Asymmetry of the parental craniofacial skeleton in orofacial clefting

Cephalometric analysis of parents of patients with cleft lip and/or palate

BACKGROUND

Cleft lip and/or palate (CL ± P) or isolated cleft palate (CP) are the most common congenital malformations of the face. Although there have been advances in prenatal diagnosis and the discovery of genetic markers, there has been no breakthrough in the identification of parents at risk of giving birth to a child with a cleft.

AIMS

To determine a possible phenotypic difference in the craniofacial morphology of parents of children with CL ± P and to investigate whether cephalometric analysis can help identify parents at risk of giving birth to a child with a cleft.

METHODS

Cephalometric data of 25 sets of parents having children with CL ± P were compared with that of 25 sets of parents of children without CL ± P. The study population was indigenous to North Karnataka. In all, 10 linear, 2 angular, and 5 triangular measurements were made on lateral cephalograms and compared using an unpaired t‑test.

RESULTS

The length of the posterior cranial base (S-Ba) in mothers was smaller in the study compared to the control group. Total facial height (N-Me) both in fathers and in the group with both parents, upper facial height in the group with both parents, and lower facial height (ANS-Me) in fathers was smaller in the study than in the control group. The area of the nasopharyngeal triangle (S-PNS-Ba) in mothers and that of the anterior maxillary triangle (S-N-A) in fathers was smaller in the study group than in the control group.

CONCLUSION

Parents of children with CL ± P showed variations in craniofacial morphology. Future research correlating cephalometric findings with genetic studies may indicate whether cephalometric analysis can be an adjunct to genetic tests for risk prediction among susceptible parents.

Comparison of craniomaxillofacial morphology in children with unilateral cleft lip and palate treated with/without presurgical nasoalveolar molding - a retrospective study with a mean age of 5 years

OBJECTIVES

To three-dimensionally assess differences in craniomaxillofacial skeletal development in patients with operated unilateral cleft lip and palate (UCLP) treated with/without presurgical nasoalveolar molding (PNAM) with a mean age of 5 years.

MATERIALS AND METHODS

Cone-beam CT radiographs of 30 patients with UCLP who had undergone PNAM and 34 patients with UCLP who did not receive PNAM were analyzed. The data were stored in DICOM file format and were imported into the Dolphin Imaging program for 3D image reconstruction and landmark identification. 33 landmarks, 17 linear and three angular variables representing craniofacial morphology were analyzed and compared by using the Mann-Whitney U tests.

RESULTS

The vast majority of linear variables and 3D coordinates of landmark points reflecting craniofacial skeletal symmetry were not significantly different between the two groups. In terms of craniofacial skeletal development, the PNAM group had a significantly smaller anterior nasal spine offset in the midsagittal plane and a greater maxillary length compared to the non-PNAM group.

CONCLUSIONS

Evaluations performed in early childhood showed that treatment with/without PNAM in the neonatal period was not a major factor influencing craniomaxillofacial hard tissue development in patients with UCLP; moreover, PNAM treatment showed significant correction of skeletal deviation at the base of the nose.

CLINICAL RELEVANCE

Follow-up in early childhood has shown that PNAM treatment administered during the neonatal stage does not impede maxillary development and has benefits in correcting nasal floor deviation. It is a viable option for improving nasal deformity in children with unilateral cleft lip and palate.

Simultaneous PSI-Based Orthognathic and PEEK Bone Augmentation Surgery Leads to Improved Symmetric Facial Appearance in Craniofacial Malformations

(1) The aim of the present study was to compare the outcome of facial symmetry after simultaneous digitally planned patient-specific implant (PSI-) based orthognathic surgery and polyether ether ketone (PEEK) bone augmentation in patients with craniofacial malformations. (2) To evaluate the outcome of the two different surgical approaches (conventional PSI-based orthognathic surgery versus simultaneous PSI-based orthognathic surgery with PEEK bone augmentation), a comparison of five different groups with a combination of the parameters (A) with vs. without laterognathia, (B) syndromic vs. non-syndromic, and (C) surgery with vs. without PEEK bone augmentation was conducted. The digital workflow comprised cone beam CT (CBCT) scans and virtual surgery planning for all patients in order to produce patient specific cutting guides and osteosynthesis plates. Additionally, deformed skulls were superimposed by a non-deformed skull and/or the healthy side was mirrored to produce PSI PEEK implants for augmentation. Retrospective analyses included posterior-anterior conventional radiographs as well as en face photographs taken before and nine months after surgery. (3) Simultaneous orthognathic surgery with PEEK bone augmentation significantly improves facial symmetry compared to conventional orthognathic surgery (6.5%P (3.2-9.8%P) (p = 0.001). (4) PSI-based orthognathic surgery led to improved horizontal bone alignment in all patients. Simultaneous PEEK bone augmentation enhanced facial symmetry even in patients with syndrome-related underdevelopment of both soft and hard tissues.

What’s Shape Got to Do With It? Examining the Relationship Between Facial Shape and Orofacial Clefting

Nonsyndromic orofacial clefts belong to a class of congenital malformations characterized by a complex and multifactorial etiology. During early facial development, multiple factors can disrupt fusion leading to a cleft; this includes the shape of the embryonic face. The face shape hypothesis (FSH) of orofacial clefting emerged in the 1960s, influenced by morphological differences observed within affected families, comparative studies of mouse models, and advances in modeling genetic liability for complex traits in populations. For the past five decades, studies have documented changes in the shape or spatial arrangement of facial prominences in embryonic mice and altered post-natal facial shape in individuals at elevated risk for orofacial clefting due to their family history. Moreover, recent studies showing how genes that impact facial shape in humans and mice are providing clues about the genetic basis of orofacial clefting. In this review, I discuss the origins of the FSH, provide an overview of the supporting evidence, and discuss ways in which the FSH can inform our understanding of orofacial clefting.

Breaking Symmetry: A Quantitative Analysis of Facial Skeleton Disharmony in Children Born with Bilateral Cleft Lip and Palate

Bilateral cleft lip and palate (BCLP) occurs when craniofacial precursors fail to form or fuse properly during development. The aim of this retrospective, cross-sectional investigation was to quantify directional asymmetry (DA) of the facial skeleton of children born with Veau Class IV nonsyndromic BCLP. To accomplish this goal, coordinate values of anatomical landmarks were acquired from three-dimensional cone beam computed tomographic images of the craniofacial skeleton of middle- to late-aged children born with BCLP and age- and sex-matched controls and used to compare patterns of asymmetry variation. Multivariate analyses revealed different patterns of DA variation across samples and identified approximately 30% of DA measures as significantly different. Magnitudes of statistically significant linear distances differ in the craniofacial region, with most smaller DA differences located near the orbits and frontal bone, while larger differences were localized mostly to the midface, alveolar ridge, and nasal borders. Generally, areas of the craniofacial skeleton derived from the maxillary and nasal prominences demonstrated the highest magnitudes of DA. The methods and results presented will be useful to biomedical researchers when identifying the extent to which patients with BCLP diverge from typical developmental expectations. Quantifying DA and assessing local differences across the craniofacial complex can aid medical practitioners when developing treatments to improve BCLP surgical algorithms and outcomes. Anat Rec, 302:1726-1732, 2019. © 2019 American Association for Anatomy.

Laterality and Left-sidedness in the Nose, Face, and Body: A New Finding

Background:

Asymmetry is a common occurrence in bilaterian animals, particularly human beings. Through examination of patients and their photographs during rhinoplasty, we noted wider left-sided nasal and facial features in most patients. This observation led us to hypothesize that this might be consistent to the whole body.

Methods:

We conducted a study in 3 parts to test the question above. First, we analyzed operating notes of 50 rhinoplasty patients to determine the wider side of the upper, middle, and lower thirds of the nose. Second, we analyzed the width of the face and chest wall in 31 patients to discern any correlation between facial and bodily asymmetry. Third, computerized tomographic scans of the thorax and body of 48 patients were studied to measure the width of the hemithorax and hemipelvic bone.

Results:

(1) Upper vault width was wider on left side (78%). Left middle vault width was wider (88%). The lower lateral cartilage, lateral crura convexity was more prominent on left side (48%), and a wider scroll area was found and trimmed in 21 (left) and 0 (right) cases. The alar base was wider on left side (56%). (2) In the body and face analysis, 64.5% had a wider left-sided face and body. (3) In the computed tomographic scan analysis, same-sided thorax and pelvis asymmetry was seen (85.35%), 33 and 7 of which were left- and right-sided, respectively.

Conclusion:

We observed generalized asymmetry of the face and body with left-sided predominance.

Prevalence of facial asymmetry in Tirupati population: A posteroanterior cephalometric and photographic study

AIMS AND OBJECTIVE

The human face is the most prominent aspect in human social interactions, and therefore, it seems reasonable opting for orthodontic treatment is to overcome psychosocial difficulties relating to facial and dental appearance and enhance the quality of life in doing so.

MATERIALS AND METHODS

Posteroanterior cephalograms and frontal photographs of 100 participants (50 males and 50 females) were analyzed to evaluate skeletal asymmetry by the analysis suggested by Grummons. Soft tissue facial asymmetry was analyzed by composite photographic analysis. The data were statistically analyzed using the Statistical Package for the Social Sciences version 16.0 software. Independent t-test was used to find the differences between different measurements.

RESULTS

All participants showed mild asymmetry and right-sided laterality. The difference between the right and left sides were statistically insignificant (P > 0.01). The test revealed that only Co distance was statistically significant (P < 0.01), and all the other values are not statistically significant.

CONCLUSION

Composite photographs of hundred participants revealed that facedness is towards the right, however, this laterality was not statistically significant. Both posteroanterior cephalograms and composite photographs showed right-sided laterality. Gender difference in both skeletal and soft tissue asymmetry is not statistically significant.

Exploratory genotype-phenotype correlations of facial form and asymmetry in unaffected relatives of children with non-syndromic cleft lip and/or palate

Family relatives of children with nonsyndromic cleft lip with or without cleft palate (NSCL/P) who presumably carry a genetic risk yet do not manifest overt oral clefts, often present with distinct facial morphology of unknown genetic etiology. This study investigates distinct facial morphology among unaffected relatives and examines whether candidate genes previously associated with overt NSCL/P and left-right body patterning are correlated with such facial morphology. Cases were unaffected relatives of individuals with NSCL/P (n = 188) and controls (n = 194) were individuals without family history of NSCL/P. Cases and controls were genotyped for 20 SNPs across 13 candidate genes for NSCL/P (PAX7, ABCA4-ARHGAP29, IRF6, MSX1, PITX2, 8q24, FOXE1, TGFB3 and MAFB) and left-right body patterning (LEFTY1, LEFTY2, ISL1 and SNAI1). Facial shape and asymmetry phenotypes were obtained via principal component analyses and Procrustes analysis of variance from 32 coordinate landmarks, digitized on 3D facial images. Case-control comparisons of phenotypes obtained were performed via multivariate regression adjusting for age and gender. Phenotypes that differed significantly (P < 0.05) between cases and controls were regressed on the SNPs one at a time. Cases had significantly (P < 0.05) more profile concavity with upper face retrusion, upturned noses with obtuse nasolabial angles, more protrusive chins, increased lower facial heights, thinner and more retrusive lips and more protrusive foreheads. Furthermore, cases showed significantly more directional asymmetry compared to controls. Several of these phenotypes were significantly associated with genetic variants (P < 0.05). Facial height and width were associated with SNAI1. Midface antero-posterior (AP) projection was associated with LEFTY1. The AP position of the chin was related to SNAI1, IRF6, MSX1 and MAFB. The AP position of the forehead and the width of the mouth were associated with ABCA4-ARHGAP29 and MAFB. Lastly, facial asymmetry was related to LEFTY1, LEFTY2 and SNAI1. This study demonstrates that, genes underlying lip and palate formation and left-right patterning also contribute to facial features characteristic of the NSCL/P spectrum.

A comparative study of facial asymmetry in philippine, colombian, and ethiopian families with nonsyndromic cleft lip palate

Objective. To compare the asymmetry displayed by Philippine, Colombian, and Ethiopian unaffected parents of patients with nonsyndromic cleft palate (NSCLP) and a control population. Methods. Facial measurements were compared between unaffected parents of NSCLP patients and those in the control group for three populations from South America, Asia, and Africa by anthropometric and photographic measurements. Fluctuating and directional asymmetries, height and width proportions, were analyzed and compared. Results. Fluctuating asymmetries (ear length, middle line to Zigion perpendicular for left and right sides) and variations in the facial thirds demonstrated statistical significance in the study group of unaffected parents from Colombia and Philippines, while increased interorbital distance was evident in the unaffected Ethiopian parents of NSCLP patients. Conclusions. The facial differences in unaffected parents could indicate an underlying genetic liability. Identification of these differences has relevance in the understanding of the etiology of NSCLP.

Spatially-dense 3D facial asymmetry assessment in both typical and disordered growth

Mild facial asymmetries are common in typical growth patterns. Therefore, detection of disordered facial growth patterns in individuals characterized by asymmetries is preferably accomplished by reference to the typical variation found in the general population rather than to some ideal of perfect symmetry, which rarely exists. This presents a challenge in developing an asymmetry assessment tool that is applicable, without modification, to detect both mild and severe facial asymmetries. In this paper we use concepts from geometric morphometrics to obtain robust and spatially-dense asymmetry assessments using a superimposition protocol for comparison of a face with its mirror image. Spatially-dense localization of asymmetries was achieved using an anthropometric mask consisting of uniformly sampled quasi-landmarks that were automatically indicated on 3D facial images. Robustness, in the sense of an unbiased analysis under increasing asymmetry, was ensured by an adaptive, robust, least-squares superimposition. The degree of overall asymmetry in an individual was scored using a root-mean-squared-error, and the proportion was scored using a novel relative significant asymmetry percentage. This protocol was applied to a database of 3D facial images from 359 young healthy individuals and three individuals with disordered facial growth. Typical asymmetry statistics were derived and were mainly located on, but not limited to, the lower two-thirds of the face in males and females. The asymmetry in males was more extensive and of a greater magnitude than in females. This protocol and proposed scoring of asymmetry with accompanying reference statistics will be useful for the detection and quantification of facial asymmetry in future studies.

Novel method of 3-dimensional soft-tissue analysis for Class III patients

INTRODUCTION

The aim of this study was to evaluate 3-dimensional facial shells by incorporating a population-specific average template with a group of Class III subjects preparing to have orthognathic surgery.

METHODS

The Class III group included 14 male (MCIII) and 15 female (FCIII) subjects. We used 43 male and 44 female Class I subjects to construct average male (AvM) and female (AvF) faces. Coordinates of 3 points on the facial templates of groups MCIII and FCIII and the templates AvM and AvF were compared. MCIII-AvM and FCIII-AvF superimpositions were evaluated for differences.

RESULTS

Vertical distances (sella to soft-tissue pogonion) were statistically significantly higher for the AvM (9.1%) and MCIII (10.1%) than for the AvF and FCIII, respectively (P < 0.05). The distances of soft-tissue pogonion in the horizontal x-axis were positive in 80% of the FCIII group and 85.7% of the MCIII group. The Class III subjects differed from the average face in the lower two thirds, but, in 50% (MCIII) and 60% (FCIII), they differed also in the upper facial third.

CONCLUSIONS

(1) The average and Class III Slovenian male morphologic face heights are statistically significantly higher than those of the female subjects. (2) The Slovenian Class III male and female subjects tend toward a left-sided chin deviation. (3) Differences between Class III patients and a normative data set were determined.

Asymmetry of the craniofacial skeleton in the parents of children with a cleft lip, with or without a cleft palate, or an isolated cleft palate

The objective of this study was to evaluate asymmetry of the parental craniofacial skeleton of subjects with a cleft lip, with or without cleft palate [CL(P)], and isolated cleft palate (CP). The postero-anterior (PA) cephalograms of 52 parents of children with CL(P) and 40 parents of children with CP from a sample of 196 children with non-syndromic clefts in the west of Scotland were analysed. A conventional cephalometric asymmetry analysis was used to evaluate size-related right:left asymmetry comprising eight linear distances, nine angular, and three facial area measurements. Right:left ratios of the mean values identified the direction of the asymmetry and two-sample t-tests determined statistical significance. A shape-related asymmetry analysis was also undertaken. The configurations of landmarks were optimally superimposed and scaled using Procrustes algorithms. Euclidean distance matrix analysis (EDMA) was then compared and the shape of the left and the right landmark configurations were statistically tested using a non-parametric bootstrap technique. For the parents of CL(P) children, size-related asymmetry was identified and the area of the craniofacial polygon was statistically significantly larger on the right than on the left side. EDMA detected the presence of shape-related asymmetry (T statistic = 1.304; P = 0.003). For the parents of CP children, although size-related asymmetry was identified, EDMA did not identify shape-related asymmetry (T statistic = 1.281; P = 0.065). Size and shape directional asymmetries are characteristic features of the parental craniofacial skeleton in CL(P). Although directional size asymmetry is present in the parental craniofacial skeleton in CP, shape asymmetry is not a characteristic feature.

Prenatal alcohol exposure alters the patterns of facial asymmetry

Directional asymmetry, the systematic differences between the left and right body sides, is widespread in human populations. Changes in directional asymmetry are associated with various disorders that affect craniofacial development. Because facial dysmorphology is a key criterion for diagnosing fetal alcohol syndrome (FAS), the question arises whether in utero alcohol exposure alters directional asymmetry in the face. Data on the relative position of 17 morphologic landmarks were obtained from facial scans of children who were classified as either FAS or control. Shape data obtained from the landmarks were analyzed with the methods of geometric morphometrics. Our analyses showed significant directional asymmetry of facial shape, consisting primarily of a shift of midline landmarks to the right and a displacement of the landmarks around the eyes to the left. The asymmetry of FAS and control groups differed significantly and average directional asymmetry was increased in those individuals exposed to alcohol in utero. These results suggest that the developmental consequences of fetal alcohol exposure affect a wide range of craniofacial features in addition to those generally recognized and used for diagnosis of FAS.

Facial asymmetry in young healthy subjects evaluated by statistical shape analysis

Statistical shape analysis, a relatively a new method for biological research, compares body forms by using specific landmarks determined by anatomical prominences. In this study, we aimed to identify normal facial asymmetry between the right and the left sides of the face. Facial landmark data were collected from two-dimensional digital images of 321 young healthy subjects (150 males and 171 females). These data were analysed using Euclidean distance matrix analysis. The number of significantly asymmetric linear distances between the two halves of the face was greater in females than in males. We found that the left side of the face was most commonly dominant in both males and females. Such data may be useful in establishing a database for future similar studies.

Parental craniofacial morphology in cleft lip with or without cleft palate as determined by cephalometry: a meta-analysis

OBJECTIVE

To integrate findings from previous cephalometric studies comparing the craniofacial complex of unaffected parents with cleft lip with or without cleft palate (CL/P) children to controls with no history of the disease.

DESIGN

Meta-analysis of case-control cephalometric data.

INCLUSION CRITERIA

Studies were selected if the unaffected parents of children with CL/P were included and were not combined with parents of children with isolated CP; quantitative data were obtained through cephalometry; the cephalometric variables used were not unique to a study; a case-control design was used; and the means and standard deviations for all variables were reported or could be calculated for both the experimental and the control group.

OUTCOME MEASURE

Using raw data obtained from nine studies, mean weighted effect sizes with 95% confidence intervals were calculated for 28 cephalometric variables (mothers and fathers combined) or 18 variables (mothers and fathers separately). Heterogeneity statistics for the effect sizes were also calculated.

RESULTS

In general, unaffected parents of children with CL/P possessed significantly wider interorbital, nasal cavity and upper facial dimensions, narrower cranial vaults, longer cranial bases, longer and more protrusive mandibles, shorter upper faces and longer lower faces compared with controls. Increased width of the nasal cavity was the most robust finding. Significant effect size heterogeneity was observed in roughly half of the variables examined.

CONCLUSION

Unaffected parents of children with CL/P are characterized by a suite of consistent, yet subtle, craniofacial differences, which could indicate an underlying genetic liability.

Predisposing factors to formation of cleft lip and palate: inherited craniofacial skeletal morphology

OBJECTIVE

To identify inherited craniofacial morphologic features in individuals at high risk for cleft of the lip, cleft palate, or both.

SUBJECTS

Twins without cleft from 33 pairs of monozygotic twins discordant for cleft lip, cleft palate, or both were studied. There were 17 males and 16 females of Caucasian origin, ranging from 3 to 18 years (15 with cleft lip and palate [CLP], 10 with cleft lip [CL], and 8 with cleft palate [CP]), collected from five craniofacial centers (United States and Canada).

DESIGN

The twin without cleft (noncleft) from each set was compared with an age- and sex-matched control individual from the Burlington Growth Centre, Toronto, Ontario. Posteroanterior and lateral cephalograms were traced and digitized using a computer custom analysis. Descriptive statistics, Student's t tests, and analysis of variance were used to test 40 variables in a pilot study comparing the noncleft twin groups with the controls. Preliminary analysis permitted pooling of the CLP and CL groups (n = 25). To minimize false-positive significance, only 14 variables (from the maxillofacial area) were tested.

RESULTS

Using the raw probabilities, eight variables showed significant differences between the pooled noncleft CLP and CL (CL[P]) twin group and the controls. However, when the level of significance was adjusted, only four (nasal width [p < .01], cranial base length [p < .05], cranial base width/length ratio [p < .001], and maxillary width/length ratio [p < .05]) were significantly different. No significant differences were confirmed between the noncleft CP twin group and the controls.

CONCLUSIONS

The noncleft member of a discordant monozygotic pair has a number of facial characteristics that differ from the general population. These may predispose to the formation of a cleft lip or palate and may result from a deficiency or distortion of the mesenchyme that forms the craniofacial structures.

Three-dimensional assessment of facial soft-tissue asymmetry before and after orthognathic surgery

We developed a new three-dimensional (3D) method of analysis of facial asymmetry and applied it to 44 patients: 20 Class III cases treated by bimaxillary osteotomy; 12 Class III cases treated by maxillary advancement alone, and 12 Class II cases treated by bimaxillary operations. 3D images were taken within a week before operation (T1), and one (T2), three (T3), and six (T4) months after operation. Landmarks were digitised on each 3D model and facial asymmetry scores were calculated. In the bimaxillary osteotomy group, facial symmetry improved after operation. In the maxillary advancement group, there was no notable improvement in facial symmetry after operation. In the bimaxillary group, facial symmetry deteriorated after operation, particularly at the tip of the nose and prominence of the chin. At six months follow-up, the changes in facial asymmetry in the three groups were not significant.