document by reading it one by one, 24 papers fulfilled the eligibility criteria.

CONCLUSIONS

It was concluded that digital tools-i.e., benchtop scanners which evaluate the dental arches of children with cleft lip, palate, and mixed dentition-are reproducible and reliable, without the use of ionizing radiation, allow storage, manipulation with sustainability, and help preserve the environment.

Validation of Vectra 3D Imaging Systems: A Review

Aim: Three-dimensional facial imaging systems are a useful tool that is gradually replacing two-dimensional imaging and traditional anthropometry with calipers. In this varied and growing landscape of new devices, Canfield (Canfield Scientific, Parsippany, NJ, USA) has proposed a series of static and portable 3D imaging systems. The aim of this systematic review was to evaluate the current literature regarding the validation of Canfield’s Vectra imaging systems. Materials and Methods: A search strategy was developed on electronic databases including PubMed, Web of Science and Scopus by using specific keywords. After the study selection phase, a total of 10 articles were included in the present review. Results: A total of 10 articles were finally included in the present review. For six articles, we conducted a validation of the Vectra static devices, focusing especially on the Vectra M5, Vectra M3 and Vectra XT. For four articles, we validated the Vectra H1 portable system. Conclusions: All of the reviewed articles concluded that Canfield’s Vectra 3D imaging systems are capable of capturing accurate and reproducible stereophotogrammetric images. Minor errors were reported, particularly in the acquisition of the perioral region, but all the evaluated devices are considered to be valid and accurate tools for clinicians.

Evaluating the accuracy of three-dimensional surface-imaging for circumference analysis of the thigh

BACKGROUND

Three-dimensional (3D) surface-imaging is an increasingly popular and useful tool in surgical planning and evaluation. These systems are used for anthropometric measurements of the face, breast and upper extremity. Its accuracy has, however, not yet been evaluated for the thigh. This could prove useful in the evaluation of autologous breast reconstructions using fasciocutaneous tissue of the thigh, such as the profunda artery perforator (PAP) flap.

METHODS

Thirty-five patients who underwent PAP flap surgery and 35 healthy controls were included. Thigh circumferences were measured using a flexible measuring tape at pre-defined levels. 3D images of the thigh were taken with the Canfield Vectra XT and fused to create 3D reconstructions. 3D circumferences were measured using the Vectra Analysis Module. Measuring tape and 3D circumferences were compared for mutual agreement.

RESULTS

Thigh circumference measurements by measuring tape correlated excellently with 3D measurements (r = 0.999). Bland-Altman plots demonstrated good agreement with a mean difference of -1.2 mm between the measuring tape and 3D measurements. The mean relative difference of both methods was -0.24%. Paired t-tests showed no significant statistical differences between the measuring tape and 3D circumference measurements in legs that underwent PAP flap surgery and without.

CONCLUSIONS

Flexible measuring tape and 3D circumference measurements of the thigh show excellent correlation. Three-dimensional surface imaging can thus be used to measure thigh circumferences in both patients with and without prior surgery of the thigh.

Effects of Artificial Extraoral Markers on Accuracy of Three-Dimensional Dentofacial Image Integration: Smartphone Face Scan versus Stereophotogrammetry

Recently, three-dimensional (3D) facial scanning has been gaining popularity in personalized dentistry. Integration of the digital dental model into the 3D facial image allows for a treatment plan to be made in accordance with the patients’ individual needs. The aim of this study was to evaluate the effects of extraoral markers on the accuracy of digital dentofacial integrations. Facial models were generated using smartphone and stereophotogrammetry. Dental models were generated with and without extraoral markers and were registered to the facial models by matching the teeth or markers (n = 10 in each condition; total = 40). Accuracy of the image integration was measured in terms of general 3D position, occlusal plane, and dental midline deviations. The Mann−Whitney U test and two-way analysis of variance were used to compare results among face-scanning systems and matching methods (α = 0.05). As result, the accuracy of dentofacial registration was significantly affected by the use of artificial markers and different face-scanning systems (p < 0.001). The deviations were smallest in stereophotogrammetry with the marker-based matching and highest in smartphone face scans with the tooth-based matching. In comparison between the two face-scanning systems, the stereophotogrammetry generally produced smaller discrepancies than smartphones.

The Vectra M3 3-dimensional digital stereophotogrammetry system: A reliable technique for detecting chin asymmetry

Purpose

The aim of this study was to evaluate the reliability of the Vectra M3 (3D Imaging System; Canfield Scientific, Parsippany, NJ, USA) in detecting chin asymmetry, and to assess whether the automatic markerless tracking function is reliable compared to manually plotting landmarks.

Materials and Methods

Twenty subjects (18 females and 2 males) with a mean age of 42.5±10.5 years were included. Three-dimensional image acquisition was carried out on all subjects with simulated chin deviation in 4 stages (1-4 mm). The images were analyzed by 2 independent observers through manually plotting landmarks and by Vectra software auto-tracking mode. Repeated-measures analysis of variance and the Tukey post-hoc test were performed to evaluate the differences in mean measurements between the 2 operators and the software for measuring chin deviation in 4 stages. The intraclass correlation coefficient (ICC) was calculated to estimate the intra- and inter-examiner reliability.

Results

No significant difference was found between the accuracy of manually plotting landmarks between observers 1 and 2 and the auto-tracking mode (P=0.783 and P=0.999, respectively). The mean difference in detecting the degree of deviation according to the stage was <0.5 mm for all landmarks.

Conclusion

The auto-tracking mode could be considered as reliable as manually plotted landmarks in detecting small chin deviations with the Vectra® M3. The effect on the soft tissue when constructing a known dental movement yielded a small overestimation of the soft tissue movement compared to the dental movement (mean value<0.5 mm), which can be considered clinically non-significant.

A Longitudinal 3D Investigation on Facial Similarity among Two Monozygotic Twins in Their First Childhood: An Application of the 3D-3D Facial Superimposition Technique

Children affected by orofacial disorders mix functional alterations with morphological problems, and suitable techniques should be devised for their analysis. Stereophotogrammetry and 3D-3D facial superimposition have already proven to reliably assess morphological differences even between twin siblings, separating the effect of genetic and environmental factors. However, little information is available about twin babies. We longitudinally analyzed a couple of healthy monozygotic twin sisters aged 6 months to 5 years (height time points). The entire 3D facial models of the two sisters were registered according to the least point-to-point distance, and the relevant RMS (root mean square) distance between the facial models was calculated at each time and compared with reference data recorded from adult twins (Mann-Whitney test, p < 0.05). RMS values in the twin sisters were on average 1.18 ± 0.21 mm, and 1.86 ± 0.53 mm in adults, with a significant difference (p < 0.01). Results showed that twins are more similar in early childhood when environmental factors are supposed to have not influenced facial morphology sufficiently. Additionally, the technique seems adequate to detect even small differences: the faces of the twin sisters were not fully identical. 3D-3D facial superimposition techniques can objectively quantify facial dissimilarity even in monozygotic twins. The method may be applied to the faces of twins discordant for some orofacial and maxillofacial pathology and potentially separate genetic and environmental factors.

Three-Dimensional Quantification of Facial Asymmetry in Children with Positional Cranial Deformity

BACKGROUND

The extent of facial involvement in positional plagiocephaly is only little investigated so far. Investigation methods that take into account the challenging anatomical conditions and growth of infants' faces are desirable. In this study, the authors established a new three-dimensional photogrammetry quantification method evaluating pretherapeutic and posttherapeutic facial asymmetry in positional plagiocephaly. Furthermore, a facial asymmetry index was established and evaluated.

METHODS

Three-dimensional photographs of 100 children undergoing treatment with head orthoses were analyzed by constructing a standardized interindividual coordinate system. Defining landmarks, section planes, and point coordinates with a computer-aided design software, both sides of the faces were compared. Facial asymmetry was quantified by measuring differences between left and right sides and pretherapeutic and posttherapeutic changes in each patient. The facial asymmetry index was calculated by putting the absolute differences in relation with the coordinates of the nonaffected side.

RESULTS

Present results indicate that positional plagiocephaly results in a distinct facial asymmetry (range, -3.8 to 9.6 mm) in nearly all spatial directions and facial regions. Helmet therapy led to a significant reduction (p < 0.05) of intraindividual facial asymmetry (median change in facial asymmetry index, -1.9 to 3.1 percent). However, no correlation of the Cranial Vault Asymmetry Index and facial asymmetry (Spearman rank correlation coefficient, ρ = -0.09 to 0.47) has been seen. According to these results, severe occipital deformation does not necessarily provoke distinct facial asymmetry.

CONCLUSIONS

Present three-dimensional photogrammetry method allows the longitudinal quantification of facial involvement in positional plagiocephaly. Asymmetry has been determined in all facial regions. The facial asymmetry decreased through helmet therapy but was not eliminated completely.

Vectra 3D Simulation in Lower Eyelid Blepharoplasty: How Accurate is it?

BACKGROUND

Estimating the volume of fat to be resected during lower lid blepharoplasty can be challenging. While the excess fat is clearly visible in the upright position, it retracts into the orbital cavity when the patient is in decubitus. Several tools have been developed to predict the volume required for adequate outcomes and to reduce the risk of complications. Among these, 3D photography, in addition to being noninvasive, radiation-free, portable and relatively inexpensive, can be used to make simulations.

OBJECTIVE

To assess the level of agreement between Vectra H1 camera simulations and the outcome of lower eyelid blepharoplasties with volume removal based on these simulations.

METHODS

Preoperatively, a 3D camera and simulation software (Vectra H1, Canfield Imaging Systems) was used to estimate the fat pad volume to be resected from the lower eyelids in a sample of 35 patients (female n = 34) aged 55 years on average. Following the procedure, the patients were photographed at 1, 3 and 6 months and the outcome was compared to the simulation.

RESULTS

The agreement between the simulated volume and the intraoperative volume was high. While the difference between the postoperative volume and the simulated volume decreased over time, at 6 months the actual volume was still 0.30 mL (right eye) and 0.24 mL (left eye) larger than the simulated volume.

CONCLUSIONS

A systematic and significant difference was found between the simulation volume and the postoperative volume. The low level of agreement observed suggests that the accuracy of the tested software is insufficient for reliable simulations.

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 .

New diagnostic and imaging technologies in dermatology

INTRODUCTION

Diagnosis of dermatological disorders is primarily based on clinical examination in combination with histopathology. However, clinical findings alone may not be sufficient for accurate diagnosis and cutaneous biopsies are being associated with morbidity.

OBJECTIVE

The objective of this article is to review the newer technologies along with their applications, limitation and future prospectus.

METHODOLOGY

Comprehensive literature search was performed using electronic online databases "PubMed" and "Google Scholar". Articles published in English language were considered for the review.

RESULTS

In order to improve and/or widen the armamentarium in dermatologic disease diagnosis and therapy, newer emerging technologies are being made available which aid in diagnosis and management. New emerging technologies include confocal microscopy, digital photographic imaging, optical coherence tomography, high frequency ultrasonography, and artificial intelligence. There have been advancements in the dermoscopes.

CONCLUSION

Significant progress is seen in the diagnostic methods and imaging technologies in dermatology, each having its advantages and limitations. Artificial intelligence/machine-based learning software may have a great scope to influence the dermatological practice.

Digital Leg Volume Quantification: Precision Assessment of a Novel Workflow Based on Single Capture Three-dimensional Whole-Body Surface Imaging

Whole-body three-dimensional surface imaging (3DSI) offers the ability to monitor morphologic changes in multiple areas without the need to individually scan every anatomical region of interest. One area of application is the digital quantification of leg volume. Certain types of morphology do not permit complete circumferential scan of the leg surface. A workflow capable of precisely estimating the missing data is therefore required. We thus aimed to describe and apply a novel workflow to collect bilateral leg volume measurements from whole-body 3D surface scans regardless of leg morphology and to assess workflow precision. For each study participant, whole-body 3DSI was conducted twice successively in a single session with subject repositioning between scans. Paired samples of bilateral leg volume were calculated from the 3D surface data, with workflow variations for complete and limited leg surface visibility. Workflow precision was assessed by calculating the relative percent differences between repeated leg volumes. A total of 82 subjects were included in this study. The mean relative differences between paired left and right leg volumes were 0.73 ± 0.62% and 0.82 ± 0.65%. The workflow variations for completely and partially visible leg surfaces yielded similarly low values. The workflow examined in this study provides a precise method to digitally monitor leg volume regardless of leg morphology. It could aid in objectively comparing medical treatment options of the leg in a clinical setting. Whole-body scans acquired using the described 3DSI routine may allow simultaneous assessment of other changes in body morphology after further validation.

Facial and Eyelid Changes in Thyroid Eye Disease Are Reversed by Teprotumumab

Thyroid eye disease (TED) causes orbital soft-tissue expansion. Recent studies have suggested that brow and temple changes may also occur. Teprotumumab, a monoclonal antibody to the insulin-like growth factor 1 receptor reduces soft-tissue swelling in TED. In this study, we quantified the changes to pan facial soft-tissue volumes and eyelid position, following treatment with teprotumumab.

Assessment of the Orbital and Auricular Asymmetry in Italian and Sudanese Children: A Three-Dimensional Study

The evaluation of the symmetry of orbital and ear soft tissues is important for aesthetic and reconstructive surgery. However, little information is available for these facial regions, especially in children. We analyzed the orbital and auricular symmetry in 418 Italian and 206 Sudanese subadult males divided into three age groups (8–11, 12–15, and 16–19 years old). Orbital and auricular height and width were measured for calculating fluctuating and directional asymmetry indices. Differences in asymmetry indices according to ethnicity and age group were assessed through the two-way ANOVA test (p < 0.01), while differences in the prevalence of right or left asymmetry according to ethnicity were assessed through the chi-square test. On average, directional asymmetry indices ranged from −2.1% to 1.1%, while fluctuating asymmetry indices ranged between 2.9% and 5.4%, corresponding to a small effect size and to 1.06–2.34 mm actual dimensions. Sudanese subjects showed a greater asymmetry for all the indices except for the fluctuating asymmetry of orbital height (p < 0.01). The directional asymmetry of auricular width increased with age. A prevalent right-side asymmetry was found for all the orbital indices (p < 0.001) in both populations, although significantly more prevalent in Sudanese individuals (over 83% for both measures), while auricular measures showed a prevalent left asymmetry exclusively in the Sudanese but with lower percentages. Aside from the limited effect size, the results proved the ethnic variability of asymmetry of orbital and auricle regions in children and suggest the need to collect more population data.

Suggested methodology for longitudinal evaluation of nevi based on clinical images

BACKGROUND

Melanoma screening includes the assessment of changes in melanocytic lesions using images. However, previous studies of normal nevus temporal changes showed variable results and the optimal method for evaluating these changes remains unclear. Our aim was to evaluate the reproducibility of (a) nevus count done at a single time point (method I) versus two time points (method II); and (b) manual and automated nevus diameter measurements.

MATERIALS AND METHODS

In a first experiment, participants used either a single time point or a two time point annotation method to evaluate the total number and size of nevi on the back of an atypical mole syndrome patient. A Monte Carlo simulation was used to calculate the variance observed. In a second experiment, manual measurements of nevi on 2D images were compared to an automated measurement on 3D images. Percent difference in the paired manual and automated measurements was calculated.

RESULTS

Mean nevus count was 137 in method I and 115.5 in method II. The standard deviation was greater in method I (38.80) than in method II (4.65) (p = 0.0025). Manual diameter measurements had intraclass correlation coefficient of 0.88. The observed mean percent difference between manual and automated diameter measurements was 1.5%. Lightly pigmented and laterally located nevi had a higher percent difference.

CONCLUSIONS

Comparison of nevi from two different time points is more consistent than nevus count performed separately at each time point. In addition, except for selected cases, automated measurements of nevus diameter on 3D images can be used as a time-saving reproducible substitute for manual measurement on 2D images.

Reliability of Stereophotogrammetry for Area Measurement in the Periocular Region

Three-dimensional (3D) stereophotography area measurements are essential for describing morphology in the periocular region. However, its reliability has not yet been sufficiently validated. The objective of this study was to evaluate the reliability of 3D stereophotogrammetric area measurements in the periocular region. Forty healthy volunteers had five flat paper objects placed at each of the seven periocular positions including the endocanthion and the upper medial, upper middle, upper lateral, lower medial, lower middle, and the lower lateral eyelid. Two series of photographic images were captured twice by the same investigator. Each image of the first series was measured twice by the same rater, while images of both series were measured once by a second rater. Differences between these measurements were calculated, and the intrarater, interrater, and intramethod reliability was evaluated for intraclass correlation coefficients (ICCs), mean absolute differences (MADs), technical errors of measurements (TEMs), relative errors of measurements (REMs), and relative TEM (rTEM). Our results showed that 21.2% of all ICCs were considered as excellent, 45.5% were good, 27.3% were moderate, and 6.1% were poor. The interrater ICC for the endocanthion location was 0.4% on a low level. MAD values for all objects were less than 0.3 mm², all TEM were less than 1 mm², the REM and rTEM were less than 2% for all objects, showing high reliability. 3D stereophotogrammetry is a highly reliable system for periocular area measurements and may be used in the clinical routine for planning oculoplastic surgeries and for evaluating changes in periocular morphology.

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.

Lip Anthropometry of Healthy Turkish Young Adults

ABSTRACT

The lips play an important role in evaluating and recognizing the craniofacial complex and our perception of facial beauty and attractiveness. The aim of this study was to evaluate the anthropometric measurements of the lips of Turkish young adults and to look for sexual dimorphism. Anterior view photographs were taken of 100 females and 100 males who volunteered to participate in the study. Seven landmarks were determined, stomion (st), sublabiale (sl), subnasale (sn), labiale superius (ls), labiale inferius (li), crista philtre (cp), and chelion (ch). Then, using these landmarks, lower lip height (st-sl), upper lip height (sn-st), philtrum length (sn-ls), upper vermilion height (ls-st), lower vermilion height (li-st), cutaneous lower lip height (li-sl), philtrum width (cp-cp), and mouth width (ch-ch) were measured. It was observed that there was a statistical difference between genders in the parameters of st-sl, sn-st, sn-ls, li-sl, and ch-ch (P = 0.001, for these parameters). Besides, using these distances, 6 anthropometric ratios (ls-st/li-st, sn-ls/ls-st, li-sl/li-st, sn-st/st-sl, cp-cp/ch-ch, and ls-li/ch-ch) were calculated. Among the ratios investigated, sn-ls/ls-st, li-sl/li-st, and cp-cp/ch-ch were statistically significantly larger in males compared females (P = 0.012, P = 0.002, and P = 0.001, respectively). We believe that the results obtained in this study regarding lip anthropometry will help determine the standard values that can be used for the Turkish population aged 18 to 25.

Improving 3D-3D facial registration methods: potential role of three-dimensional models in personal identification of the living

Personal identification of the living from video surveillance systems usually involves 2D images. However, the potentiality of three-dimensional facial models in gaining personal identification through 3D-3D comparison still needs to be verified. This study aims at testing the reliability of a protocol for 3D-3D registration of facial models, potentially useful for personal identification. Fifty male subjects aged between 18 and 45 years were randomly chosen from a database of 3D facial models acquired through stereophotogrammetry. For each subject, two acquisitions were available; the 3D models of faces were then registered onto other models belonging to the same and different individuals according to the least point-to-point distance on the entire facial surface, for a total of 50 matches and 50 mismatches. RMS value (root mean square) of point-to-point distance between the two models was then calculated through the VAM® software. Intra- and inter-observer errors were assessed through calculation of relative technical error of measurement (rTEM). Possible statistically significant differences between matches and mismatches were assessed through Mann–Whitney test (p < 0.05). Both for intra- and inter-observer repeatability rTEM was between 2.2 and 5.2%. Average RMS point-to-point distance was 0.50 ± 0.28 mm in matches, 2.62 ± 0.56 mm in mismatches (p < 0.01). An RMS threshold of 1.50 mm could distinguish matches and mismatches in 100% of cases. This study provides an improvement to existing 3D-3D superimposition methods and confirms the great advantages which may derive to personal identification of the living from 3D facial analysis.

Soft Tissue Changes After Clockwise Rotation of Maxillo-Mandibular Complex in Class III Patients: Three-Dimensional Stereophotogrammetric Evaluation

OBJECTIVES

To evaluate the linear, angular, and volumetric changes of soft tissue after clockwise repositioning of the maxillo-mandibular complex in skeletal class III patients using three-dimensional (3D) stereophotogrammetry and to determine the correlation between changes in the skeletal and soft tissue variables.

METHODS

This study included 18 skeletal class III patients who underwent two-jaw surgery; superior impaction and clockwise rotational movement of the maxilla with the rotation center at upper incisors, and setback of the mandible. Lateral cephalograms and 3D photographs taken before and 6 months after surgery were compared.

RESULTS

After maxillary impaction of anteriorly 1.7 mm and posteriorly 3.1 mm, and mandibular setback of 8.7 mm, the volume of lower lip and chin region decreased significantly by 33.6 cm3 (13% net change, P < 0.001), while paranasal and upper lip region volume increased by 3.2 cm3 (2%) and 7.2 cm3 (4%), respectively.

CONCLUSION

The clockwise rotation of maxillo-mandibular complex in class III patients significantly reduced lower lip and chin volume with minimal increase in paranasal and upper lip volumes. 3D stereophotogrammetry can provide quantitative evaluation of facial soft tissue volumetric changes.

Craniofacial Anthropometry of Healthy Turkish Young Adults: Analysis of Head and Face

ABSTRACT

The aim of this study was to evaluate the craniofacial anthropometric measurements of Turkish young adults between the ages of 18 and 25. Anterior view and side profile photographs were taken of 100 females and 100 males who volunteered to participate in the study and had no craniofacial anomalies, history of facial trauma, or history of orofacial surgery. Thirteen landmarks on the face and head were chosen, and these landmarks were identified on the photographs. Then, using these landmarks, a total of 19 distance measurements were made, 16 from the anterior view, and 3 from the side profile. There were statistically significant differences between the sexes in 13 parameters: 2 parameters (t-n and ft-ft) being higher in females and 11 parameters (v-n, v-t, t-gn, sn-gn, n-gn, st-gn, sl-gn, fz-fz, z-z, tr-tr and go-go) being higher in males. Also, 7 facial anthropometric ratios were calculated. There were statistically significant differences between the genders in all ratios. The literature reveals that craniofacial anthropometric measurements have been performed on many different populations and that there are numerous differences between the results of the studies conducted. We are of the opinion that the results obtained in this present study will contribute to the literature by helping to determine the standard values for the Turkish population between the ages of 18 and 25, which can be used in diagnosis, treatment and postoperative evaluation in areas such as forensic science, orthodontics, clinical genetics, maxillofacial surgery, and plastic surgery.

Underwater photogrammetry for close-range 3D imaging of dry-sensitive objects: The case study of cephalopod beaks

Technical advances in 3D imaging have contributed to quantifying and understanding biological variability and complexity. However, small, dry-sensitive objects are not easy to reconstruct using common and easily available techniques such as photogrammetry, surface scanning, or micro-CT scanning. Here, we use cephalopod beaks as an example as their size, thickness, transparency, and dry-sensitive nature make them particularly challenging. We developed a new, underwater, photogrammetry protocol in order to add these types of biological structures to the panel of photogrammetric possibilities.We used a camera with a macrophotography mode in a waterproof housing fixed in a tank with clear water. The beak was painted and fixed on a colored rotating support. Three angles of view, two acquisitions, and around 300 pictures per specimen were taken in order to reconstruct a full 3D model. These models were compared with others obtained with micro-CT scanning to verify their accuracy.The models can be obtained quickly and cheaply compared with micro-CT scanning and have sufficient precision for quantitative interspecific morphological analyses. Our work shows that underwater photogrammetry is a fast, noninvasive, efficient, and accurate way to reconstruct 3D models of dry-sensitive objects while conserving their shape. While the reconstruction of the shape is accurate, some internal parts cannot be reconstructed with photogrammetry as they are not visible. In contrast, these structures are visible using reconstructions based on micro-CT scanning. The mean difference between both methods is very small (10-5 to 10-4 mm) and is significantly lower than differences between meshes of different individuals.This photogrammetry protocol is portable, easy-to-use, fast, and reproducible. Micro-CT scanning, in contrast, is time-consuming, expensive, and nonportable. This protocol can be applied to reconstruct the 3D shape of many other dry-sensitive objects such as shells of shellfish, cartilage, plants, and other chitinous materials.

Three-Dimensional Facial Anthropometric Analysis With and Without Landmark Labelling: Is There a Real Difference?

INTRODUCTION

The actual role of landmarks labeling before three-dimensional (3D) facial acquisition is still debated. In this study, several measurements were compared among textured labeled (TL), unlabeled (NL), and untextured (NTL) 3D facial models.

MATERIALS AND METHODS

The face of 50 subjects was acquired through stereophotogrammetry. Landmark coordinates were extracted from TL, NL, and NTL facial models, and 33 linear and angular measurements were calculated, together with surface area and volume. Accuracy of measurements among TL, NL, and NTL models was assessed through calculation of relative technical error of measurement (rTEM). The intra- and inter-observer errors for each type of facial model were calculated.

RESULTS

Intra- and inter-observer error of measurements increased passing from textured to NTL and NL 3D models. Average rTEMs between TL models, and NTL and NL models were 4.5 ± 2.6% and 4.7 ± 2.8%, respectively, almost all measurements being classified as "very good" or "good." Only for orbital height and its inclination, mandibular ramus length, nasal convexity, alar slope angle, and facial divergence, rTEM was classified as "moderate" or "poor."

CONCLUSIONS

Accuracy and precision of measurements decrease when landmarks are not previously labeled; attention must be taken when measurements have a low magnitude or involve landmarks requiring palpation.

Three-dimensional changes in the location of soft tissue landmarks following bimaxillary orthognathic surgery

OBJECTIVES

We sought to determine the amount of three-dimensional (3D) movement of soft tissue landmarks in patients who underwent bimaxillary orthognathic surgery.

MATERIALS AND METHODS

We recruited 28 patients (11 women and 17 men), who had received one-piece Le Fort I osteotomy with maxillary advancement and impaction, and bilateral sagittal split ramus osteotomy for mandibular setback. The 3D images were acquired 1-7 days before surgery and at least 6 months after surgery using stereophotogrammetry. We recorded 50 coordinate measurements and correlated the movements between soft and hard tissues. Paired samples t‑test, independent samples t‑test, and Pearson's correlation analysis were used for statistical analysis.

RESULTS

Patients' ages ranged from 17-31 years (mean 20.4 ± 3.0 years). The mean advancement and impaction of the maxilla was 4.7 ± 1.2 and 2.2 ± 1.0 mm, respectively. The mean setback of the mandible was 4.2 ± 1.6 mm. Menton (Me) moved significantly closer to the midsagittal plane, and the bilateral alare (Al) and alar curvature (Ac) moved laterally. In addition, pronasale (Prn), bilateral Al, Ac, subnasale (Sn), subspinale (Ss), labiale superior (Ls), sublabiale (Sl), pogonion (Pog), and Me moved upwards. The bilateral cheek bone (Cbp), Al, Ac, Prn, Sn, Ss, Ls, and stomion (Sto) moved forward. Li, Sl, Pog, and Me moved backward. Interestingly, poor correlation was found between soft tissue landmarks and hard tissue movements.

CONCLUSION

We observed 3D coordinate changes in several soft tissue landmarks in the middle and lower thirds of the face. The results of this study may be useful for estimating postoperative changes in similar patients.

Reproducibility of 3D scanning in the periorbital region

The reproducibility of scanning in the periorbital region with 3D technology to enable objective evaluations of surgical treatment in the periorbital region was assessed. Facial 3D-scans of 15 volunteers were captured at different time points with a handheld Artec Space Spider structured light scanner. Two scans were made with a one minute interval and repeated after 1 year; for both a natural head position and with the head in a fixation-device. On assessing the area between the eyelashes and eyebrows, the medians of the average deviations between the various cross-sections of the one minute interval 3D-scans ranged from 0.17 to 0.21 mm at baseline, and from 0.10 to 0.11 mm when the minute-interval scanning was repeated one year later. The systematic differences when scanning in a natural head position and fixated position were comparable. The reproducibility of the 3D processing was excellent (intraclass correlation coefficient > 0.9). The repeated scanning deviations (baseline versus one year data) were well within the accepted clinical threshold of 1 mm. Scanning with a hand-held 3D-scanning device (Artec Space Spider) is a promising tool to assess changes in the periorbital region following surgical treatment since the median deviations are well below the clinically accepted 1 mm measuring error, for both the natural head and fixated positions.

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.