Longitudinal 3D assessment of facial asymmetry in unilateral cleft lip and palate

Objective: Longitudinal evaluation of asymmetry of the surgically managed unilateral cleft lip and palate (UCLP) to assess the impact of facial growth on facial appearance. Design: Prospective study. Setting: Glasgow Dental Hospital and School, University of Glasgow, United Kingdom Patients: Fifteen UCLP infants. Method: The 3-D facial images were captured before surgery, 4 months after surgery, and at 4-year follow-up using stereophotogrammetry. A generic mesh which is a mathematical facial mask that consists of thousands of points (vertices) was conformed on the generated 3-D images. Using Procustean analysis, an average facial mesh was obtained for each age-group. A mirror image of each average mesh was mathematically obtained for the analysis of facial dysmorphology. Facial asymmetry was assessed by measuring the distances between the corresponding vertices of the original and the mirror copy of the conformed meshes, and this was displayed in color-coded map. Results: There was a clear improvement in the facial asymmetry following the primary repair of cleft lip. Residual asymmetry was detected around the nasolabial region. The nasolabial region was the most asymmetrical region of the face; the philtrum, columella, and the vermillion border of the upper lip showed the maximum asymmetry which was more than 5 mm. Facial growth accentuated the underlying facial asymmetry in 3 directions; the philtrum of the upper lip was deviated toward the scar tissue on the cleft side. The asymmetry of the nose was significantly worse at 4-year follow-up (P < .05). Conclusion: The residual asymmetry following the surgical repair of UCLP was more pronounced at 4 years following surgery. The conformed facial mesh provided a reliable and innovative tool for the comprehensive analysis of facial morphology in UCLP. The study highlights the need of refining the primary repair of the cleft and the potential necessity for further corrective surgery

The characterisation of the craniofacial morphology of infants born with Zika virus:Innovative approach for public health surveillance and broad clinical applications

Background: This study was carried out in response to the Zika virus epidemic which constituted a public health emergency and to the 2019 WHO calling for strengthened surveillance for the early detection of related microcephaly. The main aim of the study was to phenotype the craniofacial morphology of microcephaly using novel approach and new measurements, relate the characteristics to brain abnormalities in Zika infected infants in Brazil to improve clinical surveillance. Methods: We captured 3D images of the face and the cranial vault of 44 Zika infected infants and matched healthy controls using 3D camera. The CT scans of the brain of the infected infants were analysed. The Principal Component Analysis (PCA) was applied to characterise the craniofacial morphology. In addition to the head circumference (HC), we introduced a new measurement, head height (HH) to measure the cranial vault. The level of brain abnormality present in the CT scans was assessed, the severity of parenchymal volume loss and ventriculomegaly was quantified. Findings: The PCA identified a significant difference (p <0.001) between the cranial vaults and the face of the Zika infants and that of the controls. Spearman's rank-order correlation coefficients show that the head height (HH) has a strong correlation (0.87 in Zika infants; 0.82 in Controls) with the morphology of the cranial vaults which are higher than the correlation with the routinely used head circumference (HC). Also, the head height (HH) has a moderate negative correlation (-0.48) with the brain abnormalities of parenchymal volume loss. Interpretation: We discovered that head height (HH), the most sensitive and discriminatory measure of the severity of cranial deformity which should be used for clinical surveillance of Zika syndrome, evaluation of other craniofacial syndromes and assessment of various treatment modalities

Assessment of regional asymmetry of the face before and after surgical correction of unilateral cleft lip

This study was carried out on 26 unilateral cleft lip and palate (UCLP) cases with mean age 3.6 ± 0.7 months.3D facial images were captured for each infant 2–3 days before the repair of cleft lip and at 4 months following surgery at a mean age of 8.2 ± 1.8 months, using a stereophotogrammetry imaging system. An iterative closest point (ICP) algorithm was used to superimpose the 3D facial model to its mirror image using VRMesh software. After the superimposition, the face model was divided into seven anatomical regions. Asymmetry of the entire face and of the anatomical regions was calculated by measuring the absolute distances between the 3D facial surface model and its mirror image. Colour maps were used to illustrate the patterns and magnitude of the facial asymmetry before and after surgery. There were significant decreases in the asymmetry scores for the nose, upper lip and the cheeks as a result of the surgical repair of cleft lips. Surgery did not change the magnitude of the asymmetry scores for the lower lip and chin. The main outcome of the findings of this innovative study is to inform the required surgical refinement of primary repair of cleft lip in order to minimise facial asymmetry and to guide secondary corrective surgery. We have presented a sensitive tool that could be used for comparative analysis of lip repair at various cleft centres

3D longitudinal evaluation of facial morphology of the surgically managed unilateral cleft lip and palate (UCLP) cases.

Introduction Modern society is passionate about beauty and aesthetics. According to a 2016 survey by the International Society of Aesthetic and Plastic Surgery, the demand for aesthetic surgery is more than ever. People’s perception and awareness of facial aesthetics has increased. Orofacial cleft is the most common facial dysmorphology, with prevalence about 1.46:1000 in Scotland. The aim of the initial surgical repair of cleft lip is to improve facial aesthetics and function, without interrupting facial growth. Nevertheless, facial asymmetry is a stigma in cleft patients, and revision surgery due to a patient or their parents’ dissatisfaction with the outcomes is not uncommon. Objective evaluation of facial asymmetry after primary surgical repair is valuable. It is an indication of the success of surgery, and it informs the surgeon of the magnitude and location of residual asymmetry. The evaluation of facial asymmetry has evolved significantly from landmark-based assessment to surface-based analysis. The latter provides a comprehensive evaluation of facial asymmetry by superimposing the original 3D model on its mirror copy. This permits the quantification and the visualisation of the disparity between the two halves of the face. Many studies evaluated facial asymmetry a few years after primary surgical repair. Longitudinal monitoring and quantifying of facial shape changes can potentially guide the surgeon to the optimal surgical technique. Only a few studies evaluated facial asymmetry before and after primary surgery, and their analysis was dependent on a set of facial landmarks that did not describe the asymmetry of facial surfaces between these landmarks. Unfortunately, the existing literature does not provide comprehensive longitudinal evaluation of facial asymmetry of cleft patients, and the impact of facial expression on residual facial asymmetry has not been fully investigated. Aim The aim of this study was the longitudinal evaluation of facial asymmetry of UCLP patients using an advanced facial analysis tool, and to compare the postoperative residual asymmetry with the control group. The study was carried out to assess the impact of growth and facial expression on residual facial asymmetry. Methodology This study was carried out on 30 UCLP patients. All the patients were Caucasian and underwent the same surgical protocol, which was carried out by the same surgeon at the Royal Hospital of Sick Children, Edinburgh. 3D facial images were captured for the patients, before surgery, at about 4 months after surgery and at four-year follow-up, at rest and at maximum smile using 3dMDface system. Historical data of 70 3D facial images of six-month-old non-cleft infants were also analysed in this study. Facial asymmetry was evaluated using a generic mesh. A generic facial mesh is a mathematical facial mask that consists of 7,190 vertices. The mesh was conformed on each 3D facial image. The conformed meshes were utilised to evaluate facial asymmetry using two methods: the average asymmetry, the total and regional facial asymmetry. The average asymmetry method involved the creation of four average faces for cleft patients: an average preoperative face, an average postoperative face, and two average faces at the four-year follow-up (one at rest and one at a maximum smile). The fifth average face was that of six-month-old non-cleft infants. A mirror copy for each average 3D facial model was created by reflecting it on a lateral arbitrary plane. The original and mirror models were superimposed, the absolute distances between corresponding points on the two surfaces were calculated and analysed in three directions (mediolateral, vertical and anteroposterior), to quantify facial asymmetry. The results were displayed in colour-coded maps. Asymmetry scores were obtained by calculating the median of the absolute distances between corresponding points for the total face, upper lip and nose. The asymmetry scores in the mediolateral, vertical and anteroposterior directions were also quantified. Statistical tests were applied to detect significant differences in asymmetry scores of the total face and each facial region between study groups (before surgery, after surgery and at four-year follow-up), and between surgically managed cleft group and the control group. The correlations of asymmetry scores of the total face, nose and upper lip before surgery, after surgery and at four-year follow-up were also investigated. Results Facial asymmetry in cleft patients was dramatically improved after surgery. However, the postoperative residual asymmetry of UCLP patients was significantly higher than the non-cleft infants in the three directions. Furthermore, facial asymmetry increased during growth, with main impact on the nose. Facial expressions accentuated the residual asymmetry. Specifically, there was considerable shifting of the upper lip toward the scar tissue of the affected side. The residual asymmetry of the nose at the four-year follow-up was correlated to initial nasal asymmetry and residual nasal postoperative asymmetry. The anteroposterior deficiency of the upper lip, nose and paranasal area was pronounced in the cleft group at all time intervals due to insufficient bony support of the cleft maxilla. Conclusions Cleft patients and their parents should be informed of the likelihood of residual asymmetry following surgery. Refinements in primary surgery are necessary. The superficial and deep fibres of the orbicularis muscle have to be accurately repaired according to the direction of the muscle fibres to avoid the shifting of the philtrum of the upper lip toward the scar tissue on the affected side. The orbicularis oris muscle has to be adequately dissected and rotated in the downward direction to eliminate the residual vertical deficiency at the corner of the mouth on the affected side. An incision in the internal lateral side of the nose should be considered to reduce this deficiency. The levator labii superioris alaeque nasi muscle of the cleft side has to be reflected and sutured to the corresponding muscle fibres on the other side, to avoid the residual shifting of the nose to the non-cleft side, and to eliminate the residual vertical deficiency of the alar base on the cleft side during smiling. Revision surgery should be delayed until completion of growth. Before lip revision surgery, it is necessary to evaluate the residual asymmetry when the face is at rest and during facial expressions. Consideration should be given to initial nasal asymmetry and residual postoperative nasal asymmetry. Patients should be informed about the expected need for revision surgery including rhinoplasty. We were able for the first time to quantify facial asymmetry in three directions which provided an insight into the cause of the residual facial asymmetry at rest and at maximum smile. The generic mesh is an innovative tool for the assessment of facial asymmetry