Morphometric analysis of untreated adult skulls in syndromic and nonsyndromic craniosynostosis

A novel approach to craniofacial analysis using automated 3D landmarking of the skull

Automatic dense 3D surface registration is a powerful technique for comprehensive 3D shape analysis that has found a successful application in human craniofacial morphology research, particularly within the mandibular and cranial vault regions. However, a notable gap exists when exploring the frontal aspect of the human skull, largely due to the intricate and unique nature of its cranial anatomy. To better examine this region, this study introduces a simplified single-surface craniofacial bone mask comprising of 6707 quasi-landmarks, which can aid in the classification and quantification of variation over human facial bone surfaces. Automatic craniofacial bone phenotyping was conducted on a dataset of 31 skull scans obtained through cone-beam computed tomography (CBCT) imaging. The MeshMonk framework facilitated the non-rigid alignment of the constructed craniofacial bone mask with each individual target mesh. To gauge the accuracy and reliability of this automated process, 20 anatomical facial landmarks were manually placed three times by three independent observers on the same set of images. Intra- and inter-observer error assessments were performed using root mean square (RMS) distances, revealing consistently low scores. Subsequently, the corresponding automatic landmarks were computed and juxtaposed with the manually placed landmarks. The average Euclidean distance between these two landmark sets was 1.5 mm, while centroid sizes exhibited noteworthy similarity. Intraclass coefficients (ICC) demonstrated a high level of concordance (> 0.988), with automatic landmarking showing significantly lower errors and variation. These results underscore the utility of this newly developed single-surface craniofacial bone mask, in conjunction with the MeshMonk framework, as a highly accurate and reliable method for automated phenotyping of the facial region of human skulls from CBCT and CT imagery. This craniofacial template bone mask expansion of the MeshMonk toolbox not only enhances our capacity to study craniofacial bone variation but also holds significant potential for shedding light on the genetic, developmental, and evolutionary underpinnings of the overall human craniofacial structure.

Automated 3D Landmarking of the Skull: A Novel Approach for Craniofacial Analysis

Automatic dense 3D surface registration is a powerful technique for comprehensive 3D shape analysis that has found a successful application in human craniofacial morphology research, particularly within the mandibular and cranial vault regions. However, a notable gap exists when exploring the frontal aspect of the human skull, largely due to the intricate and unique nature of its cranial anatomy. To better examine this region, this study introduces a simplified single-surface craniofacial bone mask comprising 9,999 quasi-landmarks, which can aid in the classification and quantification of variation over human facial bone surfaces. Automatic craniofacial bone phenotyping was conducted on a dataset of 31 skull scans obtained through cone-beam computed tomography (CBCT) imaging. The MeshMonk framework facilitated the non-rigid alignment of the constructed craniofacial bone mask with each individual target mesh. To gauge the accuracy and reliability of this automated process, 20 anatomical facial landmarks were manually placed three times by three independent observers on the same set of images. Intra- and inter-observer error assessments were performed using root mean square (RMS) distances, revealing consistently low scores. Subsequently, the corresponding automatic landmarks were computed and juxtaposed with the manually placed landmarks. The average Euclidean distance between these two landmark sets was 1.5mm, while centroid sizes exhibited noteworthy similarity. Intraclass coefficients (ICC) demonstrated a high level of concordance (>0.988), and automatic landmarking showing significantly lower errors and variation. These results underscore the utility of this newly developed single-surface craniofacial bone mask, in conjunction with the MeshMonk framework, as a highly accurate and reliable method for automated phenotyping of the facial region of human skulls from CBCT and CT imagery. This craniofacial template bone mask expansion of the MeshMonk toolbox not only enhances our capacity to study craniofacial bone variation but also holds significant potential for shedding light on the genetic, developmental, and evolutionary underpinnings of the overall human craniofacial structure.

A rare case of the scaphocephalic skull of an adult male

Background

Scaphocephaly is a craniofacial anomaly where the skull is disproportionately long and narrow. Premature closure of the sagittal suture is thought to be at the core of the etiopathology for scaphocephaly.

Case presentation

The skull is a well-preserved skull found in an antiquated graveyard at Parkand village Daregaz, Iran, with no visible signs of surgical manipulation. The craniofacial indices were measured. The maximum cranial length was 200 mm, and the measured length of nasion-bregma was 140mm, whereas most of the measurements were less than the normal scaphocephalic indices. Another morphological finding was the flattening of the frontal bone.

Conclusions

The cranial vault morphometry and morphology of the presented case fit the scalp. In addition to the characteristics of scaphocephaly, the presented skull was of a rare trait, frontal flattening, which has not been reported before.

Diploic vein morphology in normal and craniosynostotic adult human skulls

Diploic veins (DV) run within the cranial diploe, where they leave channels that can be studied in osteological samples. This study investigates overall DV variability in human adults and the effects of sex, age, cranial dimensions, and dysmorphogenesis associated with craniosynostosis (CS). The morphology of macroscopic diploic channels was analyzed in a set of the qualitative and quantitative variables in computed tomography-images of crania of anatomically normal and craniosynostotic adult individuals. Macroscopic diploic channels occur most frequently in the frontal and parietal bones, often with a bilaterally symmetrical pattern. DV-features (especially DV-pattern) are characterized by high individual diversity. On average, there are 5.4 ± 3.5 large macroscopic channels (with diameters >1 mm) per individual, with a mean diameter of 1.7 ± 0.4 mm. Age and sex have minor effects on DV, and cranial proportions significantly influence DV only in CS skulls. CS is associated with changes in the DV numbers, distributions, and diameters. Craniosynostotic skulls, especially brachycephalic skulls, generally present smaller DV diameters, and dolichocephalic skulls display increased number of frontal DV. CS, associated with altered cranial dimensions, suture imbalance, increased intracranial pressure, and with changes of the endocranial craniovascular system, significantly also affects the macroscopic morphology of DV in adults, in terms of both structural (topological redistribution) and functional factors. The research on craniovascular morphology and CS may be of interest in biological anthropology, paleopathology, medicine (e.g., surgical planning), but also in zoology and paleontology.

Craniovascular traits and braincase morphology in craniosynostotic human skulls

Middle meningeal vessels, dural venous sinuses, and emissary veins leave imprints and canals in the endocranium, and thus provide evidence of vascular patterns in osteological samples. This paper investigates whether craniovascular morphology undergoes changes in craniosynostotic human skulls, and if specific alterations may reflect structural and functional relationships in the cranium. The analyzed osteological sample consists of adult individuals with craniosynostoses generally associated with dolichocephalic or brachycephalic proportions, and a control sample of anatomically normal adult skulls. The pattern and dominance of the middle meningeal artery, the morphology of the confluence of the sinuses, and the size and number of the emissary foramina were evaluated. Craniovascular morphology was more diverse in craniosynostotic skulls than in anatomically normal skulls. The craniosynostotic skulls often displayed enlarged occipito-marginal sinuses and more numerous emissary foramina. The craniosynostotic skulls associated with more brachycephalic morphology often presented enlarged emissary foramina, while the craniosynostotic skulls associated with dolichocephalic effects frequently displayed more developed posterior branches of the middle meningeal artery. The course and morphology of the middle meningeal vessels, dural venous sinuses, and emissary veins in craniosynostotic skulls can be related to the redistribution of growth forces, higher intracranial pressure, venous hypertension, or thermal constraints. These functional and structural changes are of interest in both anthropology and medicine, involving epigenetic traits that concern the functional and ontogenetic balance between soft and hard tissues.

Objective Analysis of Fronto-Orbital Dysmorphology in Unilateral Coronal Craniosynostosis

ABSTRACT

Correction (and over-correction) of asymmetries of the orbital shape and brow position in unilateral coronal craniosynostosis (UCS) is critical to successful fronto-orbital advancement. Here we quantify and three-dimensionally assess fronto-orbital irregularities in UCS patients compared to controls.Twenty-three patients with UCS evaluated at the Children's Hospital of Pittsburgh between 2006 and 2016 were age and gender-matched to controls. Computed tomography scans were reconstructed and evaluated for orbital metrics. A three-dimensional heat map of orbital regions was generated and evaluated for shape differences.Brow protrusion of the orbit ipsilateral to the synostotic suture did not differ significantly from healthy controls. Orbital height was significantly increased while orbital width was decreased on the UCS ipsilateral side compared to the contralateral side and controls. The ipsilateral cornea was overprojected relative to the brow and the infraorbital rim, but similar to controls relative to the lateral rim. The contralateral orbit had increased brow protrusion with decreased orbital height. The cornea was underprojected relative to the brow, but overprojected relative to the lateral orbital rim and similar to controls at the infraorbital rim. Three-dimensional comparison demonstrated significant overprojection of the contralateral brow, with some more mild and inconsistent underprojection of the lateral aspect of the ipsilateral brow.Key orbital and brow differences exist between the affected and unaffected sides in UCS. This study provides quantitative data that further characterize the orbital dysmorphology observed in UCS and identifies unique aspects of the diagnosis that should be taken into consideration during surgical planning.

Craniofacial shape in patients with beta thalassaemia: a geometric morphometric analysis

The shape of the craniofacial complex of patients with beta thalassaemia was evaluated using geometric morphometrics on lateral cephalometric radiographs and was compared with matched controls. The beta thalassaemia group consisted of 40 patients (16 females, 24 males, mean age 33.4). Each patient was matched by age and gender to two controls (32 females, 48 males, mean age 33.1). The 120 lateral cephalometric radiographs were digitized and traced with 15 curves, 10 landmarks and 117 sliding semi-landmarks. These landmarks were subjected to Procrustes superimposition and principal component analysis in order to describe shape variability of the cranial base, maxilla and mandible, as well as of the entire craniofacial complex for each sex. The first 4 principal components accounted for 50% of the total sample's variability. The beta thalassaemia group was significantly different in overall shape to the control group for both sexes. Similar findings were noted for the maxilla, the mandible and the cranial base. The main differences were related to smaller mandibular body for the thalassaemia group, midface protrusion and decrease in posterior face height. The shape of the craniofacial complex in these patients is prone to be more convex and hyperdivergent.

Squamous suture obliteration: frequency and investigation of the associated skull morphology

This study aimed to investigate the frequency of squamous suture (SqS) obliteration, to estimate the involvement of the major calvarial sutures and those surrounding the temporal squama, and to inspect the neuro- and basicranium for deformities. A series of 211 dry skulls of contemporary adult males were macroscopically observed. The skulls with closed SqS were scanned using an industrial µCT system. Digital morphometry of the skulls with obliterated SqS was performed by recording the 3D coordinates of anatomic landmarks and calculation of linear distances, angles and indices. Obliteration of SqS was observed in 3 (1.42%) skulls. One skull showed bilateral SqS obliteration. The other two cases were unilateral, one right-sided and one left-sided. SqS obliteration seems to be co-ordinated with the closure of the parietomastoid suture, partially related to the closure of the occipitomastoid, sphenoparietal and sphenofrontal sutures, and independent from the closure of the sphenosquamosal suture and the major calvarial sutures. No severe disproportions in the skull configuration were observed in the three investigated cases. The major differences in the complimentary hemicrania concern the parietal and occipital parts of the skull vault. Dorsum sellae erosion, an indicator for raised intracranial pressure, was observed in all three cases.

Early Surgical Treatment in Anterior Synostotic Plagiocephaly: Is This the Best Choice?

At the end of craniofacial growth, in anterior synostotic plagiocephaly, some aesthetical deficiencies may still be evident. This can depend on an inadequate initial correction or on altered postoperative growth or even on the combination of the 2 factors.Aesthetic alterations can result from various factors that could potentially affect the skeleton, the skin, subcutaneous, and muscular tissues.The pathological changes in the cutaneous and subcutaneous tissues are greater in patients who have undergone multiple surgical treatments of the frontoorbital area. The aim of this observational cohort study is to assess the residual aesthetic and functional impairment at the end of skeletal growth, in patients affected by anterior synostotic plagiocephaly who have undergone surgery at an early age. The purpose is to investigate whether early surgery can still be considered unavoidable in patients with this malformation.Between July 2012 and February 2015, patient's data were retrieved from our archives among the patients referred to our department from 2003 to 2012 for Anterior Synostotic Plagiocephaly at an early age.The authors studied this patient with CT scans and photographic documentation. On CT scans, the authors have assessed skeletal alterations, soft tissues alterations, and muscular tissue alterations. With photographic documentation, the authors have studied the perception of the malformation among external subjects.From this study it was possible to demonstrate that is many esthetical alterations are to still to be found in patients treated with an early surgical approach; for this reason in children without early complications, the authors suggest that surgical treatment should be delayed after the end of craniofacial growth.

Intracranial Venous Hypertension in Craniosynostosis: Mechanistic Underpinnings and Therapeutic Implications

Patients with complex, multisutural, and syndromic craniosynostosis (CSO) frequently exhibit intracranial hypertension. The intracranial hypertension cannot be entirely attributed to the craniocephalic disproportion with calvarial restriction because cranial vault expansion has not consistently alleviated elevated intracranial pressure. Evidence has most strongly supported a multifactorial interaction, including venous hypertension along with other pathogenic processes. Patients with CSO exhibit marked venous anomalies, including stenosis of the jugular-sigmoid complex, transverse sinuses, and extensive transosseous venous collaterals. These abnormal intracranial-extracranial occipital venous collaterals might represent anomalous development, with persistence and subsequent enlargement of channels normally present in the fetus, either as a primary defect or as nonregression in response to failure of the development of the jugular-sigmoid complexes. It has been suggested by some investigators that venous hypertension in patients with CSO could be treated directly via jugular foraminoplasty, venous stenting, or jugular venous bypass, although these options are not in common clinical practice. Obstructive sleep apnea, occurring as a consequence of midface hypoplasia, can also contribute to intracranial hypertension in patients with syndromic CSO. Thus, correction of facial deformities, as well as posterior fossa decompression, could also play important roles in the treatment of intracranial hypertension. Determining the precise mechanistic underpinnings underlying intracranial hypertension in any given patient with CSO requires individualized evaluation and management.

Fronto-ethmoidal encephalocele in a historical skull with artificial deformation and no signs of chronic elevated intracranial pressure

The intentional deformation of human skulls in the living being was one of the most curious rituals performed in historical and ancient times. It is thought that these practices cause chronic elevated intracranial pressure and subsequent symptoms of cognitive impairment. In this report, we examine such an artificially deformed skull dating from the sixteenth century that in addition shows a fronto-ethmoidal encephalocele. However, although the mild encephalocele was already manifest at birth and deformation practices were performed over years, the encephalocele did not progress into a more severe status. We conclude that the intentional deformation of skulls does not lead to chronic elevated intracranial pressure and mental retardation.

Detecting an undiagnosed case of nonsyndromic facial dysmorphism using geometric morphometrics

The Johns Hopkins University Center for Craniofacial Development and Disorders estimates that 1 in 3,000 children born in the United States is diagnosed with a rare form of craniosynostosis. Although the medical literature has documented numerous descriptions of craniofacial disorders from an anthropometric or genetic perspective, considerably fewer reports of these anomalies have been documented in the context of forensic anthropology. Similar genetic origins of many craniofacial anomalies generate ranges of phenotypic variation between and even within documented cases, producing difficulties in acquiring correct diagnoses. Identical physical characteristics manifested in different disorders create further complications in identifying a craniofacial syndrome in skeletal remains. Reported here is an unusual case of a possibly undiagnosed craniofacial abnormality in a set of identified skeletal remains from a North Carolina homicide case. Traditional metric and geometric morphometric approaches were utilized to further investigate morphological shape differences between the case study and a reference sample. Results show significant differences suggesting a nonsyndromic form of craniosynostosis.