Measuring Symmetry in Children With Unrepaired Cleft Lip: Defining a Standard for the Three-Dimensional Midfacial Reference Plane

Automatic extraction of facial median sagittal plane for patients with asymmetry based on the EDMA alignment algorithm

BACKGROUND

We aimed to establish a novel method for automatically constructing three-dimensional (3D) median sagittal plane (MSP) for mandibular deviation patients, which can increase the efficiency of aesthetic evaluating treatment progress. We developed a Euclidean weighted Procrustes analysis (EWPA) algorithm for extracting 3D facial MSP based on the Euclidean distance matrix analysis, automatically assigning weight to facial anatomical landmarks.

METHODS

Forty patients with mandibular deviation were recruited, and the Procrustes analysis (PA) algorithm based on the original mirror alignment and EWPA algorithm developed in this study were used to construct the MSP of each facial model of the patient as experimental groups 1 and 2, respectively. The expert-defined regional iterative closest point algorithm was used to construct the MSP as the reference group. The angle errors of the two experimental groups were compared to those of the reference group to evaluate their clinical suitability.

RESULTS

The angle errors of the MSP constructed by the two EWPA and PA algorithms for the 40 patients were 1.39 ± 0.85°, 1.39 ± 0.78°, and 1.91 ± 0.80°, respectively. The two EWPA algorithms performed best in patients with moderate facial asymmetry, and in patients with severe facial asymmetry, the angle error was below 2°, which was a significant improvement over the PA algorithm.

CONCLUSIONS

The clinical application of the EWPA algorithm based on 3D facial morphological analysis for constructing a 3D facial MSP for patients with mandibular deviated facial asymmetry deformity showed a significant improvement over the conventional PA algorithm and achieved the effect of a dental clinical expert-level diagnostic strategy.

3D facial mask for facial asymmetry diagnosis

Objectives

Facial asymmetry is a common problem seen in orthodontic clinics that may affect patient esthetics. In some instances, severe asymmetry that affects patient esthetics may cause psychological issues. An objective method is therefore required to help orthodontists identify asymmetry issues.

Materials and methods

We used three-dimensional (3D) facial images and landmark-based anthropometric analysis to construct a 3D facial mask to evaluate asymmetry. The landmark coordinates were transformed using a symmetric 3D face model to evaluate the efficacy of this method. Patients with facial asymmetry were recruited to conduct mirror and overlap analysis to form color maps, which were used to verify the utility of the novel soft tissue landmark-based method.

Results

The preliminary results demonstrated that the asymmetry evaluation method had a similar response rate compared to diagnosis using mirror and overlap 3D images, and could therefore identify 3D asymmetry problems.

Conclusions

By using 3D facial scans and 3D anthropometric analysis, we developed a preliminary evaluation method that provides objective parameters to clinically evaluate patient facial asymmetry and aid in the diagnosis of asymmetric areas.

Clinical relevance

This study presents a novel facial asymmetry diagnostic method that has the potential to aid clinical decisions during problem identification, treatment planning, and efficacy evaluation.

Synergy between artificial intelligence and precision medicine for computer-assisted oral and maxillofacial surgical planning

OBJECTIVES

The aim of this review was to investigate the application of artificial intelligence (AI) in maxillofacial computer-assisted surgical planning (CASP) workflows with the discussion of limitations and possible future directions.

MATERIALS AND METHODS

An in-depth search of the literature was undertaken to review articles concerned with the application of AI for segmentation, multimodal image registration, virtual surgical planning (VSP), and three-dimensional (3D) printing steps of the maxillofacial CASP workflows.

RESULTS

The existing AI models were trained to address individual steps of CASP, and no single intelligent workflow was found encompassing all steps of the planning process. Segmentation of dentomaxillofacial tissue from computed tomography (CT)/cone-beam CT imaging was the most commonly explored area which could be applicable in a clinical setting. Nevertheless, a lack of generalizability was the main issue, as the majority of models were trained with the data derived from a single device and imaging protocol which might not offer similar performance when considering other devices. In relation to registration, VSP and 3D printing, the presence of inadequate heterogeneous data limits the automatization of these tasks.

CONCLUSION

The synergy between AI and CASP workflows has the potential to improve the planning precision and efficacy. However, there is a need for future studies with big data before the emergent technology finds application in a real clinical setting.

CLINICAL RELEVANCE

The implementation of AI models in maxillofacial CASP workflows could minimize a surgeon's workload and increase efficiency and consistency of the planning process, meanwhile enhancing the patient-specific predictability.

A mathematical algorithm of the facial symmetry plane: Application to mandibular deformity 3D facial data

The three-dimensional (3D) symmetry reference plane (SRP) is the premise and basis of 3D facial symmetry analysis. Currently, most methods for extracting the SRP are based on anatomical landmarks measured manually using a digital 3D facial model. However, as different clinicians have varying definitions of landmarks, establishing common methods suitable for different types of facial asymmetry remains challenging. The present study aimed to investigate and evaluate a novel mathematical algorithm based on power function weighted Procrustes analysis (PWPA) to determine 3D facial SRPs for patients with mandibular deviation. From 30 patients with mandibular deviation, 3D facial SRPs were determined using both our PWPA algorithms (two functions) and the traditional PA algorithm (experimental groups). A reference plane, defined by experts, was considered the 'truth plane'. The 'position error' index of mirrored landmarks was created to quantitatively evaluate the difference among the PWPA SRPs and the truth plane, including overall differences and regional differences of the face (upper, middle and lower). The 'angle error' values between the SRPs and the truth plane in the experimental groups were also evaluated in this study. Statistics and measurement analyses were used to comprehensively evaluate the clinical suitability of the PWPA algorithms to construct the SRP. The average angle error values between the PWPA SRPs of the two functions and the truth plane were 1.21 ± 0.65° and 1.18 ± 0.62°, which were smaller than those between the PA SRP and the truth plane. The position error values of mirrored landmarks constructed using the PWPA algorithms for the whole face and for each facial partition were lower than those constructed using the PA algorithm. In conclusion, for patients with mandibular deviation, this novel mathematical algorithm provided a more suitable SRP for their 3D facial model, which achieved a result approaching the true effect of experts.

[Preliminary clinical application verification of complete digital workflow of design lips symmetry reference plane based on posed smile]

OBJECTIVE

To automatically construct lips symmetry reference plane (SRP) based on posed smile, and to evaluate its advantages over conventional digital aesthetic design.

METHODS

Eighteen subjects' three-dimensional facial and dentition data were gathered in this study. The lips SRP of experimental groups were used with the standard weighted Procrustes analysis (WPA) algorithm and iterative closest point (ICP), respectively. A reference plane defined by experts based on regional ICP algorithm, served as the truth plane. The angle error values between the lips SRP of WPA algorithm in the experimental groups and the truth plane were evaluated in this study, and the lips SRP of ICP algorithm of the experimental groups was calculated in the same way. The lips SRP based on posed smile as a reference for aesthetic design and evaluate preliminary clinical application.

RESULTS

The average angle error between the lips SRP of WPA algorithm and the truth plane was 1.78°±1.24°, which was smaller than that between the lips SRP of ICP and the truth plane 7.41°±4.31°. There were significant differences in the angle errors among the groups (P < 0.05). In the aesthetic design of anterior teeth, automatically constructing the lips SRP of WPA algorithm based on posed smile and the original symmetry plane by re-ference compared with the prosthetic design, the subjects' scores on the lips SRP of WPA algorithm based on posed smile (8.48±0.57) were higher than those on the original symmetry plane (5.20±1.31).

CONCLUSION

Automatically constructing the lips SRP of WPA algorithm based on posed smile was more accurate than ICP algorithm, which was consistent with the truth plane. Moreover, it can provide an important reference for oral aesthetic diagnosis and aesthetic analysis of the restoration effect. In the aesthetic design of anterior teeth, automatically constructing the lips SRP of WPA algorithm based on posed smile can improve the patients' satisfaction in esthetic rehabilitation.

A Novel Study on Alar Mobility of HAN Female by 3dMD Dynamic Surface Imaging System

AIM

The aim of this study is to conduct a quantitative analysis on alar mobility of HAN females and provided referenced materials for alar dynamic aesthetic.

METHODS

One hundred and fifty healthy HAN females without rhinoplasty, nasal injury, nasal deformity and craniofacial deformity were included in this study. 3dMD surface imaging system was used for anthropometric analysis. All participants were instructed to perform the desired dynamic facial expression from rest to maximum smile without reveling teeth and recorded by 3dMD dynamic surface imaging system simultaneously. Two frames of rest status and alar maximum enlargement were selected for measuring alar width, alar base width and inner-canthal distance. The difference between two status represented alar mobility, which was generated through equation: [Formula: see text].

RESULTS

Alar mobility consisted of alar flaring mobility and alar base mobility. The alar flaring mobility was (9.49 ± 4.90)%, reference range was(1.45, 17.53)% and regression equation between rest and maximum smile was Y = 7.953 + 0.886X (R² = 0.641, p = 0.000); the alar base mobility was (17.94 ± 10.44)%, reference range was (0.88, 35.00)% and regression equation between rest and maximum smile was Y = 4.481 + 0.966X (R² = 0.528, p = 0.000.

CONCLUSION

Asian alar anatomy has great distinction from Caucasian, processing conspicuous alar movement and damaging alar aesthetic dynamically. This study novelly defined alar mobility by three-dimensional anthropometric analysis, providing objective references for alar dynamic aesthetic and arousing plastic surgeons' attention on keeping balance of static and dynamic aesthetic in rhinoplasty.

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 .

Current Applications of Artificial Intelligence in Cleft Care: A Scoping Review

Objective: This scoping review aims to identify the various areas and current status of the application of artificial intelligence (AI) for aiding individuals with cleft lip and/or palate.

Introduction: Cleft lip and/or palate contributes significantly toward the global burden on the healthcare system. Artificial intelligence is a technology that can help individuals with cleft lip and/or palate, especially those in areas with limited access to receive adequate care.

Inclusion Criteria: Studies that used artificial intelligence to aid the diagnosis, treatment, or its planning in individuals with cleft lip and/or palate were included.

Methodology: A search of the Pubmed, Embase, and IEEE Xplore databases was conducted using search terms artificial intelligence and cleft lip and/or palate. Gray literature was searched using Google Scholar. The study was conducted according to the PRISMA- ScR guidelines.

Results: The initial search identified 458 results, which were screened based on title and abstracts. After the screening, removal of duplicates, and a full-text reading of selected articles, 26 publications were included. They explored the use of AI in cleft lip and/or palate to aid in decisions regarding diagnosis, treatment, especially speech therapy, and prediction.

Conclusion: There is active interest and immense potential for the use of artificial intelligence in cleft lip and/or palate. Most studies currently focus on speech in cleft palate. Multi-center studies that include different populations, with collaboration amongst academicians and researchers, can further develop the technology.

Convolutional Neural Network Models for Automatic Preoperative Severity Assessment in Unilateral Cleft Lip

BACKGROUND

Despite the wide range of cleft lip morphology, consistent scales to categorize preoperative severity do not exist. Machine learning has been used to increase accuracy and efficiency in detection and rating of multiple conditions, yet it has not been applied to cleft disease. The authors tested a machine learning approach to automatically detect and measure facial landmarks and assign severity grades using preoperative photographs.

METHODS

Preoperative images were collected from 800 unilateral cleft lip patients, manually annotated for cleft-specific landmarks, and rated using a previously validated severity scale by eight expert reviewers. Five convolutional neural network models were trained for landmark detection and severity grade assignment. Mean squared error loss and Pearson correlation coefficient for cleft width ratio, nostril width ratio, and severity grade assignment were calculated.

RESULTS

All five models performed well in landmark detection and severity grade assignment, with the largest and most complex model, Residual Network, performing best (mean squared error, 24.41; cleft width ratio correlation, 0.943; nostril width ratio correlation, 0.879; severity correlation, 0.892). The mobile device-compatible network, MobileNet, also showed a high degree of accuracy (mean squared error, 36.66; cleft width ratio correlation, 0.901; nostril width ratio correlation, 0.705; severity correlation, 0.860).

CONCLUSIONS

Machine learning models demonstrate the ability to accurately measure facial features and assign severity grades according to validated scales. Such models hold promise for the creation of a simple, automated approach to classifying cleft lip morphology. Further potential exists for a mobile telephone-based application to provide real-time feedback to improve clinical decision making and patient counseling.

Assessing Facial Symmetry and Attractiveness using Augmented Reality

Facial symmetry is a key component in quantifying the perception of beauty. In this paper, we propose a set of facial features computed from facial landmarks which can be extracted at a low computational cost. We quantitatively evaluated the proposed features for predicting perceived attractiveness from human portraits on four benchmark datasets (SCUT-FBP, SCUT-FBP5500, FACES and Chicago Face Database). Experimental results showed that the performance of the proposed features is comparable to those extracted from a set with much denser facial landmarks. The computation of facial features was also implemented as an augmented reality (AR) app developed on Android OS. The app overlays four types of measurements and guidelines over a live video stream, while the facial measurements are computed from the tracked facial landmarks at run time. The developed app can be used to assist plastic surgeons in assessing facial symmetry when planning reconstructive facial surgeries.

[A method for constructing three-dimensional face symmetry reference plane based on weighted shape analysis algorithm]

OBJECTIVE

To establish a novel method based on three-dimensional (3D) shape analysis and weighted Procrustes analysis (WPA) algorithm to construct a 3D facial symmetry reference plane (SRP), automatically assigning weight to facial anatomical landmarks. The WPA algorithm suitability for commonly observed clinical cases of mandibular deviation were analysed and evaluated.

METHODS

Thirty patients with mandibular deviation were recruited for this study. The 3D facial SRPs were extracted independently based on original-mirror alignment method. Thirty-two anatomical landmarks were selected from the overall region by three times to obtain the mean coordinate. The SRP of experimental groups 1 and 2 were using the standard Procrustes analysis (PA) algorithm and WPA algorithm, respectively. A reference plane defined by experts based on regional iterative closest point (ICP) algorithm, served as the ground truth. Three experts manually selecting facial regions with good symmetry for original model, and common region was included in the study. The angle error values between the SRP of WPA algorithm in the experimental group 1 and the truth plane were evaluated in this study, and the SRP of PA algorithm of experimental group 2 was calculated in the same way. Statistics and measurement analysis were used to comprehensively evaluate the clinical suitability of the WPA algorithm to calculate the SRP. A paired t-test analysis (two-tailed) was conducted to compare the angles.

RESULTS

The average angle error between the SRP of WPA algorithm and the ground truth was 1.53°±0.84°, which was smaller than that between the SRP of PA and the ground truth (2.06°±0.86°). There were significant differences in the angle errors among the groups (P < 0.05). For the patients with severe mandibular deviation that the distance between pogonion and facial midline greater than 12 mm, the average angle error of the WPA algorithm was 0.86° smaller than that of the PA algorithm.

CONCLUSION

The WPA algorithm, based on weighted shape analysis, can provide a more adaptable SRP than the standard PA algorithm when applied to mandibular deviation patients and preliminarily simulate the diagnosis strategies of clinical experts.

A novel method for 3D face symmetry reference plane based on weighted Procrustes analysis algorithm

BACKGROUND

We aimed to establish a novel method, using the weighted Procrustes analysis (WPA) algorithm, which assigns weight to facial anatomical landmarks, to construct a three-dimensional facial symmetry reference plane (SRP) for mandibular deviation patients.

METHODS

Three-dimensional facial SRPs were independently extracted from 15 mandibular deviation patients using both our WPA algorithm and the standard PA algorithm. A reference plane was defined to serve as the ground truth. To determine whether the WPA SRP or the PA SRP was closer to the ground truth, we measured the position error of mirrored landmarks, the facial asymmetry index (FAI) error, and the angle error for the global face and each facial third partition.

RESULTS

The average angle error between the WPA SRP and the ground truth was 1.66 ± 0.81°, which was smaller than that between the PA SRP and the ground truth. The position error of the mirrored landmarks constructed using the WPA algorithm in the global face (3.64 ± 1.53 mm) and each facial partition was lower than that constructed using the PA algorithm. The average FAI error of the WPA SRP was - 7.77 ± 17.02 mm, which was smaller than that of the PA SRP.

CONCLUSIONS

This novel automatic algorithm, based on weighted anatomic landmarks, can provide a more adaptable SRP than the standard PA algorithm when applied to severe mandibular deviation patients and can better simulate the diagnosis strategies of clinical experts.

Validation of the Hubli Grading System for Assessing Unilateral and Bilateral Cleft Lip Outcomes

BACKGROUND

When determining whether a cleft lip repair outcome is acceptable, the severity of a patient's cleft at initial presentation must be considered. Currently, there is not a widely agreed upon scale for grading the pre-operative severity or post-operative surgical outcome for patients with unilateral and/or bilateral cleft lip. The aim of this study is to validate the Hubli grading system as a reliable and reproducible system for characterizing cleft lip repair outcomes.

METHODS

Craniofacial surgeon graders independently evaluated 2489 patients from 56 different countries undergoing both unilateral and bilateral cleft lip repair from April 2004 to December 2018. Preoperative severity and postoperative surgical results were assessed, and these grades were combined to determine surgical outcome acceptability based on initial cleft severity. Intrarater and interrater reliability were calculated as percentages of agreement.

RESULTS

Intrarater and interrater acceptability scores had an agreement of 94.50% and 87.04%, respectively. These results indicate that using the Hubli grading system, independent raters are able to reliably and reproducibly measure the acceptability of a cleft lip repair.

CONCLUSIONS

This study validates the use of the Hubli grading system to evaluate the acceptability of unilateral and bilateral cleft lip repairs. This is the largest study to date to evaluate cleft lip severity and repair outcomes, and the Hubli grading system is the only scale to determine the acceptability of surgical outcomes based on initial cleft severity. This system is designed to identify surgeons with sub-optimal outcomes in order to implement timely, individualized training on a global scale.

Unilateral Cleft Lip Nasal Deformity: Three-Dimensional Analysis of the Primary Deformity and Longitudinal Changes following Primary Correction of the Nasal Foundation

BACKGROUND

Objective assessment of the unilateral cleft lip nasal deformity and the longitudinal changes with treatment is critical for optimizing cleft care.

METHODS

Consecutive patients undergoing cleft lip repair and foundation-based rhinoplasty were included (n = 102). Three-dimensional images preoperatively, postoperatively, and at 5 years of age were assessed and compared to age-matched controls. Images were normalized to standard horizontal, craniocaudal, and anteroposterior axes.

RESULTS

Cleft subalare was similar in position relative to controls but was 1.6 mm retrodisplaced. Subnasale was deviated 4.6 mm lateral to midline and had the greatest displacement of any landmark. Noncleft subalare was displaced 2.3 mm laterally. Regression analysis with deviation of subnasale from the midline as a dependent variable revealed progressive lateral displacement of noncleft subalare, narrowing of noncleft nostril, and intercanthal widening. Surgery corrected nasal base displacements along all axes, resulting in landmark positions similar to controls. Symmetry of nasal base correction persisted at 5-year follow-up, with no recurrent cleft alar base retrusion, regardless of initial cleft type.

CONCLUSIONS

Unilateral cleft lip nasal deformity may be "driven" by displacement of the anterior nasal spine and caudal septum. The cleft alar base is normal in position but retruded, whereas the noncleft alar base is displaced laterally. Changes with surgery involve anterior movement of the cleft alar base but also include medial movement of the noncleft alar base and columella. Symmetry of correction, including alar base retrusion, was stable over time and did not rely on alveolar bone grafting.

Primary Rhinoplasty Does Not Interfere with Nasal Growth: A Long-Term Three-Dimensional Morphometric Outcome Study in Patients with Unilateral Cleft

BACKGROUND

Primary rhinoplasty has not been universally adopted because the potential for nasal growth impairment remains an unsolved issue in cleft care. This study's purpose was to assess the long-term effects of primary rhinoplasty performed by a single surgeon in a cohort of patients with a unilateral cleft lip nose deformity.

METHODS

Three-dimensional nasal morphometric measurements (linear, angular, proportional, surface area, and volume) were collected from consecutive patients (cleft group, n = 52; mean age, 19 ± 1 year) who had undergone primary rhinoplasty with the use of the Noordhoff approach between 1995 and 2002 and reached skeletal maturity. Normal age-, sex-, and ethnicity-matched subjects (control group, n = 52) were identified for comparative analyses.

RESULTS

No significant differences (all p > 0.05) were observed for most measures, including nasal height, alar width, nasal dorsum angle, columellar angle, columellar-labial angle, nasal tip/height ratio, nasal index, alar width/intercanthal distance ratio, nasal surface area, and nasal volume. The cleft group displayed significantly (all p < 0.05) lower nasal bridge length and nasal tip projection, and greater nasal protrusion, tip/midline deviation, nasal tip angle, nasal tip protrusion width index, and alar width/mouth ratio values than the control group.

CONCLUSIONS

Primary rhinoplasty does not interfere with nasal growth as measured by three-dimensional photogrammetric analysis. Further imaging studies are required for the assessment of development in other anatomical nasal structures.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Fluctuating asymmetry of dynamic smiles in normal individuals

The aim of this study was to quantify the fluctuating dynamic facial asymmetry during smiling in a group of 'normal' adults, using three-dimensional (3D) motion facial capture technology. Fifty-four male and 54 female volunteers were recruited. Each subject was imaged using a passive markerless 3D motion capture system (DI4D). Eighteen landmarks were tracked through the 3D capture sequence. A facial asymmetry score was calculated based on either a clinically derived midline or Procrustes alignment; scores were based on the Euclidean distance between landmark pairs. Facial asymmetry scores were determined at three time points: rest, median, and maximum frame. Based on the clinically derived midline and on Procrustes alignment, the differences between male and female volunteers, as well as those at the three different time points, were not clinically significant. However, throughout a smile, facial and lip asymmetry scores increased over the duration of the smile. Fluctuating facial asymmetry exists within individuals, as well as between individuals. Procrustes superimposition and the clinically derived midline produced similar asymmetry scores and both are valid for symmetrical faces. However, with facial asymmetry, Procrustes superimposition may not be a valid measure, and the use of the clinically derived midline may be more appropriate, although this requires further investigation.

Three-Dimensional Assessment of Morphological Changes Following Nasoalveolar Molding Therapy in Cleft Lip and Palate Patients: A Case Report

The applications of computer-guided technologies for three-dimensional image analysis provide a unique opportunity to quantify the morphological dimensional changes of the face in a practical and convenient way. Symmetry of the nasolabial area is one of the main factors of facial attractiveness as well as being the main objective of the treatment of cleft lip and palate (CLP). Technological advances in computer-guided visualization modes and their applications to three-dimensional stereophotogrammetry provide more practical opportunities and alternatives for facial analysis. Each study, however, uses different protocols for the acquisition and analysis of three-dimensional images. In addition, each study identifies different anthropometric points and calculates linear and angular measurements with overlapping protocols. Therefore, it is appropriate to define a standardization of the three-dimensional analysis of CLP patients to compare the studies of different research centers. The aim of this report is to propose a protocol to standardize the acquisition and analysis of three-dimensional images to evaluate the three-dimensional changes in the nasolabial area in cleft lip and palate patients undergoing pre-surgical nasoalveolar molding (PNAM).

Pilot Study of Visual and Quantitative Image Analysis of Facial Surface Asymmetry in Unilateral Complete Cleft Lip and Palate

Objective:

To visualize and quantitatively analyze facial surface asymmetry following primary cleft lip repair in patients with unilateral cleft lip and palate (UCLP) and to compare this with noncleft controls.

Design:

Retrospective comparative study.

Patients:

Twenty-two patients with complete UCLP who underwent primary lip repair from 2009 to 2013 were enrolled in this study. The preserved 3-dimensional (3D) data of 23 healthy Japanese participants with the same age were used as controls.

Interventions:

All patients had received primary labioplasty in accordance with Cronin triangular flap method with orbicular oris muscle reconstruction.

Main Outcome Measures:

Shadow and zebra images established from moiré images, which were reconstructed from 3D facial data using stereophotogrammetry, were bisected and reversed by the symmetry axes (the middle line of the face). The discrepancies of the gravity and density between cleft and noncleft sides in 2 regions of interest, facial and lip areas, were then calculated and compared with those of healthy participants.

Results:

In the UCLP group, the mean discrepancies of gravity on shadow and zebra images were 1.76 ± 0.70 and 2.63 ± 1.72 pixels, respectively, in the facial area and 1.31 ± 0.36 and 3.83 ± 2.08 pixels, respectively, in the lip area. There was a significant difference in the mean discrepancies of gravity and density on zebra images in the lip area between the UCLP and control groups.

Conclusions:

Our image analysis of digital facial surface asymmetry in patients with UCLP provides visual and quantitative information, and it may contribute to improvements in muscle reconstruction on cleft lip repair.

Three-dimensional analyses of nasolabial forms and upper lip surface symmetry after primary lip repair in patients with complete unilateral cleft lip and palate

PURPOSE

To analyze three-dimensional (3D) nasolabial forms and upper lip surface symmetry after primary lip repair in children with unilateral cleft lip and palate (UCLP).

METHODS

Subjects were 22 Japanese children with complete UCLP who underwent primary lip repair and were followed-up for 4-6 years. The 3D coordinates of facial landmarks and the angle and radius of the approximate nasal alar circle were calculated. Upper lip surface symmetry was analyzed using histogram intersection.

RESULTS

The nasal tip and columella base were slightly dislocated to the cleft side, and the midpoint of Cupid's bow shifted to the non-cleft side. The nasal alar and the top of Cupid's bow were reconstructed at the same height, while the approximate nasal alar circle was smaller on the cleft side. The mean value of similarity for upper lip surface symmetry was 0.82; a subject with a higher value had more symmetrical contour lines in the visualized surface image.

CONCLUSIONS

Postoperative nasolabial forms were almost restored to symmetrical levels, while retaining a small nasal alar. Histogram intersection is applicable as a method for the quantitative evaluation of upper lip surface symmetry in UCLP.

Objective Assessment of the Unilateral Cleft Lip Nasal Deformity Using Three-Dimensional Stereophotogrammetry: Severity and Outcome

BACKGROUND

Optimization of care to correct the unilateral cleft lip nasal deformity is hampered by lack of objective measures to quantify preoperative severity and outcome. The purpose of this study was to develop a consensus standard of nasal appearance using three-dimensional stereophotogrammetry; determine whether anthropometric measurements could be used to quantify severity and outcome; and determine whether preoperative severity predicts postoperative outcome.

METHODS

The authors collected facial three-dimensional images of 100 subjects in three groups: 45 infants before cleft lip repair; the same 45 infants after cleft lip repair; and 45 children aged 8 to 10 years with previous repairs. Five additional age-matched unaffected control subjects were included in each group. Seven expert surgeons ranked images in each group according to nasal appearance. The rank sum score was used as consensus standard. Anthropometric analysis was performed on each image and compared to the rank sum score. Preoperative rank and anthropometric measurements were compared to postoperative rank.

RESULTS

Interrater and intrarater reliability was excellent (intraclass correlation coefficient, >0.76; Pearson correlation, >0.75) on each of the three image sets. Columellar angle, nostril width ratio, and lateral lip height ratio were highly correlated with preoperative severity and moderately correlated with postoperative nasal appearance. Postoperative outcome was associated with preoperative severity (rank and anthropometric measurement).

CONCLUSIONS

Consensus ranking of preoperative severity and postoperative outcome can be achieved on three-dimensional images. Preoperative severity predicts postoperative outcomes. Columellar angle, nostril width ratio, and lateral lip height ratio are objective measures that correlate with consensus ratings by surgeons at multiple ages.

Post-surgical effects on the maxillary segments of children with oral clefts: New three-dimensional anthropometric analysis

This study aimed to use new three-dimensional (3D) anthropometric analyses to verify the post-surgical effects on the maxillary segments of children with unilateral cleft lip and palate. The sample was composed by digitized dental models of 60 children with unilateral complete cleft lip and alveolus (UCLA) and complete unilateral cleft lip and palate (UCLP). The impressions were taken before cheiloplasty (T1), after cheiloplasty (T2), and after palatoplasty (T3). The 3D anthropometric analyses of digitized dental casts were obtained through a specific software. Intragroup changes were applied paired t test and Wilcoxon test (UCLA group) and for the UCLP group, repeated-measures analyses of variance followed by the Tukey test. For intergroup analyses, an independent t test and Mann-Whitney test were used. The palatal dimensional changes of UCLA group showed that the distances IC, I-T', and I-T significantly increased after cheiloplasty (p = 0.0002, p = 0.0007 and p < 0.0001, respectively). In the UCLP group, the IC' distance statistically decreased in the post-surgical periods (p < 0.0001), while the I-T distance increased (p < 0.0001). The IC distance increased after cheiloplasty (p < 0.0001). The I-T' distance increased between T2 and T3 with statistically significant differences (p = 0.0037). The intergroup analysis of palatal development (T2-T1) showed that the distances IC' and I-T' demonstrated a reduction of the dental arches growth of UCLP group compared with the UCLA group, with statistically significant differences. The new 3D anthropometric analysis showed that the development of the maxillary segments changed after surgical repair. The UCLP group demonstrated a reduction of the dental arches growth compared with the UCLA group.

Novel computer vision analysis of nasal shape in children with unilateral cleft lip

BACKGROUND

Optimization of treatment of the unilateral cleft lip nasal deformity (uCLND) is hampered by lack of objective means to assess initial severity and changes produced by treatment and growth. The purpose of this study was to develop automated 3D image analysis specific to the uCLND; assess the correlation of these measures to esthetic appraisal; measure changes that occur with treatment and differences amongst cleft types.

METHODS

Dorsum Deviation, Tip-Alar Volume Ratio, Alar-Cheek Definition, and Columellar Angle were assessed using computer-vision techniques. Subjects included infants before and after primary cleft lip repair (N = 50) and children aged 8-10 years with previous cleft lip (N = 50). Two expert surgeons ranked subjects according to esthetic nose appearance.

RESULTS

Computer-based measurements strongly correlated with rankings of infants pre-repair (r = 0.8, 0.75, 0.41 and 0.54 for Dorsum Deviation, Tip-Alar Volume Ratio, Alar-Cheek Definition, and Columellar Angle, p < 0.01) while all measurements except Alar-Cheek Definition correlated moderately with rankings of older children post-repair (r ∼ 0.35, p < 0.01). Measurements were worse with greater severity of cleft type but improved following initial repair. Abnormal Dorsum Deviation and Columellar Angle persisted after surgery and were more severe with greater cleft type.

CONCLUSIONS

Four fully-automated measures were developed that are clinically relevant, agree with expert evaluations and can be followed through initial surgery and in older children. Computer vision analysis techniques can quantify the nasal deformity at different stages, offering efficient and standardized tools for large studies and data-driven conclusions.

Extracting the symmetry of the human face from digital photographs

By defining a midline and selecting six pairs of the landmarks of the human face on digital photographs, we extracted the symmetry of the human face by means of digital techniques. As a first approach to the symmetry of the human face, the distances and the tilts from the midline, between similar landmarks, were computed and averaged, respectively. The procrustes analysis and the histogram of oriented gradients (HOG), applied on patches on the six pairs of the landmarks of the human face, were used as a second approach to the symmetry of the human face. To have a better estimation of the symmetry of the whole human face, the photographs in grayscale and color were cut on pairs of strips, equally spaced from the midline, and then the strips were compared by the HOG feature extractor. The symmetry of the human face was extracted from 89 photographs of human faces (37 females and 52 males, ages 28.67±6.65 and 35.65±12.2 years, respectively). The HOG feature extractor applied on strips for the photographs in color and grayscale provided more confident values for the symmetry of the human face, which was well correlated with the assigned value by the photographers and physiotherapists. Also, an experiment was performed to evaluate the attractiveness as a function of the human face symmetry; thus, two groups of men and women were asked to sort digital photographs of women and men according to the attractiveness of women/men on the photographs. The results show that the most selected digital photographs were those with the highest symmetry scores.

Measuring Symmetry in Children With Cleft Lip. Part 2: Quantification of Nasolabial Symmetry Before and After Cleft Lip Repair

OBJECTIVE

The first part of this study validated an automated computer-based method of identifying the three-dimensional midfacial plane in children with unrepaired cleft lip. The purpose of this second part is to develop computer-based methods to quantify symmetry and to determine the correlation of these measures to clinical expectations.

PARTICIPANTS

A total of 35 infants with unrepaired unilateral cleft lip and 14 infant controls.

INTERVENTIONS

Six computer-based methods of quantifying symmetry were developed and applied to the three-dimensional images of infants with unilateral cleft lip before and after cleft lip repair and to those of controls.

MAIN OUTCOME MEASURE

Symmetry scores for cleft type, changes with surgery, and individual subjects ranked according to cleft severity were assessed.

RESULTS

Significant differences in symmetry scores were found between cleft types and found before and after surgery. Symmetry scores for infants with unilateral cleft lip approached those of controls after surgery, and there was a strong correlation with ranked cleft severity.

CONCLUSIONS

Our computer-based three-dimensional analysis of nasolabial symmetry correlated with clinical expectations. Automated processing made measurement convenient. Use of these measures may help to objectively measure cleft severity and treatment outcome.