Facial Asymmetry in Children with Unicoronal Synostosis who have Undergone Craniofacial Reconstruction in Infancy

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.

Nasal monobloc osteotomy for correction of late nasal and orbital asymmetry of unicoronal synostosis: A morphometric and outcomes study

BACKGROUND

Craniofacial asymmetry associated with unicoronal synostosis (UCS) may persist into the teenage years despite surgery in infancy. This study evaluated outcomes following a nasal monobloc procedure by mobilizing a united nasomaxillary and bilateral medial orbital segment of bone (nasal monobloc) to perform corrective translational and rotational movement for secondary correction of residual nasal-orbital asymmetry associated with UCS.

METHODS

A retrospective review of all UCS patients treated with nasal monobloc at our institution was performed. Demographic information was recorded, and pre- and postoperative 2D imaging was used for morphometric outcome analysis. Outcomes and complications were tabulated.

RESULTS

The study included 14 patients (5 males, 9 females; mean age 14.6 years; range 9.6 to 22.5 years; mean follow-up 70.6 months range 12 to 132 months). Ancillary procedures (scar revision, forehead/orbital contouring, MEDPOR® augmentation) were performed in all patients at the time of the nasal monobloc. One patient underwent a repeat procedure 6 years later following technique modification. Additionally, another patient experienced late overgrowth of the frontal sinus with forehead asymmetry. The morphometric analysis demonstrated significant (p < 0.05) pre-op to post-op improvements in naso-orbital asymmetry, as demonstrated by horizontal orbital aperture ratio (0.88 vs 0.99), midline to exocanthion ratio (0.91 vs 0.98), orbital index ratio (1.15 vs 1.01), and midline discrepancy (7.1 degrees vs 2.7 degrees).

CONCLUSION

Nasal monobloc osteotomy provides a reasonable surgical treatment to improve both the nasal and orbital asymmetries associated with unicoronal synostosis, including frontal nasal deviation, basal nasal deviation, and orbital aperture asymmetry. It is important to note that confounding anatomic variables such as globe dystopia, strabismus, and scleral show may affect the perception of orbital symmetry.

Three-Dimensional Quantification of Postoperative Facial Asymmetry in Patients With Unilateral Cleft lip and Palate Using Facial Symmetry Plane

OBJECTIVE

To quantitatively assess three-dimensional (3D) soft tissue facial asymmetry in patients with unilateral cleft lip and palate (UCLP) who have undergone primary lip repair.

DESIGN

Clinical, retrospective, comparative, methodological study.

PATIENTS/PARTICIPANTS

Twenty patients with UCLP were selected after a review of the records.

INCLUSION CRITERIA

Complete UCLP; surgically treated without secondary repair. An age-matched and sex-matched Control group was employed.

MAIN OUTCOME MEASURES

A 3D facial symmetry plane (FSP) was obtained by superimposing the point clouds of the original 3D facial image excluding the surgical site and including lip and nose areas and those of a mirrored facial image using the iterative closest point (ICP) adjustment method. The discrepancies in the depth and angle of the normal vector of the facial surface of each point cloud between right and left sides (cleft and non-cleft sides in the UCLP group, respectively) based on FSP were calculated.

RESULTS

Facial asymmetry in the UCLP group was significantly greater than in the Control group regarding both the discrepancies in the depth (1.34 ± 0.62, 0.73 ± 0.32 pixels, respectively) (P = .0004) and surface angle (18.0 ± 5.88, 12.8 ± 4.0°, respectively) (P = .0024). Biaxial assessment of the discrepancies in the depth and surface angle allowed us to visually extract UCLP patients with greater facial asymmetry.

CONCLUSIONS

Facial asymmetry analysis based on 3D FSP effectively facilitates the facial asymmetry quantification and soft tissue surgical outcome evaluation in patients with UCLP.

Automated three-dimensional analysis of facial asymmetry in patients with syndromic coronal synostosis: A retrospective study

Craniosynostosis, characterized by premature fusion of one or more cranial sutures, results in a distorted skull shape. Only three studies have assessed facial asymmetry manually in unicoronal synostosis patients. It is therefore important to understand how uni- and bicoronal synostosis affect facial asymmetry with a minimum risk of human bias. An automated algorithm was developed to quantify facial asymmetry from three-dimensional images, generating a mean facial asymmetry (MFA) value in millimeters to reflect the degree of asymmetry. The framework was applied to analyze postoperative 3D images of syndromic patients (N = 35) diagnosed with Muenke syndrome, Saethre-Chotzen syndrome, and TCF12-related craniosynostosis with respect to MFA values from a healthy control group (N = 89). Patients demonstrated substantially higher MFA values than controls: Muenke syndrome (unicoronal 1.74 ± 0.40 mm, bicoronal 0.77 ± 0.21 mm), Saethre-Chotzen syndrome (unicoronal 1.15 ± 0.20 mm, bicoronal 0.69 ± 0.16 mm), and TCF12-related craniosynostosis (unicoronal 1.40 ± 0.51 mm, bicoronal 0.66 ± 0.05 mm), compared with controls (0.49 ± 0.12 mm). Longitudinal analysis identified an increasing MFA trend in unicoronal synostosis patients. Our study revealed higher MFA in syndromic patients with uni- and bicoronal synostosis compared with controls, with the most pronounced MFA in Muenke syndrome patients with unilateral synostosis. Bicoronal synostosis patients demonstrated higher facial asymmetry than expected given the condition's symmetrical presentation.

Unilateral Cleft Lip and Palate Has Asymmetry of Bony Orbits: A Retrospective Study

Facial asymmetry is common in unilateral clefts. Since virtual surgical planning (VSP) is becoming more common and automated segmentation is utilized more often, the position and asymmetry of the orbits can affect the design outcome. The aim of this study is to evaluate whether non-syndromic unilateral cleft lip and palate (UCLP) patients requiring orthognathic surgery have asymmetry of the bony orbits. Retrospectively, we analyzed the preoperative cone-beam computed tomography (CBCT) or computed tomography (CT) data of UCLP (n = 15) patients scheduled for a Le Fort 1 (n = 10) or bimaxillary osteotomy (n = 5) with VSP at the Cleft Palate and Craniofacial Center, Helsinki University Hospital. The width, height, and depth of the bony orbit and the distance between the sella turcica and infraorbital canal were measured. A volumetric analysis of the orbits was also performed. The measurements were tested for distribution, and the cleft side and the contralateral side were compared statistically with a two-sided paired t-test. To assess asymmetry in the non-cleft population, we performed the same measurements of skeletal class III patients undergoing orthognathic surgery at Päijät-Häme Central Hospital (n = 16). The volume of bony orbit was statistically significantly smaller (p = 0.014), the distance from the infraorbital canal to sella turcica was shorter (p = 0.019), and the anatomical location of the orbit was more medio-posterior on the cleft side than on the contralateral side. The non-cleft group showed no statistically significant asymmetry in any measurements. According to these preliminary results, UCLP patients undergoing orthognathic surgery show asymmetry of the bony orbit not seen in skeletal class III patients without a cleft. This should be considered in VSP for the correction of maxillary hypoplasia and facial asymmetry in patients with UCLP.

School-age outcomes in patients with unilateral coronal synostosis: comparison of fronto-orbital advancement and endoscopic strip craniectomy

OBJECTIVE

Outcomes research on unilateral coronal synostosis is mostly limited to the early postoperative period. This study examines facial asymmetry, desire for revision, and patient-reported outcomes at school age in children who received either endoscopic strip craniectomy with helmet therapy or fronto-orbital advancement (open repair).

METHODS

Patients with repaired unilateral coronal synostosis born between 2000 and 2017, with 3D photographs taken when they were between 3.5 and 8 years of age, were eligible for study inclusion. Three pairs of bilateral linear measurements and two angular measurements were taken. Parent- and physician-reported desire for revision and patient-reported outcomes (Patient-Reported Outcomes Measurement Information System cognitive function and Quality of Life in Neurological Disorders stigma scores) were collected from patient charts.

RESULTS

Thirty-five patients qualified, including 25 with open repair and 10 with endoscopic repair. The median patient ages at repair were 3 months and 8 months in the endoscopic and open groups, respectively. The average ages at final 3D photography were 5.8 years and 5.5 years in the endoscopic and open groups, respectively. Digital anthropometry revealed no significant differences in measures of facial asymmetry between the repair groups (p ≥ 0.211). Midface depth (tragion to subnasale) was significantly less symmetric at school age than other linear measures (F(2,102) = 9.14, p < 0.001). Forehead asymmetry was significantly associated with parent- and physician-reported desire for revision (p ≤ 0.006). No significant associations were found between physical asymmetry and patient-reported stigma or cognitive function (p > 0.046, Holm-Bonferroni correction).

CONCLUSIONS

Children who underwent open or endoscopic repair for unilateral coronal synostosis have comparable facial symmetry at school age, but midface depth remains highly asymmetrical in both groups. Forehead asymmetry at school age correlates with parent- and physician-reported desire for revision.

Reliability of automated topographic measurements for spine deformity

PURPOSE

This study introduces a novel surface-topographic scanning system capable of automatically generating a suite of objective measurements to characterize torso shape.

RESEARCH QUESTION

what is the reliability of the proposed system for measurement of trunk alignment parameters in patients with adolescent idiopathic scoliosis (AIS) and controls?

METHODS

Forty-six adolescents (26 with AIS and 20 controls) were recruited for a prospective reliability study. A series of angular, volumetric, and area measures were computed from topographic scans in each of three clinically relevant poses using a fully automated processing pipeline. Intraclass correlation coefficients (ICC(2,1)) were computed within (intra-) and between (inter-) raters. Measurements were also performed on a torso phantom.

RESULTS

Topographic measurements computed on a phantom were highly accurate (mean RMS error 1.7%) compared with CT. For human subjects, intra- and inter-rater reliability were both high (average ICC > 0.90) with intrinsic (pose-independent) measurements having near-perfect reliability (average ICC > 0.98).

CONCLUSION

The proposed system is a suitable tool for topographic analysis of AIS; topographic measurements offer an objective description of torso shape that may complement other imaging modalities. Further research is needed to compare topographic findings with gold standard imaging of spinal alignment, e.g., standing radiography.

CONCLUSION

clinical parameters can be reliably measured in a fully automated system, paving the way for objective analysis of symmetry, body shape pre/post-surgery, and tracking of pathology without ionizing radiation.

Facial Asymmetry in Nonsyndromic and Muenke Syndrome-Associated Unicoronal Synostosis: A 3-Dimensional Study Based on Facial Surfaces Extracted From CT Scans

OBJECTIVE

To quantify soft tissue facial asymmetry (FA) in children with nonsyndromic and Muenke syndrome-associated unicoronal synostosis (NS-UCS and MS-UCS), hypothesizing that MS-UCS presents with significantly larger FA than NS-UCS.

DESIGN

Retrospective cohort study.

PATIENTS AND METHODS

Twenty-one children (mean age: 0.6 years; range: 0.1-1.4 years) were included in the study (NS-UCS = 14; MS-UCS = 7). From presurgical computed tomography scans, facial surfaces were constructed for analysis. A landmark guided atlas was deformed to match each patient's surface, obtaining spatially detailed left-right point correspondence. Facial asymmetry was calculated in each surface point across the face, as the length (mm) of an asymmetry vector, with its Cartesian components providing 3 directions. Mean FA was calculated for the full face, and the forehead, eye, nose, cheek, mouth, and chin regions.

RESULTS

For the full face, a significant difference of 2.4 mm (P = .001) was calculated between the 2 groups, predominately in the transverse direction (1.5 mm; P < .001). The forehead and chin regions presented with the largest significant difference, 3.5 mm (P = .002) and 3.2 mm (P < .001), respectively; followed by the eye (2.4 mm; P = .004), cheek (2.2 mm; P = .004), nose (1.7 mm; P = .001), and mouth (1.4 mm; P = .009) regions. The transverse direction presented with the largest significant difference in the forehead, chin, mouth, and nose regions, the sagittal direction in the cheek region, and the vertical direction in the eye region.

CONCLUSIONS

Muenke syndrome-associated unicoronal synostosis presented with significantly larger FA in all regions compared to NS-UCS. The largest significant differences were found in the forehead and chin regions, predominantly in the transverse direction.

3D printing guided surgery in the treatment of unicoronal craniosynostosis orbital dysmorphology

PURPOSE

The purpose of our study was to improve the minor asymmetries of fronto-orbital advancement (FOA) by introducing a simple model to guide the FOA in unicoronal synostosis which may help saving time and cost.

METHODS

A retrospective analysis of 16 consecutive patients with unicoronal synostosis corrected by FOA guided by a guide model. Patients with syndromic craniosynostosis or associated craniofacial anomalies were excluded from the analysis. In all cases, 3D mirror image models were used for guiding unilateral fronto-orbital advancement. Demographic, perioperative, and follow-up data were collected for comparison. Cranial and orbital volumes were documented preoperatively and postoperatively and compared with the non-synostotic side. The postsurgical appearance of the face was documented photographically and then evaluated and scored using the Whitaker scoring system.

RESULTS

The study included nine males and seven females. The mean age of the patients at the time of the operation was 20.4 months. The mean follow-up duration was 36 months. Mean operative time was 170 min, mean anesthetic time was 230 min, mean blood loss was 50-80 ml, and the average hospital stay was 4.4 days. No relapse that required surgical correction was reported. There were improvements in the orbital indices and volume to be near equal to the normal side. Excellent to good results were obtained in all patients according to the Whitaker classification system.

CONCLUSION

Residual deformity after FOA mandates another tool to optimize the results. Our study introduced a simple, easy, and applicable method to guide the FOA with lesser asymmetries.

Craniofacial Asymmetry from One to Three Years of Age: A Prospective Cohort Study with 3D Imaging

Deformational plagiocephaly (DP) is considered a risk factor for facial asymmetry. This cohort-based, prospective, follow-up study used three-dimensional (3D) stereophotogrammetry to assess the development of facial asymmetry in a normal birth cohort and to investigate the impact of DP on facial asymmetry for the age range of one to three years. The study sample consisted of 75 children: 35 girls (47%) and 40 (53%) boys recruited from Oulu University Hospital. A total of 23 (31%) subjects had a history of DP in infancy. 3D facial images were obtained at the mean (SD) age of 1.01 (0.04) year old at T1 and 3.02 (0.14) years old at T2. To determine facial asymmetry, both landmark-based and surface-based facial symmetry methods were used. As measured with the surface-based methods, upper facial symmetry improved from T1 to T2 (p < 0.05). As measured with the landmark-based methods, facial symmetry improved on the upper and lower jaw from T1 to T2 (p < 0.05). The asymmetric effect of DP on the upper parts of the face tends to correct spontaneously during growth. Results indicate that previous DP does not seem to transfer to facial or occlusal asymmetry at the age of three years old.

Spatially Detailed 3D Quantification of Improved Facial Symmetry After Surgery in Children With Unicoronal Synostosis

OBJECTIVE

To assess improvement of soft-tissue facial symmetry in children surgically treated for unicoronal synostosis (UCS) in infancy, to correlate pre- and postsurgical facial asymmetry and to evaluate whether the improvement was visually recognizable.

DESIGN

Case-controlled follow-up.

PATIENTS/SETTINGS

Eleven Danish children diagnosed with UCS were included, 3 of whom had tested positive for Muenke mutation. Preoperative computed tomography scans and postoperative 3dMD surfaces were available for measurements. A control group of healthy children matched for age and sex was employed.

MAIN OUTCOME MEASURES

Pre- and postsurgical facial asymmetry was analyzed using a computerized method capable of objective and spatially detailed quantification in 3-dimension (transverse, vertical, and sagittal directions). Asymmetry was evaluated in the facial region and 6 subregions (forehead, mouth, eyes, nose, cheek, and chin).

RESULTS

The largest significant improvement was seen in the sagittal direction of the facial (1.9 mm), forehead (2.0 mm), and cheek (3.4 mm) regions. Small but significant improvements were also seen in the mouth, chin, and eye regions. No significant improvement was seen in the nose region. Significant correlations were found between the pre- and postsurgically calculated facial asymmetry and between calculated asymmetry and clinical validation scores.

CONCLUSIONS

All patients presented with improved facial symmetry after surgery and the improvements were visually recognizable. However, only 1 (9.1%) of the 11 patients reached a level of facial asymmetry as low as that seen in the control group. The best outcome was, in general, seen in cases with mild facial asymmetry presurgically.

Associations Between Genetic Data and Quantitative Assessment of Normal Facial Asymmetry

Human facial asymmetry is due to a complex interaction of genetic and environmental factors. To identify genetic influences on facial asymmetry, we developed a method for automated scoring that summarizes local morphology features and their spatial distribution. A genome-wide association study using asymmetry scores from two local symmetry features was conducted and significant genetic associations were identified for one asymmetry feature, including genes thought to play a role in craniofacial disorders and development: NFATC1, SOX5, NBAS, and TCF7L1. These results provide evidence that normal variation in facial asymmetry may be impacted by common genetic variants and further motivate the development of automated summaries of complex phenotypes.

The role of Nasoalveolar molding: A 3D Prospective analysis

Nasoalveolar molding (NAM) is commonly employed to reduce the alveolar segments into proper alignment and to improve nasal symmetry in patients with cleft lip and palate. This study examines the periodical progression of NAM treatment over time. 20 patients with complete unilateral cleft lip and palate were prospectively recruited. A 2 stage NAM treatment protocol was applied. Stage 1 involved adjustment of the alveolar segments (mean age 15.6 days), while Stage 2 added nasal stents and started average 43 days after stage 1. 3D images (n = 241) were obtained prior to NAM initiation and weekly until the end of treatment. The cleft lip area, bilateral nostril areas, and the nostril height and width were measured. Treatment was assessed in the Cleft (C) side and the Non-cleft (N). There was significant difference in the C/N ratio of the nostril area, width, and height at pre-treatment (0.9 ± 0.3, 4.1 ± 1.1, and 0.5 ± 0.2), at the end of stage 1 (1.1 ± 0.3, 2.2 ± 0.6, and 0.8 ± 0.2), and at the end of stage 2 treatment (1.8 ± 0.3, 1.8 ± 0.4, and 1.2 ± 0.1); p < 0.05. Comparative 3D analysis with dense sampling offers a precise methodology for showing effects of NAM treatment. The morphological changes achieved with NAM therapy occur in early treatment phase.