Craniosynostosis

Neuroimaging in Nonsyndromic Craniosynostosis: Key Concepts to Unlock Innovation

Craniosynostoses (CRS) are caused by the premature fusion of one or more cranial sutures, with isolated nonsyndromic CRS accounting for most of the clinical manifestations. Such premature suture fusion impacts both skull and brain morphology and involves regions far beyond the immediate area of fusion. The combined use of different neuroimaging tools allows for an accurate depiction of the most prominent clinical-radiological features in nonsyndromic CRS but can also contribute to a deeper investigation of more subtle alterations in the underlying nervous tissue organization that may impact normal brain development. This review paper aims to provide a comprehensive framework for a better understanding of the present and future potential applications of neuroimaging techniques for evaluating nonsyndromic CRS, highlighting strategies for optimizing their use in clinical practice and offering an overview of the most relevant technological advancements in terms of diagnostic performance, radiation exposure, and cost-effectiveness.

Machine learning applications in craniosynostosis diagnosis and treatment prediction: a systematic review

Craniosynostosis refers to the premature fusion of one or more of the fibrous cranial sutures connecting the bones of the skull. Machine learning (ML) is an emerging technology and its application to craniosynostosis detection and management is underexplored. This systematic review aims to evaluate the application of ML techniques in the diagnosis, severity assessment, and predictive modeling of craniosynostosis. A comprehensive search was conducted on the PubMed and Google Scholar databases using predefined keywords related to craniosynostosis and ML. Inclusion criteria encompassed peer-reviewed studies in English that investigated ML algorithms in craniosynostosis diagnosis, severity assessment, or treatment outcome prediction. Three independent reviewers screened the search results, performed full-text assessments, and extracted data from selected studies using a standardized form. Thirteen studies met the inclusion criteria and were included in the review. Of the thirteen papers examined on the application of ML to the identification and treatment of craniosynostosis, two papers were dedicated to sagittal craniosynostosis, five papers utilized several different types of craniosynostosis in the training and testing of their ML models, and six papers were dedicated to metopic craniosynostosis. ML models demonstrated high accuracy in identifying different types of craniosynostosis and objectively quantifying severity using innovative metrics such as metopic severity score and cranial morphology deviation. The findings highlight the significant strides made in utilizing ML techniques for craniosynostosis diagnosis, severity assessment, and predictive modeling. Predictive modeling of treatment outcomes following surgical interventions showed promising results, aiding in personalized treatment strategies. Despite methodological diversities among studies, the collective evidence underscores ML's transformative potential in revolutionizing craniosynostosis management.

Experiences of surgical complications and reoperations in nonsyndromic sagittal synostosis patients in Oulu

OBJECTIVE

The purpose of this study was to evaluate the surgical complications of patients treated for nonsyndromic sagittal craniosynostosis and the necessity for reoperations due to craniocerebral disproportion.

MATERIALS AND METHODS

The patient cohort of this study consisted of patients (N = 82) who were treated in the Oulu University Hospital using the open vault cranioplasty with a modified H-technique between the years 2008 to 2022. There were 69 males (84.1%) and 13 females (15.9%). The mean age at the primary operation was 6.1 months. Mean follow-up time was 9.0 years.

RESULTS

There were no major complications related to the procedures. Two patients (2.4%) had a minor dural lesion. There were no postoperative wound infections. Of the 82 patients, seven patients with primary craniosynostosis (13.0%) developed symptomatic craniocerebral disproportion requiring reoperation to increase intracranial volume. In all these patients, invasive intracranial pressure (ICP) monitoring was performed prior to decision-making. In the majority of cases, the aesthetical outcome was considered good or excellent.

CONCLUSION

The operative method used was feasible and safe. Thirteen percent of patients who were followed over 5 years required major surgery due to development of craniocerebral disproportion later in life.

Resorbable Patient-Specific Implants of Molybdenum for Pediatric Craniofacial Surgery-Proof of Concept in an In Vivo Pilot Study

Titanium continues to be the gold standard in the field of osteosynthesis materials. This also applies to pediatric craniofacial surgery. Various resorbable materials have already been developed in order to avoid costly and risky second operations to remove metal in children. However, none of these resorbable materials have been able to completely replace the previous gold standard, titanium, in a satisfactory manner. This has led to the need for a new resorbable osteosynthesis material that fulfills the requirements for biocompatibility, stability, and uniform resorption. In our previous in vitro and in vivo work, we were able to show that molybdenum fulfills these requirements. To further confirm these results, we conducted a proof of concept in four domestic pigs, each of which was implanted with a resorbable molybdenum implant. The animals were then examined daily for local inflammatory parameters. After 54 days, the animals were euthanized with subsequent computer tomography imaging. We also removed the implants together with the surrounding tissue and parts of the spleen, liver, and kidney for histopathological evaluation. The molybdenum implants were also analyzed metallographically and using scanning electron microscopy. A blood sample was taken pre- and post-operatively. None of the animals showed clinical signs of inflammation over the entire test period. Histopathologically, good tissue compatibility was found. Early signs of degradation were observed after 54 days, which were not sufficient for major resorption. Resorption is expected with longer in situ residence times based on results of similar earlier investigations.

Management of Craniosynostosis in Lethal Perinatal Hypophosphatasia

Although perinatal lethal hypophosphatasia (HPP) was once a disease with a universally poor prognosis, it has now become a rare but treatable condition with the advent of enzyme replacement therapy with asfotase alfa. As a result, a greater population of patients with perinatal HPP are presenting with abnormal head shape and craniosynostosis. The authors present here 3 cases of perinatal lethal HPP, 1 treated with traditional open cranial vault remodeling and 2 treated utilizing distraction osteogenesis techniques. All patients demonstrated outcomes comparable to those previously reported with traditional observation or open cranial vault repair. Thorough consideration and discussion between the surgical team and patient's family is needed to determine a treatment plan that best addresses the goals of patient and family in light of recent advances in medical treatment in this rare patient population in which surgical interventions were previously nearly impossible. This article further supports the safety and efficacy of surgical intervention and explores the utility of distraction osteogenesis to address craniosynostosis in this patient population.

3D-2D Distance Maps Conversion Enhances Classification of Craniosynostosis

OBJECTIVE

Diagnosis of craniosynostosis using photogrammetric 3D surface scans is a promising radiation-free alternative to traditional computed tomography. We propose a 3D surface scan to 2D distance map conversion enabling the usage of the first convolutional neural networks (CNNs)-based classification of craniosynostosis. Benefits of using 2D images include preserving patient anonymity, enabling data augmentation during training, and a strong under-sampling of the 3D surface with good classification performance.

METHODS

The proposed distance maps sample 2D images from 3D surface scans using a coordinate transformation, ray casting, and distance extraction. We introduce a CNN-based classification pipeline and compare our classifier to alternative approaches on a dataset of 496 patients. We investigate into low-resolution sampling, data augmentation, and attribution mapping.

RESULTS

Resnet18 outperformed alternative classifiers on our dataset with an F1-score of 0.964 and an accuracy of 98.4%. Data augmentation on 2D distance maps increased performance for all classifiers. Under-sampling allowed 256-fold computation reduction during ray casting while retaining an F1-score of 0.92. Attribution maps showed high amplitudes on the frontal head.

CONCLUSION

We demonstrated a versatile mapping approach to extract a 2D distance map from the 3D head geometry increasing classification performance, enabling data augmentation during training on 2D distance maps, and the usage of CNNs. We found that low-resolution images were sufficient for a good classification performance.

SIGNIFICANCE

Photogrammetric surface scans are a suitable craniosynostosis diagnosis tool for clinical practice. Domain transfer to computed tomography seems likely and can further contribute to reducing ionizing radiation exposure for infants.

Craniometric and Aesthetic Outcomes in Craniosynostosis Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

To systematically review the published comparative aesthetic outcomes, and its determinants, for craniosynostoses surgically treated by minimally-invasive cranial procedures and open cranial vault remodeling (CVR).

DESIGN

PRISMA-compliant systematic review.

SETTING

Not-applicable.

PATIENTS/PARTICIPANTS

Articles were included if they compared spring cranioplasty, strip minimally-invasive craniectomy or CVR for outcomes related to aesthetics or head shape. Forty-two studies were included, comprising 2402 patients.

INTERVENTIONS

None.

MAIN OUTCOME MEASURE(S)

The craniometric and PROM used to determine surgical outcomes.

RESULTS

Twenty-five studies (59%) evaluated sagittal craniosynostosis, with metopic (7;17%) and unicoronal (4;10%) the next most prevalent. Thirty-eight studies (90%) included CVR, 24 (57%) included strip craniectomy with helmeting, 9 (22%) included strip craniectomy without helmeting, 11 (26%) included spring cranioplasty, and 3 (7%) included vault distraction. A majority of studies only used 1 (43%) or 2 (14%) craniometric measures to compare techniques. In sagittal synostosis, 13 (59%) studies showed no difference in craniometric outcomes, 5 (23%) showed better results with CVR, 3 (14%) with strip craniectomy, and 1 (5%) with springs. In studies describing other synostoses, 10/14 (71%) were equivocal. Subjective outcome measures followed similar trends. Meta-analysis shows no significant difference in cranial index (CI) outcomes between CVR and less invasive procedures in patients with sagittal synostosis.

CONCLUSIONS

There is no difference in CI outcomes between CVR and less invasive procedures. The majority of literature comparing craniometric and aesthetic outcomes between CVR and less invasive procedures shows equivocal results for sagittal synostosis. However, the heterogeneity of data for other craniosynostoses did not allow meta-analysis.

Ultrasonography as first line imaging for the diagnosis of positional plagiocephaly

BACKGROUND

In the last years, numerous studies evaluated different tools for the diagnosis of positional plagiocephaly (PP). The purpose of this study was to evaluate ultrasonography (US) as a first line screening test of lambdoid sutural patency in child with PP and to compare our results with the literature.

METHODS

All consecutive patients who referred to our Institute from January 2016 to October 2017 with the suspicion of PP, were included in the study and performed US examination of the lambdoid sutures. A 3-6-month clinical follow-up was performed by a pediatric neurosurgeon or a pediatrician to confirm the diagnosis of PP.

RESULTS

Thirty-five children performed US examination and in all cases the diagnosis of PP was confirmed. No cases of anticipated suture fusion were examined during this period. The concordance between US findings and clinical exam follow-up was 100%.

CONCLUSIONS

Ultrasonography of the lambdoid sutures represents an ideal first-line screening test and reliable alternative to other diagnostic techniques for lambdoid sutural patency in child with PP, being radiation free, fast and cheap.

Correlation Between Demographic Variables and Complications in Nonsyndromic Craniosynostosis

PURPOSE

This retrospective cross-sectional, observational study aims to determine the correlation between demographic variables and nonsyndromic craniosynostosis.

METHODS

A cross-sectional study was carried out. The inclusion criteria were nonsyndromic craniosynostosis and the exclusion criteria were patients who did not have complete records.

RESULTS

The sample included 49 patients and mainly women. Patients with more than 4 days in the intensive care unit were related with more complications. Intracranial Hypertension was seen predominantly in patients between 6 and 8 months P =0007.

CONCLUSION

Some variables can modificate complications risk but future studies are needed to further investigate the influence of such variables on craniofacial care.

A Radiation-Free Classification Pipeline for Craniosynostosis Using Statistical Shape Modeling

Background: Craniosynostosis is a condition caused by the premature fusion of skull sutures, leading to irregular growth patterns of the head. Three-dimensional photogrammetry is a radiation-free alternative to the diagnosis using computed tomography. While statistical shape models have been proposed to quantify head shape, no shape-model-based classification approach has been presented yet. Methods: We present a classification pipeline that enables an automated diagnosis of three types of craniosynostosis. The pipeline is based on a statistical shape model built from photogrammetric surface scans. We made the model and pathology-specific submodels publicly available, making it the first publicly available craniosynostosis-related head model, as well as the first focusing on infants younger than 1.5 years. To the best of our knowledge, we performed the largest classification study for craniosynostosis to date. Results: Our classification approach yields an accuracy of 97.8 %, comparable to other state-of-the-art methods using both computed tomography scans and stereophotogrammetry. Regarding the statistical shape model, we demonstrate that our model performs similar to other statistical shape models of the human head. Conclusion: We present a state-of-the-art shape-model-based classification approach for a radiation-free diagnosis of craniosynostosis. Our publicly available shape model enables the assessment of craniosynostosis on realistic and synthetic data.

Novel Screening and Monitoring Techniques for Deformational Plagiocephaly: A Systematic Review

This article summarizes the current state of diagnostic modalities for infant craniofacial deformities and highlights capable diagnostic tools available currently to pediatricians.

Preoperative imaging patterns and intracranial findings in single-suture craniosynostosis: a study from the Synostosis Research Group

OBJECTIVE

The diagnosis of single-suture craniosynostosis can be made by physical examination, but the use of confirmatory imaging is common practice. The authors sought to investigate preoperative imaging use and to describe intracranial findings in children with single-suture synostosis from a large, prospective multicenter cohort.

METHODS

In this study from the Synostosis Research Group, the study population included children with clinically diagnosed single-suture synostosis between March 1, 2017, and October 31, 2020, at 5 institutions. The primary analysis correlated the clinical diagnosis and imaging diagnosis; secondary outcomes included intracranial findings by pathological suture type.

RESULTS

A total of 403 children (67% male) were identified with single-suture synostosis. Sagittal (n = 267), metopic (n = 77), coronal (n = 52), and lambdoid (n = 7) synostoses were reported; the most common presentation was abnormal head shape (97%), followed by a palpable or visible ridge (37%). Preoperative cranial imaging was performed in 90% of children; findings on 97% of these imaging studies matched the initial clinical diagnosis. Thirty-one additional fused sutures were identified in 18 children (5%) that differed from the clinical diagnosis. The most commonly used imaging modality by far was CT (n = 360), followed by radiography (n = 9) and MRI (n = 7). Most preoperative imaging was ordered as part of a protocolized pathway (67%); some images were obtained as a result of a nondiagnostic clinical examination (5.2%). Of the 360 patients who had CT imaging, 150 underwent total cranial vault surgery and 210 underwent strip craniectomy. The imaging findings influenced the surgical treatment 0.95% of the time. Among the 24% of children with additional (nonsynostosis) abnormal findings on CT, only 3.5% required further monitoring.

CONCLUSIONS

The authors found that a clinical diagnosis of single-suture craniosynostosis and the findings on CT were the same with rare exceptions. CT imaging very rarely altered the surgical treatment of children with single-suture synostosis.

Premature Fusion of the Sagittal Suture as an Incidental Radiographic Finding in Young Children

BACKGROUND

Craniosynostosis typically develops prenatally and creates characteristic changes in craniofacial form. Nevertheless, postnatal forms of craniosynostosis have been described. The purpose of this study was to determine the prevalence of incidentally identified, but temporally premature, cranial suture fusion in normocephalic children.

METHODS

Computed tomographic scans obtained from children aged 1 to 5 years evaluated in the authors' emergency department between 2005 and 2016 were reviewed for evidence of craniosynostosis. Patients with prior ventriculoperitoneal shunt, brain or cranial abnormality, or known syndromes were excluded. The presence of craniosynostosis and cranial index was assessed by a panel of three craniofacial surgeons and one pediatric neurosurgeon. Demographic information, fusion type, reason for the computed tomographic scan, and medical history were recorded as covariates. Cranial shape and intracranial volume were calculated using previously validated automated system.

RESULTS

Three hundred thirty-one patients met the inclusion criteria. The mean age was 2.4 ± 1.3 years. Eleven patients (3.3 percent) were found to have a complete (n = 9) or partial (n = 2) fusion of the sagittal suture. All patients had a normal cranial index (0.80; range, 0.72 to 0.87) and a grossly normal head shape. Only two fusions (18.2 percent) were documented by the radiologist. Cranial shape analysis performed in five of the 11 patients showed subtle phenotypic changes along the scaphocephaly spectrum in four patients, with a normal shape in the remaining case.

CONCLUSIONS

Sagittal fusion is present in 3.3 percent of otherwise phenotypically normal children aged 1 to 5 years. The clinical significance of this result is unclear, but routine screening of affected patients is paramount.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, IV.

Optic Canal Analysis in Syndromic Craniosynostosis: Volumetric and Surface Area Validation Study Using Different Measurement Modalities

BACKGROUND

In syndromic craniosynostosis (SC), unlike persistent corneal irritation due to severe exophthalmos and increased intracranial pressure, optic canal (OC) stenosis has been scarcely reported to cause visual impairment. This study aimed to validate the OC volumetric and surface area measurement among SC patients.

METHODS

Sixteen computed tomography scan of SC patients (8 months-6 years old) were imported to Materialise Interactive Medical Image Control System (MIMICS) and Materialise 3-matics software. Three-dimensional (3D) OC models were fabricated, and linear measurements were obtained. Mathematical formulas were used for calculation of OC volume and surface area from the 3D model. The same measurements were obtained from the software and used as ground truth. Data normality was investigated before statistical analyses were performed. Wilcoxon test was used to validate differences of OC volume and surface area between 3D model and software.

RESULTS

The mean values for OC surface area for 3D model and MIMICS software were 103.19 mm2 and 31.27 mm2, respectively, whereas the mean for OC volume for 3D model and MIMICS software were 184.37 mm2 and 147.07 mm2, respectively. Significant difference was found between OC volume (P = 0.0681) and surface area (P = 0.0002) between 3D model and software.

CONCLUSION

Optic canal in SC is not a perfect conical frustum thus making 3D model measurement and mathematical formula for surface area and volume estimation not ideal. Computer software remains the best modality to gauge dimensional parameter and is useful to elucidates the relationship of OC and eye function as well as aiding intervention in SC patients.

Public Perception of a Normal Head Shape in Children With Sagittal Craniosynostosis

: A question that remains unanswered is at what level of surgical correction does the public perceive a head shape to be "normal" or "acceptable?" For most cases of non-syndromic asymptomatic craniosynostosis, the parents desire for surgical correction is to improve the cosmetic appearance of head shape. At the time of this writing, the intraoperative surgeons' perspective of what constitutes an acceptable head shape is the target for surgical correction. In introducing an improved objectively cosmetic goal, an appropriate outcome measure would be to assess what the general public considers a normal or acceptable head shape in children with craniosynostosis.

METHOD

Twenty-two unique images were presented via an online crowdsourcing survey of a severe case of non-syndromic sagittal craniosynosis gradually corrected to an age and gender matched normalized head shape. Participants were recruited via the Sick Kids Twitter account. Participants were invited to rate the head shapes as "normal" or "abnormal."

RESULTS

The 538 participants completed the online survey. Participants were able to reliably and consistently identify normal and abnormal head shapes with a Kappa Score >0.775. Furthermore, participants indicated that a correction of 70% is required in order for the cranial deformity to be regarded as "normal." This threshold closely reflects a normal Cranial Index, which is a widely used morphometric outcome in craniosynostosis.

CONCLUSION

Crowdsourcing provides an ideal method for capturing the general population's perspective on what constitutes a normal and acceptable head shape in children with sagittal craniosynostosis. Laypersons are able to reliably and consistently distinguish cranial deformities from a "normal" head shape. The public indicates a threshold correction of 70% in sagittal craniosynosis to regard it as a "normal" head shape.

Volumetric interpolation of tomographic sequences for accurate 3D reconstruction of anatomical parts

BACKGROUND AND OBJECTIVE

Tomographic sequences of biomedical images are commonly used to achieve a three-dimensional visualization of the human anatomy. In some cases, the number of images contained in the sequence is limited, e.g., in low-dose computed tomography acquired on neonatal patients, resulting in a coarse and inaccurate 3D reconstruction.

METHODS

In this paper, volumetric image interpolation methods, devised to increase the axial resolution of tomographic sequences and achieve a refined 3D reconstruction, are proposed and compared. The techniques taken into consideration are based on motion-compensated frame-interpolation concepts, which have been developed for video applications, mainly frame-rate conversion.

RESULTS

The performance of the proposed methods is quantitatively assessed by using sequences with a simulated low axial resolution obtained from the decimation of standard high-resolution computed tomography sequences. Real data with an actual low axial resolution have been used as well for a qualitative evaluation of the proposed methods.

CONCLUSIONS

The experimental results demonstrate that the proposed methods enable an effective slice interpolation and that the achievable 3D models clearly benefit from the increased axial resolution.

Partial Suture Fusion in Nonsyndromic Single-Suture Craniosynostosis

INTRODUCTION

Partial synostosis of cranial sutures has been shown to have clinical and diagnostic significance. However, there is limited published information about how suture fusion progresses over time. In this study, we evaluate patients with nonsyndromic single-suture synostosis. We aim to define the incidence of partial versus complete suture fusion and whether a correlation exists between the degree of suture fusion and age.

METHODS

Two hundred fifty-four patients with nonsyndromic single-suture synostosis were evaluated. Preoperative computed tomography (CT) scans were rendered in 3-dimensions, all sutures were visualized and assessed for patency or fusion, and length of fusion was measured. Findings were grouped according to suture type (sagittal, coronal, metopic, or lambdoid), the degree of fusion (full, >50%, or <50%), and patient age at time of CT scan (0-90, 91-180, 181-360, or >360 days). Data were analyzed to correlate patient age versus the degree of suture fusion.

RESULTS

For all patients, 72% had complete and 28% had partial synostosis. Ratios of full to partial fusion for each suture type were as follows: sagittal 97:36, coronal 35:22, metopic 46:4, and lambdoid 4:10. The sagittal, coronal, and metopic groups demonstrated greater probabilities of complete suture fusion as patient age increases (P = .021, P < .001, P = .001, respectively). This trend was also noted when all sutures were considered together by age-group (P < .001).

CONCLUSION

We note a partial suture fusion rate of 28.3%. Our analysis shows a correlation between the extent of suture synostosis and patient age. Finally, we demonstrate that different sutures display different patterns of partial and complete fusion.

Imaging in craniosynostosis: when and what?

PURPOSE

Currently, the interest on craniosynostosis in the clinical practice is raised by their increased frequency and their genetic implications other than by the still existing search of less invasive surgical techniques. These reasons, together with the problem of legal issues, make the need of a definite diagnosis for a crucial problem, even in single-suture craniosynostosis (SSC). Although the diagnosis of craniosynostosis is primarily the result of physical examination, craniometrics measuring, and observation of the skull deformity, the radiological assessment currently plays an important role in the confirmation of the diagnosis, the surgical planning, and even the postoperative follow-up. On the other hand, in infants, the use of radiation or the need of sedation/anesthesia raises the problem to reduce them to minimum to preserve such a delicate category of patient from their adverse effects.

METHODS, RESULTS AND CONCLUSIONS

This review aims at summarizing the state of the art of the role of radiology in craniosynostosis, mainly focusing on indications and techniques, to provide an update not only to pediatric neurosurgeons or maxillofacial surgeons but also to all the other specialists involved in their management, like neonatologists, pediatricians, clinical geneticists, and pediatric neurologists.

Recent Advances in Craniosynostosis

Craniosynostosis is a pathologic craniofacial disorder and is defined as the premature fusion of one or more cranial (calvarial) sutures. Cranial sutures are fibrous joints consisting of nonossified mesenchymal cells that play an important role in the development of healthy craniofacial skeletons. Early fusion of these sutures results in incomplete brain development that may lead to complications of several severe medical conditions including seizures, brain damage, mental delay, complex deformities, strabismus, and visual and breathing problems. As a congenital disease, craniosynostosis has a heterogeneous origin that can be affected by genetic and epigenetic alterations, teratogens, and environmental factors and make the syndrome highly complex. To date, approximately 200 syndromes have been linked to craniosynostosis. In addition to being part of a syndrome, craniosynostosis can be nonsyndromic, formed without any additional anomalies. More than 50 nuclear genes that relate to craniosynostosis have been identified. Besides genetic factors, epigenetic factors like microRNAs and mechanical forces also play important roles in suture fusion. As craniosynostosis is a multifactorial disorder, evaluating the craniosynostosis syndrome requires and depends on all the information obtained from clinical findings, genetic analysis, epigenetic or environmental factors, or gene modulators. In this review, we will focus on embryologic and genetic studies, as well as epigenetic and environmental studies. We will discuss published studies and correlate the findings with unknown aspects of craniofacial disorders.

Impact of extra-axial cerebrospinal fluid collection in frontal morphology after surgical treatment of scaphocephaly

Background

Infants with sagittal suture synostosis often present a pathologic dilatation of subarachnoid spaces. The impact of such subarachnoid spaces' enlargement in the morphology of the skull, especially on the forehead and on the surgical outcome, was analyzed.

Methods

Children less than 6 months of age undergoing a surgical correction of the scaphocephaly with Renier's H technique between 2003 and 2008 were included in the study. In these patients, preoperative and postoperative fronto-occipital diameter (FOD), biparietal diameter (BPD), temporal width (TW), and naso-frontal angle (NFA) were measured. Cranial index (CI) and the difference between preoperative and postoperative CI (ΔCI) were calculated. Preoperative cranio-cortical width (CCW) was measured to analyze the subarachnoid spaces' volumes. The children here considered were then divided into two groups: Group 1 with CCW within normal estimated value corrected for age and Group 2 with CCW larger than estimated normal value.

Results

About 159 children were enrolled (72.3% male). CCW was larger than expected in 95 children (59.8%). A positive correlation between CCW and BPD (P ≤ 0.001) and a negative correlation between CCW and NFA (P ≤ 0.001) were found. When comparing the two groups, the mean age at preoperative computed tomography (CT) scan was 121 days in Group 1 and 110 days in Group 2. The mean age at operation was 130 days in Group 1 and 123 in Group 2. The mean age at postoperative examination (RX or CT scan) was 53.4 months in Group 1 and 51.8 months in Group 2. Preoperatively, the mean BPD, TW, and CI were significantly larger in Group 2 (P ≤ 0.01), whereas the NFA was significantly narrower (P = 0.03). Postoperative analysis showed that ΔCI was statistically different between the two groups (Group 1: 10%, Group 2: 7%; P < 0.04). The duration of follow-up period ranged between 19 and 129 months.

Conclusion

Two main subtypes of forehead of infants with scaphocephaly may be distinguished. Indeed, the morphology of the forehead differs when a pathologic subarachnoid spaces' enlargement is present preoperatively and it also affects the postoperative evolution. Such observation highlights the importance of evaluating whether subarachnoid spaces are enlarged when planning a surgical correction in isolated sagittal suture synostosis.

Non-syndromic craniosynostosis in children: Scoping review

Background

Craniosynostosis (CS) is a complex condition consisting of the early fusion of one or more cranial sutures in the intrauterine stage. The affected infant exhibits abnormal head shape at time of birth or shortly thereafter. It can be observed in normal individuals (non-syndromic CS or NSCS) or as a part of a multisystem syndrome. The purposes of the present article were to carry out a scoping review on Non-Syndromic CS and to discuss the most important findings retrieved.

Material and Methods

The steps of this scoping review were as follows: first, to pose a research question; second, to identify relevant studies to answer the research question; third, to select and retrieve the studies; fourth, to chart the critical data, and finally, to collate, summarize, and report the results from the most important articles. Relevant articles published over a 20-year period were identified and retrieved from five Internet databases: PubMed; EMBASE; Cochrane Library; Google Scholar, and EBSCO.

Results

Fourteen articles were finally included in the present scoping review. The following four most important clinical issues are discussed: (i) normal cranial development, clinical manifestations, and pathogenesis of NCSC; (ii) clinical evaluation of NCSC; (iii) treatment and post-surgical follow-up; and (iv) additional considerations.

Conclusions

NSCS may be present with associated head shapes. Multiple early surgical reconstructive options are currently available for the disorder. Pediatric Dentistry practitioners must be familiarized with this condition and form part of a multi-approach health team as those responsible for the opportune oral health care of the affected child.

Key words:Craniosynostosis, cranial development, children, scoping review, dental management.

Recombinant mouse periostin ameliorates coronal sutures fusion in Twist1+/- mice

BACKGROUND

Saethre-Chotzen syndrome is an autosomal dominantly inherited disorder caused by mutations in the twist family basic helix-loop-helix transcription factor 1 (TWIST1) gene. Surgical procedures are frequently required to reduce morphological and functional defects in patients with Saethre-Chotzen syndrome. Therefore, the development of noninvasive procedures to treat Saethre-Chotzen syndrome is critical. We identified that periostin, which is an extracellular matrix protein that plays an important role in both bone and connective tissues, is downregulated in craniosynostosis patients.

METHODS

We aimed to verify the effects of different concentrations (0, 50, 100, and 200 μg/l) of recombinant mouse periostin in Twist1^+/- mice (a mouse model of Saethre-Chotzen syndrome) coronal suture cells in vitro and in vivo. Cell proliferation, migration, and osteogenic differentiation were observed and detected. Twist1^+/- mice were also injected with recombinant mouse periostin to verify the treatment effects.

RESULTS

Cell Counting Kit-8 results showed that recombinant mouse periostin inhibited the proliferation of suture-derived cells in a time- and concentration-dependent manner. Cell migration was also suppressed when treated with recombinant mouse periostin. Real-time quantitative PCR and Western blotting results suggested that messenger ribonucleic acid and protein expression of alkaline phosphatase, bone sialoprotein, collagen type I, and osteocalcin were all downregulated after treatment with recombinant mouse periostin. However, the expression of Wnt-3a, Wnt-1, and β-catenin were upregulated. The in vivo results demonstrated that periostin-treated Twist1^+/- mice showed patent coronal sutures in comparison with non-treated Twist1^+/- mice which have coronal craniosynostosis.

CONCLUSION

Our results suggest that recombinant mouse periostin can inhibit coronal suture cell proliferation and migration and suppress osteogenic differentiation of suture-derived cells via Wnt canonical signaling, as well as ameliorate coronal suture fusion in Twist1^+/- mice.

Spring-Assisted Surgery in the Treatment of Complex Craniosynostosis

Multisutural nonsyndromic craniosynostosis is a rare group of malformations, whose frequency has been reported between 3% and 7% of all craniosynostosis. The clinical diagnosis can be difficult and computed tomography is usually required. Surgical treatment is challenging and staged procedures are performed in up to 80% of patients. The aim of the present study was to determine the reoperation rate and to evaluate the surgical outcomes by measuring intracranial volume (ICV) preoperatively and at follow-up, and comparing it to a control group. Perioperative variables and reoperation rate were recorded. Fifty-one patients presented with a complex pattern of synostosis without a recognizable syndrome (5% of cases of total patients evaluated). Fifteen patients have been treated with spring-assisted surgery, either alone or in combination with a foreheadplasty. The mean follow-up was 6.2 years. The mean preoperative ICV of the patients was smaller, but not significantly, than in the normal population (P = 0.13). Postoperatively, the mean ICV was similar to that of the control group at 1 year (P = 0.92), while at 3 years it was appreciably smaller, although not significantly different (P = 0.06). Five patients (33%) went through a secondary skull expansion for either raised intracranial pressure or cosmetic reasons. Spring-assisted surgery seems to temporarily expand ICV in children with complex synostosis and lower the reoperation rate, thus reducing the need for a second procedure. A longer follow-up would be necessary to further investigate the effects of springs over time.

Robust head CT image registration pipeline for craniosynostosis skull correction surgery

Craniosynostosis is a congenital malformation of the infant skull typically treated via corrective surgery. To accurately quantify the extent of deformation and identify the optimal correction strategy, the patient-specific skull model extracted from a pre-surgical computed tomography (CT) image needs to be registered to an atlas of head CT images representative of normal subjects. Here, the authors present a robust multi-stage, multi-resolution registration pipeline to map a patient-specific CT image to the atlas space of normal CT images. The proposed registration pipeline first performs an initial optimisation at very low resolution to yield a good initial alignment that is subsequently refined at high resolution. They demonstrate the robustness of the proposed method by evaluating its performance on 560 head CT images of 320 normal subjects and 240 craniosynostosis patients and show a success rate of 92.8 and 94.2%, respectively. Their method achieved a mean surface-to-surface distance between the patient and template skull of <2.5 mm in the targeted skull region across both the normal subjects and patients.

Low-Dose CT for Craniosynostosis: Preserving Diagnostic Benefit with Substantial Radiation Dose Reduction

BACKGROUND AND PURPOSE

Given the positive impact of early intervention for craniosynostosis, CT is often performed for evaluation but radiation dosage remains a concern. We evaluated the potential for substantial radiation dose reduction in pediatric patients with suspected craniosynostosis.

MATERIALS AND METHODS

CT projection data from pediatric patients undergoing head CT for suspected craniosynostosis were archived. Simulated lower-dose CT images corresponding to 25%, 10%, and 2% of the applied dose were created using a validated method. Three neuroradiologists independently interpreted images in a blinded, randomized fashion. All sutures were evaluated by using 3D volume-rendered images alone, and subsequently with 2D and 3D images together. Reference standards were defined by reader agreement by using routine dose and 2D and 3D images. Performance figures of merit were calculated based on reader response and confidence.

RESULTS

Of 33 pediatric patients, 21 had craniosynostosis (39 positive sutures and 225 negative sutures). The mean volume CT dose index was 15.5 ± 2.3 mGy (range, 9.69-19.38 mGy) for the routine dose examination. Average figures of merit for multireader analysis ranged from 0.92 (95% CI, 0.90-0.95) at routine pediatric dose to 0.86 (95% CI, 0.79-0.94) at 2% dose using 3D images alone. Similarly, pooled reader figures of merit ranged from 0.91 (95% CI, 0.89-0.95) at routine pediatric dose to 0.85 (95% CI, 0.76-0.95) at 2% dose using 2D and 3D images together. At 25% and 10% dose, 95% CI of the difference in figures of merit from routine dose included 0, suggesting similar or noninferior performance.

CONCLUSIONS

For pediatric head CT for evaluation of craniosynostosis, dose reductions of 75%-90% were possible without compromising observer performance.

Craniosynostosis : Updates in Radiologic Diagnosis

The purpose of this article is to review imaging findings and to discuss the optimal imaging methods for craniosynostosis. The discussion of imaging findings are focused on ultrasonography, plain radiography, magnetic resonance imaging and computed tomography with 3-dimensional reconstruction. We suggest a strategy for imaging work-up for the diagnosis, treatment planning and follow-up to minimize or avoid ionized radiation exposure to children by reviewing the current literature.

Computer-assisted shape descriptors for skull morphology in craniosynostosis

PURPOSE

Our aim was to develop a novel method for characterizing common skull deformities with high sensitivity and specificity, based on two-dimensional (2D) shape descriptors in computed tomography (CT) images.

METHODS

Between 2003 and 2014, 44 normal subjects and 39 infants with craniosynostosis (sagittal, 29; bicoronal, 10) enrolled for analysis. Mean age overall was 16 months (range, 1-120 months), with a male:female ratio of 56:29. Two reference planes, sagittal (S-plane: through top of lateral ventricle) and coronal (C-plane: at maximum dimension of fourth ventricle), were utilized to formulate three 2D shape descriptors (cranial index [CI], cranial radius index [CR], and cranial extreme spot index [CES]), which were then applied to S- and C-plane target images of both groups.

RESULTS

In infants with sagittal craniosynostosis, CI in S-plane (S-CI) usually was <1.0 (mean, 0.78; range, 0.67-0.95), with CR consistently at 3 and a characteristic CES pattern of two discrete hot spots oriented diagonally. In the bicoronal craniosynostosis subset, CI was >1.0 (mean 1.11; range, 1.04-1.25), with CR at -3 and a CES pattern of four discrete diagonally oriented hot spots. Scatter plots underscored the highly intuitive joint performance of CI and CES in distinguishing normal and deformed states. Altogether, these novel 2D shape descriptors enabled effective discrimination of sagittal and bicoronal skull deformities.

CONCLUSIONS

Newly developed 2D shape descriptors for cranial CT imaging enabled recognition of common skull deformities with statistical significance, perhaps providing impetus for automated CT-based diagnosis of craniosynostosis.

Cranial Ultrasound as a First-Line Imaging Examination for Craniosynostosis

BACKGROUND

Radiography, typically the first-line imaging study for diagnosis of craniosynostosis, exposes infants to ionizing radiation. We aimed to compare the accuracy of cranial ultrasound (CUS) with radiography for the diagnosis or exclusion of craniosynostosis.

METHODS

Children aged 0 to 12 months who were assessed for craniosynostosis during 2011-2013 by using 4-view skull radiography and CUS of the sagittal, coronal, lambdoid, and metopic sutures were included in this prospective study. Institutional review board approval and parental informed consent were obtained. CUS and radiography were interpreted independently and blindly by 2 pediatric radiologists; conflicts were resolved in consensus. Sutures were characterized as closed, normal, or indeterminate. Correlation between CUS and radiography and interreader agreement were examined for each suture.

RESULTS

A total of 126 children (82 boys, 64.5%) ages 8 to 343 days were included. All sutures were normal on CUS and radiography in 115 patients (93.7%); craniosynostosis of 1 suture was detected in 8 (6.3%, 5 sagittal, 2 metopic, 1 coronal). In 3 cases the metopic suture was closed (n = 2) or indeterminate on CUS (n = 1) but normally closed on radiography. CUS sensitivity was 100%, specificity 98% (95% confidence interval 94%-100%). Reader agreement was 100% for sagittal, coronal, and lambdoid sutures (κ = 0.80); after consensus, disagreement remained on 3 metopic sutures.

CONCLUSIONS

In this series, CUS could be safely used as a first-line imaging tool in the investigation of craniosynostosis, reducing the need for radiographs in young children. Additional assessment may be required for accurate assessment of the metopic suture.

Maternal occupational exposure to polycyclic aromatic hydrocarbons and craniosynostosis among offspring in the National Birth Defects Prevention Study

BACKGROUND

Evidence in animal models and humans suggests that exposure to polycyclic aromatic hydrocarbons (PAHs) may lead to birth defects. To our knowledge, this relationship has not been evaluated for craniosynostosis, a birth defect characterized by the premature closure of sutures in the skull. We conducted a case-control study to examine associations between maternal occupational exposure to PAHs and craniosynostosis.

METHODS

We used data from craniosynostosis cases and control infants in the National Birth Defects Prevention Study (NBDPS) with estimated delivery dates from 1997 to 2002. Industrial hygienists reviewed occupational data from the computer-assisted telephone interview and assigned a yes/no rating of probable occupational PAH exposure for each job from 1 month before conception through delivery. We used logistic regression to assess the association between occupational exposure to PAHs and craniosynostosis.

RESULTS

The prevalence of exposure was 5.3% in case mothers (16/300) and 3.7% in control mothers (107/2,886). We observed a positive association between exposure to PAHs during the 1 month before conception through the third month of pregnancy and craniosynostosis (odds ratio [OR] = 1.75; 95% confidence interval [CI], 1.01-3.05) after adjusting for maternal age and maternal education. The number of cases for each craniosynostosis subtype limited subtype analyses to sagittal craniosynostosis; the odds ratio remained similar (OR = 1.76, 95% CI, 0.82-3.75), but was not significant.

CONCLUSION

Our findings support a moderate association between maternal occupational exposure to PAHs and craniosynostosis. Additional work is needed to better characterize susceptibility and the role PAHs may play on specific craniosynostosis subtypes.

Role of 99mTc-ECD SPECT in the management of children with craniosynostosis

PURPOSE OF THE REPORT

There is a paucity of data on correlation of various imaging modalities with clinical findings in craniosynostosis. Moreover, no study has specifically reported the role of (99m)Tc-ECD SPECT in a large number of subjects with craniosynostosis.

MATERIALS AND METHODS

We prospectively analyzed a cohort of 85 patients with craniosynostosis from year 2007 to 2012. All patients underwent evaluation with (99m)Tc-ECD SPECT and the results were correlated with radiological and surgical findings.

RESULTS

(99m)Tc-ECD SPECT revealed regional perfusion abnormalities in the cerebral hemisphere corresponding to the fused sutures preoperatively that disappeared postoperatively in all the cases. Corresponding to this, the mean mental performance quotient (MPQ) increased significantly (P < 0.05) postoperatively only in those children with absent perfusion defect postoperatively.

CONCLUSIONS

Our study suggests that early surgery and release of craniosynostosis in patients with preoperative perfusion defects (absent on (99m)Tc-ECD SPECT study) are beneficial, as they lead to improved MPQ after surgery.

Identification of skull base sutures and craniofacial anomalies in children with craniosynostosis: utility of multidetector CT

PURPOSE

Craniosynostosis is a condition characterised by the premature fusion of one or more of the cranial sutures. The aim of the study was to identify, by multidetector computed tomography (CT), the involvement of vault sutures as well as of the skull base sutures (named "minor" sutures). The latter ones are involved in development of craniofacial and skull base deformities.

MATERIALS AND METHODS

We retrospectively reviewed 27 children with complex synostosis (n = 21) and anterior synostotic plagiocephaly (n = 6). High-resolution CT images with bone definition algorithm and tridimensional volume rendering reconstructions were assessed.

RESULTS

In 27 children we found different sutures involved in the synostotic process, including both major and minor skull suture synostosis, and synostosis of synchondroses. Superior orbital rim deformity, nasal root deviation, anterior endocranial axis deviation (ethmoidal axis) are found in children with coronal arch synostosis, while reduced size of the posterior fossa and Chiari 1 malformation are noted in children with lambdoid arch synostosis.

CONCLUSIONS

High-resolution CT allows an accurate identification of both "major" and "minor" skull base suture synostosis and it represents the gold standard for the diagnosis of craniostenosis and for planning the proper surgical approach.