Progressive facial asymmetry as a result of early closure of the left coronal suture

Dipyridamole-loaded 3D-printed bioceramic scaffolds stimulate pediatric bone regeneration in vivo without disruption of craniofacial growth through facial maturity

This study investigates a comprehensive model of bone regeneration capacity of dypiridamole-loaded 3D-printed bioceramic (DIPY-3DPBC) scaffolds composed of 100% beta-tricalcium phosphate (β -TCP) in an immature rabbit model through the time of facial maturity. The efficacy of this construct was compared to autologous bone graft, the clinical standard of care in pediatric craniofacial reconstruction, with attention paid to volume of regenerated bone by 3D reconstruction, histologic and mechanical properties of regenerated bone, and long-term safety regarding potential craniofacial growth restriction. Additionally, long-term degradation of scaffold constructs was evaluated. At 24 weeks in vivo, DIPY-3DPBC scaffolds demonstrated volumetrically significant osteogenic regeneration of calvarial and alveolar defects comparable to autogenous bone graft with favorable biodegradation of the bioactive ceramic component in vivo. Characterization of regenerated bone reveals osteogenesis of organized, vascularized bone with histologic and mechanical characteristics comparable to native bone. Radiographic and histologic analyses were consistent with patent craniofacial sutures. Lastly, through application of 3D morphometric facial surface analysis, our results support that DIPY-3DPBC scaffolds do not cause premature closure of sutures and preserve normal craniofacial growth. Based on this novel evaluation model, this DIPY-3DPBC scaffold strategy is a promising candidate as a safe, efficacious pediatric bone tissue engineering strategy.

Photometric evaluation of cranial and facial symmetry in hemicoronal single suture synostosis treated with surgical fronto-orbital remodeling

OBJECTIVE

Evaluation of frontal vault symmetry and progressive facial symmetrization in a cohort of patients with hemicoronal single suture synostosis treated with a standardized cranioplasty and rigid fixation.

PATIENTS AND METHODS

Fifty-four patients with hemicoronal synostosis operated between 1999 and 2014 were reviewed retrospectively. Pre, immediately postoperative and yearly photographs from the top of the skull and frontal views of the face were taken with the same head position and projection. A photogrammetric method was applied to quantify the pre and postoperative contour changes. The anterior skull hemispheres were traced, divided into two equal parts and the areas were compared. Angular measurements obtained by the intersection of the interpupillary line and the glabella perpendicular vertical line were calculated. The average photographic follow-up was 6.8 years. Range 1-14 years.

RESULTS

The average advancement on the affected side was 18 mm (range: 16-23 mm). The pre-surgical cranial area on the affected side was increased on average 14.6 + 2.4% (range: 10-18%). The angular measurements documented the frontal symmetry obtained and the progressive improvement of facial symmetry.

CONCLUSION

Cranioplasty with rigid fixation achieved a stable correction of anterior plagiocephaly leading to subsequent symmetrical facial growth. Photogrammetry allowed fora quantitative long-term validation.

Facial twist (asymmetry) in isolated unilateral coronal synostosis: does premature facial suture fusion play a role?

BACKGROUND

Unilateral coronal synostosis (UCS) often causes notable facial twist in affected patients. This condition occurs when the midface deviates toward the synostotic side, and the lower face deviates away from the synostotic side. The exact underlying mechanism for this phenomenon remains unclear. It has been proposed that premature fusion of facial sutures may play a role in the formation of facial twist. The purpose of this study was to determine whether asymmetrical facial suture fusion is present in patients with UCS.

METHODS

A single-center retrospective study was designed. Our study group consisted of 23 patients with a confirmed diagnosis of isolated UCS. Our control group consisted of 17 age-matched patients with deformational plagiocephaly and 11 normocephalic control subjects. The computed tomography scans of the faces were examined for the presence of facial suture fusions on both synostotic and nonsynostotic sides. All results with P < 0.05 were considered statistically significant.

RESULTS

We found an increased incidence of fusion of the frontomaxillary, nasofrontal, and nasomaxillary sutures on the side of synostosis in UCS when compared with the nonsynostotic side and when compared with patients with deformational plagiocephaly or normocephalic patients.

CONCLUSIONS

Asymmetrical premature fusion of facial sutures can potentially be contributing to the facial twist that is seen in patients with UCS.

Effects of Le Fort I Osteotomy on the Nasopharyngeal Airway-6-Month Follow-Up

PURPOSE

The literature discussing the impact of a single Le Fort I osteotomy on nasopharyngeal airways is limited. This study assessed the volumetric changes in the nasopharyngeal airway after a single Le Fort I osteotomy and explored the correlation between these changes and 3-dimensional surgical movements of the upper jaw.

MATERIALS AND METHODS

This retrospective study was conducted in 40 patients who had undergone a single Le Fort I (maxillary advancement with or without impaction) to correct Class III malocclusion with maxillary hypoplasia. Preoperative (T1) and 6-month postoperative (T2) cone-beam computed tomographic (CBCT) scans of these patients were used for analysis. Maxillary surgical movements and volumetric changes in the nasopharyngeal airway were measured. The reproducibility of the measurements was evaluated using paired t tests and intraclass correlation coefficients. The Wilcoxon test and Pearson correlation coefficient were applied to evaluate the volumetric changes in the nasopharyngeal airway space and assess the correlations of these changes to the maxillary surgical movements.

RESULTS

Six patients were excluded from the study owing to major differences (>5°) in their head and neck posture between the T1 and T2 CBCT scans. The errors of the repeated measurements were insignificant (P > .05), with a high level of agreement (r = 0.99; P < .05) between the repeated digitization of the landmarks. There was a statistically significant impact of a Le Fort I osteotomy on the right maxillary sinus (decreased by 17.8%) and the lower retropalatal space (expanded by 17.3%; P < .05). The correlation between the change in airway volume and the magnitude of surgical maxillary movements was moderate (r = .4). Similarly, there was a moderate correlation between changes in the upper nasopharynx and those in the hypopharynx.

CONCLUSION

The single Le Fort I osteotomy was found to increase the retroglossal airway volume. This could be important for the treatment of obstructive sleep apnea in patients with maxillary deficiency. A long-term follow-up assessment of a larger sample with a functional assessment of airway would be beneficial to confirm these findings.

Effects of induced premaxillary suture fusion on the craniofacial morphology in growing rats

OBJECTIVE

Due to premaxillary rapid development and fusion with the maxilla at the fetus stage, the functions of the premaxillary suture still remain unclear. This study was designed to explore the effect of artificial induced premaxillary suture fusion on craniofacial morphology.

METHODS

Thirty Sprague Dawley rats were divided into control and experimental groups, with 3 week, 5 week and 8 week subgroups of five animals each. An incision was made in each rat along the premaxillary suture and cyanoacrylate was administered to immobilize the exposed premaxillary suture for experimental rats. No glue was applied to controls. Weights, dental impressions and radiographs were taken before and after surgery until sacrifice and used to determine the differences between groups using the one-way ANOVA test.

RESULTS

After immobilizing the premaxillary suture, significant changes in the craniofacial morphology were measured at the different time points. In the experimental groups, local changes occurred at the 3rd week. A global alteration in craniofacial morphology was apparent at the 8th week in the experimental group compared to the control. At each successive time point, craniofacial morphological alterations increased in rats with fused premaxillary sutures.

CONCLUSIONS

Induced premaxillary suture fusion can inhibit the growth of the premaxilla and cause extensive craniofacial morphological changes. These findings suggest that premaxillary suture fusion may be related to craniofacial malformation or malocclusion and to the formation of the flattened craniofacial profile in humans.

Asymmetry of the sphenoid bone and its suitability as a reference for analyzing craniofacial asymmetry

The purposes of this study were to evaluate the asymmetry of the sphenoid bone and to determine its suitability as a reference for analyzing asymmetry of the skull. Thirty-seven dry skulls from India were divided into group A (n = 18), with a right-left length discrepancy of less than 2 mm for both the external acoustic meatus-frontozygomatic suture and external acoustic meatus-subspinale, and group B (n = 19), with a right-left length discrepancy of more than 2 mm for either of these 2 parameters. The skulls were then examined with regard to the percentage of asymmetry of the sphenoid bone, the angles between the cranial base and the facial axis, and the distance between reference surfaces of the sphenoid bone and facial landmarks by 3-dimensional measurement system. The following results were obtained: 1. Asymmetry of the sphenoid bone, while slight, was found in both groups. There were no significant differences between the 2 groups. 2. The cranial base and the facial axis did not form a right angle in group A, and there were no significant differences between the 2 groups. 3. The distances between reference surfaces of the sphenoid bone and the lower landmarks of the facial bone were greater than those of the upper landmarks. 4. The external acoustic meatus was the most suitable reference for analysis of craniofacial asymmetry.

Development of plagiocephaly in rabbits with unicoronal synostosis

Human unicoronal synostosis results in plagiocephaly of the cranial vault due to predictable compensatory growth patterns of the contralateral coronal, sagittal, and ipsilateral squamosal sutures. The present study describes the development of plagiocephaly and tests compensatory growth predictions in a naturally occurring rabbit model of uncorrected unicoronal synostosis. Cranial vault and sutural growth data were collected from serial x-ray films in 70 normal rabbits and 19 rabbits with congenital unicoronal synostosis from 1.5 to 18 weeks of age. One-way analysis of variance results revealed that rabbits with unicoronal synostosis had significant (p < 0.05) growth inhibition at both coronal sutures and the contralateral frontonasal suture and a significantly wider (p < 0.05) cranial vault compared to controls. Paired Student's t-tests between affected and unaffected sides of the vault in rabbits with synostosis revealed significant (p < 0.05) asymmetry, with ipsilateral coronal sutures growing less than contralateral ones. Gross qualitative examination of the adult brains revealed severe asymmetry and anteroposterior reduction on the ipsilateral side. These results demonstrate that this congenital rabbit model effectively simulates human cranial vault growth predictions from unicoronal synostosis and produces a plagiocephalic morphology.

Experiments of nature: premature unicoronal cranial synostosis in mantled howler monkeys (Alouatta palliata)

In 1960 Adolph Schultz described several cases of plagiocephaly in a collection of mantled howler monkeys (Alouatta palliata) from the forests of Central America. Since then several more specimens have been described. These individuals make up one of the largest samples of nonhuman primates that are affected by craniosynostosis. In this study, we used finite element scaling analysis (FESA) to quantify morphologic differences between adult normal (N = 19) and plagiocephalic female howler monkeys (N = 4). FESA utilizes three dimensional coordinate data to provide detailed information on size and shape differences local to biologic landmarks. The relatively large number of plagiocephalic howler monkeys provides a natural means for examining hypotheses concerning patterns of dysmorphology associated with plagiocephaly. Comparison of our results to observations from the clinical literature reveals similarities in neurocranial and facial morphology among plagiocephalic humans and howler monkeys, but the direction and magnitude of local form differences between howler monkeys and humans indicate species-specific responses to sutural constraint. Few cases of craniosynostosis in nonhuman primates are known. The number of plagiocephalic howler monkeys suggests these monkeys may be particularly susceptible to some defect that leads to premature suture closure. If this is the case, then howler monkeys may be a good model to study the cause(s) of craniosynostosis.

Craniosynostosis update 1987

Information on craniosynostosis in this paper updates "Craniosynostosis: Diagnosis, Evaluation, and Management" (Cohen MM Jr: New York: Raven Press, 1986). It also discusses recent developments that were included in the book but need further explanation or emphasis. Subjects discussed are: epidemiology, etiology, sutural biology, growth and development, neurological and psychosocial aspects, surgery, cloverleaf skulls, craniosynostosis syndromes, and prenatal diagnosis. Under the subject of etiology, fetal head constraint, maternal thyroid disease, calcified cephalohematoma, teratogens, and delayed suture closure and Wormian bones are considered. An updating of 15 cloverleaf skull conditions includes four monogenic disorders, two chromosomal disorders, one disruption, one iatrogenic condition, and seven syndromes of unknown cause. Newly recognized disorders with cloverleaf skull include Beare-Stevenson cutis gyratum syndrome and Say-Poznanski syndrome. Craniosynostosis syndromes and associations discussed include acrocraniofacial dysostosis, Apert syndrome, Beare-Stevenson cutis gyratum syndrome, Calabro syndrome, calvarial hyperostosis, chromosomal craniostenosis, Cole-Carpenter type osteogenesis imperfecta, Crouzon syndrome, Curry-Jones syndrome, Curry variant of Carpenter syndrome, cutis aplasia and cranial stenosis, Fontaine-Farriaux syndrome, Gomex-López-Hernández syndrome, Hersh syndrome, hyper-IgE syndrome and craniostenosis, hypomandibular faciocranial dysostosis, Marfanoid features and craniostenosis, Pfeiffer-type cardiocranial syndrome, Pfeiffer-type dolichocephalosyndactyly, and Say-Barber syndrome.