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Clinical Biomechanics (Bristol, Avon) Jun 2021Craniosynostosis in newborns is caused by the premature closure of the cranial sutures leading to cranial vault deformity. It results in aesthetic imbalance and...
BACKGROUND
Craniosynostosis in newborns is caused by the premature closure of the cranial sutures leading to cranial vault deformity. It results in aesthetic imbalance and developmental disabilities and surgery is frequent during the first months of growth. Our study focused on scaphocephaly defined as the premature closure of the sagittal suture. We hypothesised that the effective mechanical properties of sutures were altered as compared to those of the parietal adjacent tissue considered as control.
METHODS
The population consisted of seven males and four females (mean age 4.9 months). Sixteen suture samples and thirty-four parietal tissue samples were harvested during corrective surgery and investigated by using three-point bending tests to obtain the structure-stiffness of specimens. An energy model was used to derive the effective Young's modulus. A histological study complemented the experimental protocol.
FINDINGS
Fused sutures were thicker than adjacent bone and the natural curvature of sutures did not influence the static mechanical response. The stiffness of stenotic sutures was significantly higher than that of the parietal bone. The effective Young's modulus of stenotic sutures was significantly lower than that of the parietal adjacent tissue. The parietal tissue showed a parallel bone architecture whereas the central stenotic tissue was disorganised with more vascularisation.
INTERPRETATION
The stenotic suture differed in structural and mechanical terms from the adjacent bone during calvarial growth in the first year of life. Our study emphasised the alteration of effective tissue properties in craniosynostosis.
Topics: Cranial Sutures; Craniosynostoses; Female; Humans; Infant; Infant, Newborn; Male; Skull; Sutures
PubMed: 34000627
DOI: 10.1016/j.clinbiomech.2021.105369 -
American Journal of Orthodontics and... Mar 2023Orthopedic appliances continue to be used for various sagittal, vertical, and transverse corrections of the maxilla. Although cranial growth can continue to adulthood,...
INTRODUCTION
Orthopedic appliances continue to be used for various sagittal, vertical, and transverse corrections of the maxilla. Although cranial growth can continue to adulthood, no study has drawn attention to the effects of headgear forces on the calvarium, in which anchorage is taken. This study focused on the different biomechanical responses on the calvarium of young children wearing a high-pull headgear of varying forces, using a 3-dimensional finite element analysis and the possible implications of such changes on the human skull.
METHODS
A 3-dimensional finite element model of a 9-year-old child was designed from the computed tomography scan. The material properties of the juvenile skull were assigned. Varying orthopedic forces (400, 500, and 600 g of force) were applied, and the magnitude of displacement and stresses generated on the cranial bones and sutures were interpreted using ANSYS software (version 12.1; Canonsburg, Pa).
RESULTS
Maximum displacement was found for the parietal bone in the inferior direction; parietal and temporal bones in the transverse direction; and frontal, parietal, and temporal bones in the sagittal direction. The least displacement was noted for the occipital bone in all the 3-dimensions. The maximum stresses were concentrated over the region of the lateral margins of the piriform aperture and the medial walls of the orbit. Higher stress values were also found on the parietal bone adjacent to the sagittal suture. The highest value of stresses among the sutures of the craniofacial complex was found to be in the region of the frontonasal, frontomaxillary, and nasomaxillary sutures.
CONCLUSIONS
The effects of displacement and stresses obtained from this study suggest a restriction to the growth of the cranial vault and its normal mobility, in turn altering the intracranial tension and causing altered cranial morphology in young, growing children undergoing high-pull headgear therapy. The human cranial system is dynamic throughout life and may be restricted or altered by hereditary or environmental factors.
Topics: Child; Humans; Child, Preschool; Finite Element Analysis; Computer Simulation; Maxilla; Temporal Bone; Cranial Sutures; Biomechanical Phenomena; Stress, Mechanical
PubMed: 36464568
DOI: 10.1016/j.ajodo.2021.12.020 -
Cirugia Y Cirujanos 2022Depressed skull fractures are the result of trauma injuries. They are present in approximately 3% of patients who arrive to an emergency room with skull trauma. The main...
OBJECTIVE
Depressed skull fractures are the result of trauma injuries. They are present in approximately 3% of patients who arrive to an emergency room with skull trauma. The main objective of surgical repair in depressed fractures is correction of cosmetic deformity and the prevention of infections.
MATERIAL AND METHODS
A retrospective and transversal study was performed by our department between April 2016 and May 2017. Sixteen patients that underwent a craniotomy for skull trauma with depressed fracture were included in the study. The diagnosis was made by simple cranial CT scan alongside a three-dimensional reconstruction.
RESULTS
Of the sixteen patients included, 5 were females (31.2%) and 11 males (68.8%). Twelve of the cases were an exposed fracture. In 7 cases, the fracture was located at parietal bone; 5 were located at frontal bone and 4 at the temporal bone. The average Glasgow coma score in the sample was 13. There were no complications nor deaths.
CONCLUSIONS
The remodeling and repositioning of the autologous bone graft allow an adequate cosmetic result and it also avoids the placement of implants without increasing the costs and additional risks.
Topics: Male; Female; Humans; Skull Fracture, Depressed; Retrospective Studies; Craniotomy; Frontal Bone; Craniocerebral Trauma; Fractures, Bone; Schools
PubMed: 36327480
DOI: 10.24875/CIRU.21000016 -
Development (Cambridge, England) Jan 2022A major feature of Saethre-Chotzen syndrome is coronal craniosynostosis, the fusion of the frontal and parietal bones at the coronal suture. It is caused by heterozygous...
A major feature of Saethre-Chotzen syndrome is coronal craniosynostosis, the fusion of the frontal and parietal bones at the coronal suture. It is caused by heterozygous loss-of-function mutations in either of the bHLH transcription factors TWIST1 and TCF12. Although compound heterozygous Tcf12; Twist1 mice display severe coronal synostosis, the individual role of Tcf12 had remained unexplored. Here, we show that Tcf12 controls several key processes in calvarial development, including the rate of frontal and parietal bone growth, and the boundary between sutural and osteogenic cells. Genetic analysis supports an embryonic requirement for Tcf12 in suture formation, as combined deletion of Tcf12 in embryonic neural crest and mesoderm, but not in postnatal suture mesenchyme, disrupts the coronal suture. We also detected asymmetric distribution of mesenchymal cells on opposing sides of the wild-type frontal and parietal bones, which prefigures later bone overlap at the sutures. In Tcf12 mutants, reduced asymmetry is associated with bones meeting end-on-end, possibly contributing to synostosis. Our results support embryonic requirements of Tcf12 in proper formation of the overlapping coronal suture.
Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Craniosynostoses; Mesenchymal Stem Cells; Mesoderm; Mice; Mice, Inbred C57BL; Neural Crest; Osteogenesis; Skull
PubMed: 34878091
DOI: 10.1242/dev.199575 -
Insights Into Imaging Feb 2020The skull vault, formed by the flat bones of the skull, has a limited spectrum of disease that lies between the fields of neuro- and musculoskeletal radiology. Its...
The skull vault, formed by the flat bones of the skull, has a limited spectrum of disease that lies between the fields of neuro- and musculoskeletal radiology. Its unique abnormalities, as well as other ubiquitous ones, present particular features in this location. Moreover, some benign entities in this region may mimic malignancy if analyzed using classical bone-tumor criteria, and proper patient management requires being familiar with these presentations. This article is structured as a practical review offering a systematic diagnostic approach to focal calvarial lesions, broadly organized into four categories: (1) pseudolesions: arachnoid granulations, meningo-/encephaloceles, vascular canals, frontal hyperostosis, parietal thinning, parietal foramina, and sinus pericrani; (2) lytic: fibrous dysplasia, epidermal inclusion and dermoid cysts, eosinophilic granuloma, hemangioma, aneurysmal bone cyst, giant cell tumor, metastasis, and myeloma; (3) sclerotic: osteomas, osteosarcoma, and metastasis; (4) transdiploic: meningioma, hemangiopericytoma, lymphoma, and metastasis, along with other less common entities. Tips on the potential usefulness of functional imaging techniques such as MR dynamic susceptibility (T2*) perfusion, MR spectroscopy, diffusion-weighted imaging, and PET imaging are provided.
PubMed: 32056014
DOI: 10.1186/s13244-019-0820-9 -
BMC Anesthesiology Dec 2022With recent advances in robot-assisted techniques, an increasing number of surgeries are being performed with pneumoperitoneum and head-down maneuver (HDM) that may...
BACKGROUND
With recent advances in robot-assisted techniques, an increasing number of surgeries are being performed with pneumoperitoneum and head-down maneuver (HDM) that may affect the cerebral microcirculation. For the first time, this study investigated the direct influence of pneumoperitoneum and HDM on the cerebral microvasculature in rabbits.
METHODS
Adult male rabbits were randomly allocated to the following groups (n = 7 each): control, pneumoperitoneum alone (P), and pneumoperitoneum with HDM (P + HDM) for 120 min. A closed cranial window was installed above the parietal bone to visualize the pial microvasculature. Pial arteriolar diameter and hemodynamic and blood gas parameters were measured during the 140-min observation period. Brain edema was assessed by evaluation of the brain water content at the end of the experiment.
RESULTS
Rabbits in the P and P + HDM groups exhibited a similar degree of immediate pial arteriolar dilation following the initiation of both P and P + HDM (P: 1.11 ± 0.03, p = 0.0044 and P + HDM: 1.07 ± 0.02, p = 0.0004, relative changes from the baseline value by defining the baseline as one). In the P + HDM group, pial arteriole diameter returned to the baseline level following the discontinuation of pneumoperitoneum and HDM (1.05 ± 0.03, p = 0.0906, vs. baseline). In contrast, the pial arterioles remained dilated as compared to the baseline level in the P group after discontinuation of pneumoperitoneum. There were no changes in pial arteriole diameter in the animals in the control group. Heart rate, blood gas parameters, and brain water content were not significantly different between the groups.
CONCLUSION
The pial arterioles dilated immediately after pneumoperitoneum with or without HDM. The pial arterioles remained dilated 20 min after discontinuation of pneumoperitoneum alone but constricted upon discontinuation of pneumoperitoneum plus HDM. Pneumoperitoneum and HDM for 2 h did not cause brain edema.
Topics: Male; Animals; Rabbits; Pneumoperitoneum; Brain Edema; Injections, Intraperitoneal; Microvessels; Microcirculation
PubMed: 36457106
DOI: 10.1186/s12871-022-01911-2 -
Current Medical Imaging 2021McCune-Albright Syndrome (MAS) is a genetic disorder with a triad of endocrine diseases, café-au-lait macules and fibrous dysplasias. Craniofacial fibrous dysplasia is... (Review)
Review
BACKGROUND
McCune-Albright Syndrome (MAS) is a genetic disorder with a triad of endocrine diseases, café-au-lait macules and fibrous dysplasias. Craniofacial fibrous dysplasia is a term that is used to describe the fibrous dysplasia, which was localized at the craniofacial skeleton and is common in MAS patients.
OBJECTIVE
The objective of this review is to determine the involvement frequency of cranial and facial bones in patients with MAS and CFD.
METHODS
Articles in PubMed was searched with the following details "(mccune[Title/Abstract] OR albright[Title/Abstract]) OR ("craniofacial fibrous dysplasia"[MeSH Terms] OR ("craniofacial"[ All Fields] AND "fibrous"[All Fields] AND "dysplasia"[All Fields]) OR "craniofacial fibrous dysplasia"[All Fields])". The articles in which the authors did not state the involved bones or did not add any radiographic images were excluded from the study.
RESULTS
26 cases in 25 articles met the inclusion criteria. Among the 26 cases and our case, sphenoid and frontal bones were involved in 17 cases, parietal and occipital bones were involved in 15 cases, mandible and ethmoid bone were involved in 14 cases, maxilla-zygoma-temporal and palate was involved in 13, 11, 6 and 3 cases, respectively. Palate was involved in cases where maxilla was also involved. Our case was the only case that was evaluated with CBCT.
CONCLUSION
Routine follow-ups are important since new CFDs can occur in different cranial or facial bones. 2D imaging techniques may not be able to demonstrate early CFDs; thus, an advanced imaging technique should be used after MAS diagnosis.
Topics: Craniofacial Fibrous Dysplasia; Facial Bones; Fibrous Dysplasia of Bone; Fibrous Dysplasia, Polyostotic; Humans; Sphenoid Bone
PubMed: 33297918
DOI: 10.2174/1573405616666201209102418 -
Journal of Dental Research Jun 2023Retinoid signaling disorders cause craniofacial deformity, among which infants with maternal vitamin A deficiency (VAD) exhibited malformation of the eye, nose, palate,...
Retinoid signaling disorders cause craniofacial deformity, among which infants with maternal vitamin A deficiency (VAD) exhibited malformation of the eye, nose, palate, and parietal and jaw bone. Previous research uncovered the pathogenesis of eye defect and cleft palate of VAD in mice, but the studies on craniofacial skeletal deformity met obstacles, and the cell/lineage and underlying mechanism remain unclear. The retinoic acid receptor (RAR) is the key transcription factor in retinoid signaling, but individual knockout cannot simulate pathway inhibition. Here, we conditionally expressed dominant-negative RARα mutation () in osteoblasts to specifically inhibit the transcription activity of RAR in mice, which mimics the craniofacial deformities caused by VAD in clinical cases: hypomineralization of cranial bones, mandibular deformity, and clavicular hypoplasia. Furthermore, we performed 3-dimensional reconstruction based on micro-computed tomography and confirmed the abnormalities in the shape, size, and ossification of craniofacial bones due to osteoblastic RAR inhibition. Histological analysis indicated that inhibition of RAR in osteoblasts impaired both bone formation and bone resorption, which was confirmed by transcriptome sequencing of the calvaria. Furthermore, mechanism investigation showed that inhibition of RAR in osteoblasts directly decreased osteoblast differentiation in a cell-autonomous manner by impairing osteogenic gene transcription and also inhibited osteoclast differentiation via osteoblast-osteoclast crosstalk by impairing transcription. In summary, osteoblastic RAR activity is critical to craniofacial skeletal development, and its dysfunction leads to skeletal deformities mimicking VAD craniofacial defects, providing a new insight for VAD pathogenesis.
Topics: Mice; Animals; Vitamin A Deficiency; X-Ray Microtomography; Receptors, Retinoic Acid; Skull; Osteoblasts; Retinoids
PubMed: 37036085
DOI: 10.1177/00220345231151691 -
Cellular and Molecular Life Sciences :... Feb 2022Calvarial bone is one of the most complex sequences of developmental events in embryology, featuring a uniquely transient, pluripotent stem cell-like population known as... (Review)
Review
Calvarial bone is one of the most complex sequences of developmental events in embryology, featuring a uniquely transient, pluripotent stem cell-like population known as the cranial neural crest (CNC). The skull is formed through intramembranous ossification with distinct tissue lineages (e.g. neural crest derived frontal bone and mesoderm derived parietal bone). Due to CNC's vast cell fate potential, in response to a series of inductive secreted cues including BMP/TGF-β, Wnt, FGF, Notch, Hedgehog, Hippo and PDGF signaling, CNC enables generations of a diverse spectrum of differentiated cell types in vivo such as osteoblasts and chondrocytes at the craniofacial level. In recent years, since the studies from a genetic mouse model and single-cell sequencing, new discoveries are uncovered upon CNC patterning, differentiation, and the contribution to the development of cranial bones. In this review, we summarized the differences upon the potential gene regulatory network to regulate CNC derived osteogenic potential in mouse and human, and highlighted specific functions of genetic molecules from multiple signaling pathways and the crosstalk, transcription factors and epigenetic factors in orchestrating CNC commitment and differentiation into osteogenic mesenchyme and bone formation. Disorders in gene regulatory network in CNC patterning indicate highly close relevance to clinical birth defects and diseases, providing valuable transgenic mouse models for subsequent discoveries in delineating the underlying molecular mechanisms. We also emphasized the potential regenerative alternative through scientific discoveries from CNC patterning and genetic molecules in interfering with or alleviating clinical disorders or diseases, which will be beneficial for the molecular targets to be integrated for novel therapeutic strategies in the clinic.
Topics: Animals; Bone Morphogenetic Proteins; Cell Differentiation; Gene Regulatory Networks; Mesoderm; Neural Crest; Osteoblasts; Osteogenesis; Signal Transduction; Transforming Growth Factor beta
PubMed: 35220463
DOI: 10.1007/s00018-022-04208-2 -
Brazilian Dental Journal 2021The limited options for bone repair have led to an extensive research of the field and the development of alloplastic and xenogeneic grafts. The purpose of this study...
The limited options for bone repair have led to an extensive research of the field and the development of alloplastic and xenogeneic grafts. The purpose of this study was to evaluate bone repair with two bone substitutes: deproteinized bovine bone (DBB) and biphasic calcium phosphate ceramic (BCP) in critical-size defect. A total of 8-mm defects were made in the parietal bones of rabbits (n=12). The animals were divided into three experimental groups: sham (defect filled with a blood clot), DBB (defect filled with DBB), and BCP (defect filled with BCP). After the experimental periods of 15 and 45 days, the animals were euthanized and submitted to histomorphometric analysis. The total defect area, mineralized tissue area, biomaterial area, and soft tissue area were evaluated. A greater amount of immature bone tissue and biomaterial particles were observed in the BCP group compared to DBB and sham at 45 days (p<0.05). There was no difference in the qualitative pattern of bone deposition between DBB and BCP. However, the sham group did not show osteoid islands along with the defect, presenting a greater amount of collagen fibers as well in relation to the DBB and BCP groups. There was a greater number of inflammatory cells in the DBB at 45 days compared to BCP and sham groups. In conclusion, BCP and DBB are options for optimizing the use of bone grafts for maxillofacial rehabilitation. Bone defects treated with BCP showed greater deposition of bone tissue at 45 days.
Topics: Animals; Bone Matrix; Bone Regeneration; Bone Substitutes; Calcium Phosphates; Cattle; Ceramics; Hydroxyapatites; Osteogenesis; Rabbits
PubMed: 33913998
DOI: 10.1590/0103-6440202103583