The effects of craniosynostosis on the brain with respect to intracranial pressure

Analysis of intracranial pressure waveform using a non-invasive method in individuals with craniosynostosis

PURPOSE

Craniosynostosis can lead to symptoms resulting from cranial compliance (CC) changes and intracranial hypertension (ICH), which may cause cognitive and visual impairment. Non-invasive methods have emerged, including a new device that captures and processes the intracranial pressure waveform (ICPw) by the skull's oscillation. The present study evaluates ICPw obtained non-invasively (NIICPw) in patients with craniosynostosis.

METHODS

This prospective, cross-sectional, and descriptive study was conducted at a single center. Patients diagnosed with craniosynostosis and who provided informed consent were included. A US Food and Drug Administration-approved mechanical extensometer device (Brain4Care Corp.) was used to obtain a NIICPw. An ophthalmologist did a point-of-care retinography to check the optic nerve papilla. The P2/P1 ratio and the morphology of the NIICPw were analyzed, as well as the retinography.

RESULTS

Thirty-five patients were evaluated, and 42 registers were obtained because seven were assessed before and after the surgery. The two patients who presented papilledema had low CC (NIICPw shape Class 3 or 4). There was a significant association between NIICPw and papilledema.

CONCLUSION

The ratio P2/P1 and the NIICPw morphology provided by a non-invasive monitor are related to CC changes before papilledema occurs. This is especially useful in patients with craniosynostosis because invasive ICP monitoring is not always feasible. Further studies are warranted to establish the clinical utility of NIICPw in patients with craniosynostosis.

Cranial Morphology Associated With Syndromic Craniosynostosis: A Potential Detection of Abnormality in Patient's Cranial Growth Using Angular Statistics

INTRODUCTION

Apert, Crouzon, and Pfeiffer syndromes are common genetic syndromes related to syndromic craniosynostosis (SC), whereby it is a congenital defect that occurs when the cranial growth is distorted. Identifying cranial angles associated with these 3 syndromes may assist the surgical team to focus on a specific cranial part during the intervention planning, thus optimizing surgical outcomes and reducing potential morbidity.

OBJECTIVE

The aim of this study is to identify the cranial angles, which are associated with Apert, Crouzon, and Pfeiffer syndromes.

METHODS

The cranial computed tomography scan images of 17 patients with SC and 22 control groups aged 0 to 12 years who were treated in the University Malaya Medical Centre were obtained, while 12 angular measurements were attained using the Mimics software. The angular data were then divided into 2 groups (patients aged 0 to 24 months and >24 months). This work proposes a 95% confidence interval (CI) for angular mean to detect the abnormality in patient's cranial growth for the SC syndromes.

RESULTS

The 95% CI of angular mean for the control group was calculated and used as an indicator to confirm the abnormality in patient's cranial growth that is associated with the 3 syndromes. The results showed that there are different cranial angles associated with these 3 syndromes.

CONCLUSIONS

All cranial angles of the patients with these syndromes lie outside the 95% CI of angular mean of control group, indicating the reliability of the proposed CI in the identification of abnormality in the patient's cranial growth.

Understanding the development, pathogenesis, and injury response of meningeal lymphatic networks through the use of animal models

Meningeal lymphatic vessels (MLVs) help maintain central nervous system (CNS) homeostasis via their ability to facilitate macromolecule waste clearance and neuroimmune trafficking. Although these vessels were overlooked for centuries, they have now been characterized in humans, non-human primates, and rodents. Recent studies in mice have explored the stereotyped growth and expansion of MLVs in dura mater, the various transcriptional, signaling, and environmental factors regulating their development and long-term maintenance, and the pathological changes these vessels undergo in injury, disease, or with aging. Key insights gained from these studies have also been leveraged to develop therapeutic approaches that help augment or restore MLV functions to improve brain health and cognition. Here, we review fundamental processes that control the development of peripheral lymphatic networks and how these might apply to the growth and expansion of MLVs in their unique meningeal environment. We also emphasize key findings in injury and disease models that may reveal additional insights into the plasticity of these vessels throughout the lifespan. Finally, we highlight unanswered questions and future areas of study that can further reveal the exciting therapeutic potential of meningeal lymphatics.

The Paediatric Vault Score (PVS)-A Novel Scoring Tool for Prioritisation of Surgical Management of Craniosynostosis Patients

Craniosynostosis is the premature fusion of the skull sutures, resulting in abnormal skull shape and volume. Timely management is a priority in avoiding raised intracranial pressure which can result in blindness and neurodevelopmental delay. Due to the COVID-19 pandemic, theater access was reduced. A risk stratification scoring system was thus devised to score patients attending surgery and aid in prioritization according to surgical need. The authors present the Paediatric Vault Score (PVS), which can also be customized to each unit's individual protocols. Ten patients on the waiting list were randomly selected and their clinical information was summarized in uniform anonymized reports. Six craniofacial consultants were selected as assessors and given 1 week to independently rank the patients from 1 to 10. Each scorer's ranking was verified against the PVS template and concordance was analyzed using the Kendall tau correlation coefficient (KT). Three cycles of the scoring process were carried out. Improvements were made to the scoring tool following cycle 1. Cycle 1 revealed 2 clinicians to be concordant with the PVS system and 4 to be discordant. Cycle 2 revealed all 6 clinicians to be concordant, with a mean KT score of 0.61. The final cycle revealed all 6 clinicians to be concordant, with a mean KT score of 0.70. Four scorers increased their concordance once the scoring sheet was introduced. Kendall's correlation of concordance calculated the interrater reliability to be 0.81. The PVS is the first known vault scoring system to aid in risk stratification and waiting list prioritization.

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.

Scaphocephaly and increased intra-cranial pressure in non-operated adults: A controlled anthropological study on 21 skulls

AIM AND SCOPE

The prevalence of increased intra-cranial pressure (ICP) in patients with scaphocephaly is controversial. Here, based on anthropological material, we aimed to determine whether adults with non-operated sagittal synostosis show indirect signs of increased ICP.

MATERIALS AND METHODS

Thirty-eight dry skulls (21 skulls with sagittal craniosynostosis and 17 controls) were selected from the collections of the National Museum of Natural History (Paris, France). All skulls registered as 'fused sagittal suture' or 'scaphocephaly' in the registry of the Museum were included. All had total fusion of the sagittal suture. Controls were selected within skulls of similar origin (France), without visible craniofacial anomalies. The 38 skulls were CT-scanned using a standard medical CT-scan with a protocol dedicated to dry bone imaging. Eight radiological signs associated with raised ICP were assessed: (1) calvaria and (2) skull base thinning, (3) dorsum sellae erosion, (4) sella turcica lengthening, (5) copper beaten skull, (6) suture diastasis, (7) persistent metopic suture, and (8) small frontal sinus. Scaphocephaly was assessed based on head circumference, cranial index, intra-cranial volume, fronto-nasal angle, and inter-zygomatic distance. Linear and non-linear logistic models were used to compare groups.

RESULTS

19/21 skulls with sagittal synostosis were significantly scaphocephalic. None of the criteria for ICP were significantly different in skulls with scaphocephaly relative to controls. Nevertheless, 5 individual skulls with scaphocephaly had ≥ 3 signs in favor of a history of raised ICP. We do not report the significant prevalence of indirect signs of raised ICP in adults with scaphocephaly. These results do not allow ruling out a history of early raised ICP or of minor prolonged raised ICP. Even though our findings support the fact that scaphocephaly is not significantly associated with prolonged raised ICP, individual cases (5/21) with clear signs in favor of a history of brain compression indicate that scaphocephaly correction should be considered as a functional procedure until the production of clear evidence. Cognitive assessments of non-operated adult patients with scaphocephaly could contribute to tackle this recurring question in craniofacial surgery.

The use of a single-piece bone flap for cranial reshaping in anterior craniosynostosis patients: clinical experience and a description of a novel technique

Background

Craniosynostosis is known as premature closure of one or more of the cranial sutures. Anterior craniosynostosis involves anterior plagiocephaly and trigonocephaly. One of the issues in anterior craniosynostosis skull reshaping is maintaining an aesthetically pleasing forehead curve. Therefore, in this article, we demonstrate our novel technique to use a single-piece bone flap for cranial reshaping of the anterior mold in patients diagnosed with anterior craniosynostosis. A retrospective record review of patients who underwent single piece bone flap cranial reshaping for correction of unicoronal synostosis (UCS) and metopic synostosis (MS) at an Academic Institute in Riyadh, Saudi Arabia, between 2018 and 2020, was conducted.

Results

Six non-syndromic consecutive patients were included. Three of the patients had MS. The mean age at surgery was 11.16 months (range, 6–19 months). The average OR time was 315 min (range, 263–368 min). The average intraoperative blood loss was 225 ml (range, 100–400 ml). All patients had achieved acceptable functional and aesthetic results.

Conclusion

Our novel technique is an innovative and efficient reconstructive technique to simultaneously address MS and UCS and minimize intraoperative bleeding and surgery time. However, more studies with more cases are required.

[Cranial suture ultrasound for reducing radiation exposure in diagnosis of craniosynostosis in young children]

Currently, there are no standards for examining patients with suspected craniosynostosis. CT of the brain with 3D skull reconstruction is a common approach to diagnose craniosynostosis in many hospitals. This technique in pediatric patients is associated with a high dose of ionizing radiation and prompts searching for other diagnostic methods.

OBJECTIVE

To generalize an experience of cranial suture ultrasound and compare diagnostic capabilities of various ultrasound devices.

MATERIAL AND METHODS

We retrospectively analyzed data of cranial suture ultrasound in 49 patients under the age of 14 months with a suspected craniosynostosis. All patients underwent expert-class ultrasound. Of these, 10 patients underwent middle-class ultrasound. Age of these patients ranged from 2 to 10 months.

RESULTS

According to ultrasound data, we have found 48 synostotic sutures in 42 patients. There were 2 inaccurate results among these 48 sutures. In both cases, expert-class ultrasound confirmed partial closure of cranial sutures while 3D CT revealed their complete closure. Sensitivity and specificity of technique were 95.8% and 100%, respectively. Both expert- and middle-class ultrasound revealed synostotic sutures in 10 children under 1 year old.

CONCLUSION

Our data have shown that ultrasound of cranial sutures may be a first-line imaging technique. This method has high sensitivity and specificity in pediatric patients. Moreover, middle-class ultrasound devices may be used for diagnosis.

Quality of life and satisfaction in surgical versus conservative treatment of nonsyndromic children with craniosynostosis

OBJECTIVE

Craniosynostosis represents the second most common reason for referral to pediatric neurosurgery. However, the quality of life and neurodevelopmental impact of leaving this physical disorder uncorrected is poorly understood.

METHODS

This multicenter cross-sectional study identified previously managed nonsyndromic infants (< 24 months of age) with single-suture craniosynostosis at both pediatric neurosurgical centers in Alberta, Canada. The primary variable of interest was the allocated treatment (surgical vs conservative). The primary outcome was the Pediatric Quality of Life Inventory (PedsQL), a validated measure of quality of life examining physical, emotional, social, and school functioning. Treatment decision satisfaction and the reasons for selected management were quantified and collected directly from caregivers.

RESULTS

One hundred fourteen children met the inclusion criteria: 78% underwent surgery and 22% had conservative treatment. The most common suture affected was sagittal (54%), followed by metopic (33%), coronal (10%), and lambdoid (3%). Caregivers most commonly opted for surgery because of severe appearance (80%). Seventy-six percent and 72% of the caregivers of children with conservative management did so due to concerns of surgical risks and mild appearance, respectively. There was a statistically significant relationship between both the parents' (p < 0.001) and the surgeon's (p = 0.001) impression of a severe head shape and surgical management. Parental satisfaction with their child's appearance as well as satisfaction with their treatment decision did not differ between management types. Regarding quality of life, on univariate analysis, the conservative group had a statistically higher physical summary score (p = 0.01), psychosocial summary score (p = 0.004), and mean total scale score (p = 0.003) compared to the surgical group. However, after adjusting for severity and age at consult, no significant independent associations between management type and any of the PedsQL summary scores were found.

CONCLUSIONS

Alberta families have a high number of children with craniosynostosis treated with conservative management. Conservatively managed infants were largely minimally affected patients, particularly those with metopic synostosis. The study found no independent association between management type (surgery vs conservative) and quality of life when adjusted for important patient factors.

Open Repair Versus Closed Repair: A Cost-Analysis of the Two Surgical Approaches for the Treatment of Craniosynostoses

PURPOSE

The purpose of this study was to quantify the hospitalization charges of the 2 general surgical approaches in the treatment of craniosynostosis and determine if there was a significant difference between the 2. Several studies compared them side-by-side according to specific variables, such as success rates, postoperative complications, blood loss, and length of stay, but were limited by small sample sizes.

METHODS

This is a retrospective cohort study that was conducted using the Kids' Inpatient Database (KID). All patients diagnosed with craniosynostosis (Q75.0) were identified. The procedures were grouped according to the approach taken, whether it was a traditional, open approach, or a closed, minimally invasive approach. The primary predictor variable was the surgical approach (open vs closed). The outcome variables were the hospital charges (US dollars) and length of stay (days). Statistical analyses were based on the univariate and multivariate linear regression models, and P value less than .05 marked the significance level.

RESULTS

Among a sample of 2,585 cases, an open approach was employed in 2,353 cases and a closed approach in 232 cases. Race, payer information, hospital region, admission status (elective vs not elective), patient location, and surgical approach (open vs closed) were all significant predictors (P < .15) of increased hospitalization charges. Relative to white patients, being in the 'other' racial class added $10,987 in hospital charges (P < .05). Relative to the Northeast, being a patient in the West added $33,459 in hospital charges (P < .01). Not being admitted electively added $72,572 (P < .01) relative to elective admissions. Finally, open repair added $59,539 (P < .01) in charges relative to closed repair.

CONCLUSIONS

The traditional open approach added nearly $60,000 to the cost of the procedure when compared with the closed, endoscopic approach. The scope and invasiveness of the open approach demand greater surgical services, hospital services, supplies, and equipment, ultimately contributing to this increased cost.

Combining deep learning with 3D stereophotogrammetry for craniosynostosis diagnosis

Craniosynostosis is a condition in which cranial sutures fuse prematurely, causing problems in normal brain and skull growth in infants. To limit the extent of cosmetic and functional problems, swift diagnosis is needed. The goal of this study is to investigate if a deep learning algorithm is capable of correctly classifying the head shape of infants as either healthy controls, or as one of the following three craniosynostosis subtypes; scaphocephaly, trigonocephaly or anterior plagiocephaly. In order to acquire cranial shape data, 3D stereophotographs were made during routine pre-operative appointments of scaphocephaly (n = 76), trigonocephaly (n = 40) and anterior plagiocephaly (n = 27) patients. 3D Stereophotographs of healthy infants (n = 53) were made between the age of 3-6 months. The cranial shape data was sampled and a deep learning network was used to classify the cranial shape data as either: healthy control, scaphocephaly patient, trigonocephaly patient or anterior plagiocephaly patient. For the training and testing of the deep learning network, a stratified tenfold cross validation was used. During testing 195 out of 196 3D stereophotographs (99.5%) were correctly classified. This study shows that trained deep learning algorithms, based on 3D stereophotographs, can discriminate between craniosynostosis subtypes and healthy controls with high accuracy.

A Novel Sand Dollar and Staves Technique for Unilateral Lambdoid Craniosynostosis

BACKGROUND

Unilateral lambdoid synostosis (ULS) is the rarest form of craniosynostosis. Due to the associated cranio-caudal shift seen in ULS, surgical correction is technically challenging from a morphological standpoint. Herein, the authors present a novel "Sand-Dollar and Staves" technique for the repair of ULS.

METHODS

A zigzag coronal incision is performed, and an anteriorly-based pericranial flaps are elevated. Prefabricated cutting guides are placed and the calvarium is marked. To treat the flattening on the ipsilateral side, a wedged suturectomy is performed with additional barrel staves. A large circle centered over the bulging on the contralateral side is cut out above the open lambdoid suture. This piece is barrel staved in a radial fashion, leaving the center intact and creating a Sand-Dollar appearance. This disk is then flattened and trimmed. The modified Sand-Dollar is fixed using an absorbable plating system. While gentle pressure is applied to the Sand-Dollar piece as it is being secured, the ipsilateral side demonstrates compensatory filling. Results are evaluated using the Whitaker Classification.

RESULTS

Four patients underwent surgical correction with this technique. The procedure was performed at mean age of 11.7 months. The mean operative time was 2.5 hours. Intraoperative blood loss was 50 to 100 ml. Total hospitalization time was 2 to 3 days. No post-operative complications were encountered. Whitaker scores ranged from 1 to 1.5. The mean follow-up was 10 months.

CONCLUSION

The Sand-Dollar and Staves procedure is a novel, single-stage approach for the management of ULS with decreased operative time, blood loss, and hospital stay with satisfactory aesthetic outcomes.

Intracranial pressure, brain morphology and cognitive outcome in children with sagittal craniosynostosis

BACKGROUND

Patients with sagittal craniosynostosis are at increased risk of developing raised intracranial pressure (ICP) and neurocognitive deficiencies such as reduced attention, planning, speech, behavioural and learning disabilities.

AIM

To determine if the existing literature supports a correlation between elevated ICP and negative cognitive outcome in patients with sagittal craniosynostosis. Secondly, to investigate if the risk of developing neurocognitive deficiencies can be explained by changes in brain morphology in this patient category.

METHODS

Systematic literature review in PubMed.

RESULTS

A total of 190 publications were reviewed to determine a possible correlation between raised ICP and cognitive outcome, of which four were included in the study. No significant association was found. Forty-four publications on brain morphology in sagittal craniosynostosis were identified, of which 11 were included in the review. Clear evidence of morphologic changes in multiple areas of the brains of sagittal craniosynostosis patients was found in the literature.

CONCLUSION

The existing literature does not support an association between increased ICP and negative global cognitive outcome measures in patients with sagittal craniosynostosis. Brain morphology is altered in areas related to neurocognition and language in the same patient group. These changes might play a role in the development of neurocognitive deficiencies, though no definitive link is yet established, and further investigation is warranted.

[Endoscopic treatment of nonsyndromic sagittal craniosynostosis in dizygotic twins. A case report and literature review]

The article presents a rare clinical case of isolated sagittal craniosynostosis in dichorionic diamniotic twins. The review addresses issues of epidemiology, etiology, and pathogenesis of craniosynostosis in this group of patients.

Health-related quality of life in children after surgical treatment of non-syndromal craniosynostosis

PURPOSE

Craniosynostosis is a premature ossification of the fibrous sutures in a skull which results in a changing of the growth pattern of the skull with abnormal head shapes, midface hypoplasia, and neurofunctional disorders. Surgical correction of craniosynostosis by opening the ossified cranial sutures is usually made in the infant phase to avoid compression of the brain and mental deficits. However, little is known regarding the health-related quality of life among children after surgical treatment of diverse forms of craniosynostosis. The purpose of this study was to evaluate the quality of life of adolescent patients who anderwent a surgical correction of non-syndromal craniosynostosis in infancy.

MATERIALS AND METHODS

The study population included 48 adolescents with an average age of 12.1 ± 4.3 years. The KINDL questionnaire, which was specifically validated for children, was used to estimate different dimensions of quality of life and the impact of various factors on it.

RESULTS

In the investigated group, boys were more likely to be affected by non-syndromal craniosynostosis than were girls. Children and their parents showed a high degree of correlation in each of the investigated dimensions of the KINDL questionnaire. Sex, the type of craniosynostosis, surgical technique, and surgical result did not seem to have an influence on the quality of life. A negative correlation between the time of surgery and the family-related quality of life could be shown. None of the patients in the study had relevant limitations or impairments in their later life.

CONCLUSIONS

In our study, patients with simple non-syndromic craniosynostoses who anderwent operative correction of craniosynostosis in infancy do not show any quality-of-life limitations in their later life compared to the average population.

Hedgehog Signaling and Embryonic Craniofacial Disorders

Since its initial discovery in a Drosophila mutagenesis screen, the Hedgehog pathway has been revealed to be instrumental in the proper development of the vertebrate face. Vertebrates possess three hedgehog paralogs: Sonic hedgehog (Shh), Indian hedgehog (Ihh), and Desert hedgehog (Dhh). Of the three, Shh has the broadest range of functions both in the face and elsewhere in the embryo, while Ihh and Dhh play more limited roles. The Hedgehog pathway is instrumental from the period of prechordal plate formation early in the embryo, until the fusion of the lip and secondary palate, which complete the major patterning events of the face. Disruption of Hedgehog signaling results in an array of developmental disorders in the face, ranging from minor alterations in the distance between the eyes to more serious conditions such as severe clefting of the lip and palate. Despite its critical role, Hedgehog signaling seems to be disrupted through a number of mechanisms that may either be direct, as in mutation of a downstream target of the Hedgehog ligand, or indirect, such as mutation in a ciliary protein that is otherwise seemingly unrelated to the Hedgehog pathway. A number of teratogens such as alcohol, statins and steroidal alkaloids also disrupt key aspects of Hedgehog signal transduction, leading to developmental defects that are similar, if not identical, to those of Hedgehog pathway mutations. The aim of this review is to highlight the variety of roles that Hedgehog signaling plays in developmental disorders of the vertebrate face.

Changes in delta ADC reflect intracranial pressure changes in craniosynostosis

BACKGROUND

In patients with craniosynostosis, intracranial pressure (ICP) has been reported to increase even in the absence of overt symptoms. The early and non-invasive detection of intracranial hypertension is important for reducing the risk of abnormal brain development in pediatric patients.

PURPOSE

To assess whether the apparent diffusion coefficient (ADC) of white matter during the cardiac cycle (ΔADC) would change after surgery to relieve ICP in children with craniosynostosis.

MATERIAL AND METHODS

This prospective study included ten patients diagnosed with craniosynostosis and four normal controls. All ten patients underwent magnetic resonance (MR) examinations before and after surgical treatment. Single-shot diffusion MR imaging (MRI) triggered by an electrocardiogram was performed, with regions of interest (ROIs) placed on frontal white matter and basal ganglia.

RESULTS

In all ten patients, ΔADC values after surgery were higher than those before surgery. This difference was statistically significant (Wilcoxon signed-rank test, P = 0.005).

CONCLUSION

The change in ΔADC in the frontal white matter before and after surgery in patients with craniosynostosis indicates that it might reflect the change in ICP. Measurements of ΔADC could be a promising tool for non-invasive monitoring of ICP.

Integration of Brain and Skull in Prenatal Mouse Models of Apert and Crouzon Syndromes

The brain and skull represent a complex arrangement of integrated anatomical structures composed of various cell and tissue types that maintain structural and functional association throughout development. Morphological integration, a concept developed in vertebrate morphology and evolutionary biology, describes the coordinated variation of functionally and developmentally related traits of organisms. Syndromic craniosynostosis is characterized by distinctive changes in skull morphology and perceptible, though less well studied, changes in brain structure and morphology. Using mouse models for craniosynostosis conditions, our group has precisely defined how unique craniosynostosis causing mutations in fibroblast growth factor receptors affect brain and skull morphology and dysgenesis involving coordinated tissue-specific effects of these mutations. Here we examine integration of brain and skull in two mouse models for craniosynostosis: one carrying the FGFR2c C342Y mutation associated with Pfeiffer and Crouzon syndromes and a mouse model carrying the FGFR2 S252W mutation, one of two mutations responsible for two-thirds of Apert syndrome cases. Using linear distances estimated from three-dimensional coordinates of landmarks acquired from dual modality imaging of skull (high resolution micro-computed tomography and magnetic resonance microscopy) of mice at embryonic day 17.5, we confirm variation in brain and skull morphology in Fgfr2c^C342Y/+ mice, Fgfr2^+/S252W mice, and their unaffected littermates. Mutation-specific variation in neural and cranial tissue notwithstanding, patterns of integration of brain and skull differed only subtly between mice carrying either the FGFR2c C342Y or the FGFR2 S252W mutation and their unaffected littermates. However, statistically significant and substantial differences in morphological integration of brain and skull were revealed between the two mutant mouse models, each maintained on a different strain. Relative to the effects of disease-associated mutations, our results reveal a stronger influence of the background genome on patterns of brain-skull integration and suggest robust genetic, developmental, and evolutionary relationships between neural and skeletal tissues of the head.

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.

Deformed Skull Morphology Is Caused by the Combined Effects of the Maldevelopment of Calvarias, Cranial Base and Brain in FGFR2-P253R Mice Mimicking Human Apert Syndrome

Apert syndrome (AS) is a common genetic syndrome in humans characterized with craniosynostosis. Apert patients and mouse models showed abnormalities in sutures, cranial base and brain, that may all be involved in the pathogenesis of skull malformation of Apert syndrome. To distinguish the differential roles of these components of head in the pathogenesis of the abnormal skull morphology of AS, we generated mouse strains specifically expressing mutant FGFR2 in chondrocytes, osteoblasts, and progenitor cells of central nervous system (CNS) by crossing Fgfr2^+/P253R-Neo mice with Col2a1-Cre, Osteocalcin-Cre (OC-Cre), and Nestin-Cre mice, respectively. We then quantitatively analyzed the skull and brain morphology of these mutant mice by micro-CT and micro-MRI using Euclidean distance matrix analysis (EDMA). Skulls of Col2a1-Fgfr2^+/P253R mice showed Apert syndrome-like dysmorphology, such as shortened skull dimensions along the rostrocaudal axis, shortened nasal bone, and evidently advanced ossification of cranial base synchondroses. The OC-Fgfr2^+/P253R mice showed malformation in face at 8-week stage. Nestin-Fgfr2^+/P253R mice exhibited increased dorsoventral height and rostrocaudal length on the caudal skull and brain at 8 weeks. Our study indicates that the abnormal skull morphology of AS is caused by the combined effects of the maldevelopment in calvarias, cranial base, and brain tissue. These findings further deepen our knowledge about the pathogenesis of the abnormal skull morphology of AS, and provide new clues for the further analyses of skull phenotypes and clinical management of AS.

Expansion of the variable expression of Muenke syndrome: Hydrocephalus without craniosynostosis

Muenke syndrome (MS) is an autosomal dominant coronal craniosynostosis syndrome with variable extracranial anomalies. We studied 56 unrelated patients with non-syndromic uni- or bicoronal craniosynostosi to identify the frequency and clinical characteristics of MS in a cohort of Mexican childrens. The FGFR3 pathogenic variation p.Pro250Arg responsible for MS was characterized in all probands by PCR-restriction assay; available first-degree relatives (15 parents, 5 siblings) of the confirmed p.Pro250Arg carriers were also tested. All heterozygotes for p.Pro250Arg underwent clinical and audiologic assessment, as well as X-ray evaluations of hands and feet. Eight of 56 probands (14%) were found to carry the p.Pro250Arg variant and half of them were familial cases. Four p.Pro250Arg heterozygous familial members had been considered unaffected before the molecular testing. In one MS family, hydrocephalus without craniosynostosis, was documented as the only clinical manifestation in a previously undetected heterozygous male sibling. Hydrocephalus without craniosynostosis in a patient with the p.Pro250Arg variant suggests that some patients with MS might present only this manifestation; to our knowledge, hydrocephalus has not been described as isolated feature in MS, so we propose to consider this feature as an expansion of the MS phenotype rather than an unrelated finding. Our data also reinforce the notion that molecular testing of FGFR3 must be included in the diagnostic approach of coronal craniosynostosis. This will allow accurate genetic counseling and optimal management of MS, which might otherwise go undiagnosed because of mild manifestations and wide variability of expression. © 2016 Wiley Periodicals, Inc.

Lumbar Puncture Pressures During Childhood in 262 Children with Craniosynostosis

OBJECTIVE

The aim of this study was to analyze age-dependent lumbar puncture pressures (LPPs) measured in 262 children with craniosynostosis to provide information that assists in determining surgery.

METHODS

From 1 July 2005 to 30 June 2014, 262 children with craniosynostosis diagnosed at the Department of Neurosurgery, Ajou University Hospital, underwent LPP measurement. These children were compared with respect to age, gender, birth weight, head circumference at the time of birth, gestational age, LPP, and developmental assessments.

RESULTS

Changes in LPP in children with craniosynostosis according to age were y = -0.0007x(2) + 0.1327x + 21.678 in all patients overall, y = -0.0003x(2) + 0.1166x + 21.466 in children with single-suture craniosynostosis, and y = -0.002x(2) + 0.248x + 22.55 in patients with multiple and syndromic craniosynostosis, indicating a steady and slow increase from birth until the age of 4 years. Also, 59.9% of the 262 children had LPP greater than 20 cm H2O, but when the LPP cutoff level was adjusted for age, this proportion was 99.2%; the new criterion after the adjusted LPP cutoff level showed that for those with increased LPP, the proportion was 63.4%.

CONCLUSIONS

We suggest that LPP increases slowly with age in children with craniosynostosis, increased LPP rates in children with craniosynostosis were higher than previously expected, and the new cutoff level criterion that adjusts for age may be more helpful than a fixed cutoff level for all ages.

Craniosynostosis in Growing Children : Pathophysiological Changes and Neurosurgical Problems

Craniosynostosis is defined as the premature fusion of one or more cranial sutures resulting in skull deformity. Characteristically, this disorder can cause diverse neurosurgical problems, as well as abnormal skull shape. Intracranial hypertension, hydrocephalus, Chiari malformation and neuropsychological dysfunction are the major neurosurgical concerns in children with craniosynostosis. In this review article, we investigate pathophysiology, characteristics and proper neurosurgical management of these neurosurgical issues, respectively.

Neurodevelopmental Problems in Non-Syndromic Craniosynostosis

Craniosynostosis is the premature fusion of calvarial sutures, resulting in deformed craniofacial appearance. Hence, for a long time, it has been considered an aesthetic disorder. Fused sutures restrict growth adjacent to the suture, but compensatory skull growth occurs to accommodate the growing brain. The primary goal for the management of this craniofacial deformity has been to release the constricted skull and reform the distorted shape of the skull vault. However, the intellectual and behavioral prognosis of affected children has also been taken into consideration since the beginning of the modern era of surgical management of craniosynostosis. A growing body of literature indicates that extensive surgery, such as the whole-vault cranioplasty approach, would result in better outcomes. In addition, the age at treatment is becoming a major concern for optimal outcome in terms of cosmetic results as well as neurodevelopment. This review will discuss major concerns regarding neurodevelopmental issues and related factors.

The Genetic Basis of Hydrocephalus

Studies of syndromic hydrocephalus have led to the identification of >100 causative genes. Even though this work has illuminated numerous pathways associated with hydrocephalus, it has also highlighted the fact that the genetics underlying this phenotype are more complex than anticipated originally. Mendelian forms of hydrocephalus account for a small fraction of the genetic burden, with clear evidence of background-dependent effects of alleles on penetrance and expressivity of driver mutations in key developmental and homeostatic pathways. Here, we synthesize the currently implicated genes and inheritance paradigms underlying hydrocephalus, grouping causal loci into functional modules that affect discrete, albeit partially overlapping, cellular processes. These in turn have the potential to both inform pathomechanism and assist in the rational molecular classification of a clinically heterogeneous phenotype. Finally, we discuss conceptual methods that can lead to enhanced gene identification and dissection of disease basis, knowledge that will potentially form a foundation for the design of future therapeutics.

Central nervous system and cervical spine abnormalities in Apert syndrome

PURPOSE

Apert syndrome characterized by acrocephalosyndactyly is a rare autosomal dominant congenital malformation with a prevalence of 1/65,000 births. With an extensive range of phenotypic and developmental manifestations, its management requires a multidisciplinary approach. A variety of craniofacial, central nervous system (CNS), and cervical spine abnormalities have been reported in these patients. This study aimed to determine the incidence of these CNS abnormalities in our case series.

METHODS

Retrospective review of Australian Craniofacial Unit (ACFU) database for Apert patients was performed. Data collected that included demographics, place of origin, age at presentation, imaging performed, and images were reviewed and recorded. Where available, developmental data was also recorded.

RESULTS

Ninety-four patients seen and managed at the ACFU had their CNS and cervical spine abnormalities documented. The main CNS abnormalities were prominent convolutional markings (67 %), ventriculomegaly (48 %), crowded foramen magnum (36 %), deficient septum pellucidum (13 %), and corpus callosum agenesis in 11 %. Major C-spine findings were present in 50.8 % of patients and included fusion of posterior elements of C5/C6 (50 %) and C3/4 (27 %). Multilevel fusion was seen in 20 %. Other abnormalities were C1 spina bifida occulta (7 %) and atlanto-axial subluxation (7 %).

CONCLUSION

Multiple CNS and cervical spine (c-spine) abnormalities are common in Apert syndrome. The significance of these abnormalities remains largely unknown. Further research is needed to better understand the impact of these findings on growth, development, and treatment outcomes.

Infantile hydrocephalus: a review of epidemiology, classification and causes

Hydrocephalus is a common but complex condition caused by physical or functional obstruction of CSF flow that leads to progressive ventricular dilatation. Though hydrocephalus was recently estimated to affect 1.1 in 1000 infants, there have been few systematic assessments of the causes of hydrocephalus in this age group, which makes it a challenging condition to approach as a scientist or as a clinician. Here, we review contemporary literature on the epidemiology, classification and pathogenesis of infantile hydrocephalus. We describe the major environmental and genetic causes of hydrocephalus, with the goal of providing a framework to assess infants with hydrocephalus and guide future research.

Surgical correction of craniosynostosis. A review of 100 cases

PURPOSE

Provide outcome data for open cranial vault reshaping at a single institution by a single craniofacial surgeon treating 100 patients.

METHODS AND SUBJECTS

A total of 100 patient records were reviewed. Criteria for selection included patients less than three years of age undergoing primary surgery with open cranial vault reshaping and a minimum follow up time of 2 years.

RESULTS

Of the 100 patients (27 female, 73 male) treated 6 were syndromic and 94 nonsyndromic. Average age and weight were 8.9 months and 9.51 kg, respectively. The oldest child was 30 months and the youngest 5 months at the time of surgery. The estimated blood volume lost was 42.7% of total calculated blood volume ranging from 16.6% to 336%. Average surgical time was 216.7 min. Complications included 2 hematomas, 2 wound infections, 1 subgaleal abscess, 6 dural tears, 3 patients requiring reoperation for residual deformity, 4 cases requiring coronal scar revision, 1 sagittal sinus bleed, and 1 intraoperative death.

CONCLUSIONS

Our review of 100 open repairs of patients with craniosynostosis demonstrates good long-term results with an overall low complication rate. The outcome data will assist in developing future prospective studies aimed at improving the multidisciplinary care of these patients.

Craniocerebral disproportion: a topical review and proposal toward a new definition, diagnosis, and treatment protocol

INTRODUCTION

At some point in their lives, patients previously shunted for hydrocephalus may experience chronic, debilitating headaches, despite the fact that their shunts are functioning properly. Previously published reports have suggested that a subset of these patients may be suffering from an iatrogenic craniocerebral disproportion (CCD) and, therefore, may benefit from procedures that expand the available intracranial space. A unified definition of this disorder, however, is lacking.

DISCUSSION

Here, the authors chart the history (including historical terminology) of CCD, review its incidence, describe its signs, symptoms, and associated radiologic findings, and expound upon its pathophysiology. Next, a concise clinical definition of CCD based on the temporal correlation of headaches with the appearance of plateau waves on intracranial pressure (ICP) monitoring is proposed. The authors conclude with a discussion of the various therapeutic strategies employed previously to treat this disorder and present their individualized treatment strategy based upon the simultaneous utilization of ICP monitors and gradual external cranial vault expansion.

Successful treatment of post-shunt craniocerebral disproportion by coupling gradual external cranial vault distraction with continuous intracranial pressure monitoring

A subset of hydrocephalic patients in whom shunts are placed at an early age will develop craniocerebral disproportion (CCD), an iatrogenic mismatch between the fixed intracranial volume and the growing brain. The lack of a reliable, reproducible method to diagnose this condition, however, has hampered attempts to treat it appropriately. For those practitioners who acknowledge the need to create more intracranial space in these patients, the lack of agreed-upon therapeutic end points for cranial vault expansion has limited the use of such techniques and has sometimes led to problems of underexpansion. Here, the authors present a definition of CCD based primarily on the temporal correlation of plateau waves on intracranial pressure (ICP) monitoring and headache exacerbation. The authors describe a technique of exploiting continued ICP monitoring during progressive cranial expansion in which the goal of distraction is the cessation of plateau waves. Previously encountered problems of underexpansion may be mitigated through the simultaneous use of ICP monitors and gradual cranial expansion over time.

Craniosynostosis: Esthetic protocol in open technique

Introduction:

The past two decades have seen advances relative to the treatment of patients with craniosynostosis in the areas of resorbable fixation, imaging, and both intraoperative and perioperative management. The purpose of this study is to present open cranial vault reshaping techniques and anesthetic protocol used at Louisiana State University Health - Shreveport, USA.

Materials and Methods:

The surgical procedure of choice was single-stage open cranial vault reshaping with barrel-staving and orbital bandeau advancement as needed for supra-orbital rim deficiencies.

Results:

The outcomes of single-stage cranial vault reshaping with selective postoperative dynamic orthotics yielded symmetrical and consistent clinical results with only three children out of over 100 cases requiring later surgical correction.

Discussion:

Our review of techniques provides a safe protocol for management of craniosynostosis with symmetrical clinical head shape. The techniques presented here are aimed at improving the multidisciplinary management of these patients.

A review of hedgehog signaling in cranial bone development

During craniofacial development, the Hedgehog (HH) signaling pathway is essential for mesodermal tissue patterning and differentiation. The HH family consists of three protein ligands: Sonic Hedgehog (SHH), Indian Hedgehog (IHH), and Desert Hedgehog (DHH), of which two are expressed in the craniofacial complex (IHH and SHH). Dysregulations in HH signaling are well documented to result in a wide range of craniofacial abnormalities, including holoprosencephaly (HPE), hypotelorism, and cleft lip/palate. Furthermore, mutations in HH effectors, co-receptors, and ciliary proteins result in skeletal and craniofacial deformities. Cranial suture morphogenesis is a delicate developmental process that requires control of cell commitment, proliferation and differentiation. This review focuses on both what is known and what remains unknown regarding HH signaling in cranial suture morphogenesis and intramembranous ossification. As demonstrated from murine studies, expression of both SHH and IHH is critical to the formation and fusion of the cranial sutures and calvarial ossification. SHH expression has been observed in the cranial suture mesenchyme and its precise function is not fully defined, although some postulate SHH to delay cranial suture fusion. IHH expression is mainly found on the osteogenic fronts of the calvarial bones, and functions to induce cell proliferation and differentiation. Unfortunately, neonatal lethality of IHH deficient mice precludes a detailed examination of their postnatal calvarial phenotype. In summary, a number of basic questions are yet to be answered regarding domains of expression, developmental role, and functional overlap of HH morphogens in the calvaria. Nevertheless, SHH and IHH ligands are integral to cranial suture development and regulation of calvarial ossification. When HH signaling goes awry, the resultant suite of morphologic abnormalities highlights the important roles of HH signaling in cranial development.

Craniofacial reconstruction as a treatment for elevated intracranial pressure

INTRODUCTION

Craniofacial procedures may be needed to address symptomatic intracranial hypertension. The authors review their institutional experience in the treatment of children with symptomatic increased intracranial pressure (ICP) utilizing craniofacial reconstructive procedures.

METHODS

The senior authors' (HSM, SRC) craniofacial experience of 222 patients over a 7-year period from 2000 to 2007 at a single institution (Rady Children's Hospital, San Diego) is reviewed. Seventeen patients were identified who were felt to be candidates for craniofacial surgery with symptomatic increased ICP.

RESULTS

Patient diagnoses included single-suture craniosynostosis, craniofacial dysostoses, shunt-induced craniostenosis, and shunt-associated intracranial hypertension (slit-ventricle syndrome). Seventeen patients underwent 21 craniofacial procedures. Age at surgery ranged from 3 months to 13 years with a mean of 5 years. Preoperative symptoms and signs included headaches, unexplained irritability, seizures, papilledema, and visual loss. All patients had diagnostic neuroimaging. Seven patients had preoperative invasive ICP measurements. Surgery was deferred on three of these patients based on these measurements. The mean total operative (including anesthetic preparation) and surgical times were 3 h 12 min and 2 h 20 min, respectively. Percentage operative blood loss averaged 11.3%. In six procedures, no transfusions were required. Average hospital stay was 4 days. There was no perioperative mortality or significant surgery associated morbidity. All patients have had postoperative clinical improvement in signs and symptoms of increased ICP.

CONCLUSIONS

Using modern diagnostic and surgical techniques, including invasive ICP monitoring, increased intracranial pressure can be successfully managed by an experienced, multidisciplinary, craniofacial team. Our treatment paradigm and operative management scheme is discussed.

Resolution of syndromic craniosynostosis-associated Chiari malformation Type I without suboccipital decompression after posterior cranial vault release

Chiari malformation Type I (CM-I) is associated with syndromic and nonsyndromic craniosynostosis in pediatric patients, and the surgical management of CM-I in such cases is controversial. Previous guidelines have recommended simultaneous cranial vault expansion and suboccipital decompression. However, spontaneous resolution of CM-I has been observed, and the combined procedure carries additional surgical risks. The authors report the case of a 6-month-old boy with Crouzon syndrome, CM-I, and a cervical syrinx who underwent posterior cranial vault release without suboccipital decompression. Imaging at the 3-month follow-up visit demonstrated complete resolution of the CM-I, improvement in CSF flow, and reduction in the size of the syrinx. This case suggests that up-front suboccipital decompression may not be necessary in patients with craniosynostosis and CM-I. A strategy of initial cranial vault release, followed by watchful waiting and radiographic surveillance, is proposed.

Evaluation and management of nonsyndromic craniosynostosis

Craniosynostosis (craniostenosis) is premature fusion of the sutures of the cranial vault. Several factors can affect the growth of the cranial vault during embryonic life and after birth, leading to different types of craniosynostosis; these can be classified on the basis of the specific sutures that are fused. Prognosis is improved by early diagnosis, and it is important to establish the correct approach to these patients on the basis of clinical and neuroradiological investigation. The first priority is to identify the type of craniosynostosis and to distinguish between the types that require surgical intervention and those that do not. We report on the different forms of nonsyndromic craniosynostosis, their clinical and neuroradiological diagnoses, and surgical strategies.

CONCLUSION

The aim of this review is to provide to paediatricians a correct diagnostic approach and management of children affected from nonsyndromic craniosynostosis, for which a careful physical, ophthalmological and neurological examination is fundamental, whereas brain Computed tomography and magnetic resonance imaging are necessary for patients in which the diagnosis is uncertain or for cases of syndromic craniosynostosis.

Cranial vault expansion by distraction osteogenesis

OBJECT

The object of this report is to present a conceptual and technical approach for expanding the cranial vault, by distraction osteogenesis, in patients with craniocephalic disproportion secondary to pancraniosynostosis and in patients with complex syndromic craniofaciosynostoses undergoing operations for aesthetic improvement.

METHODS

The clinical characteristics, techniques used, outcome and complications for all patients who underwent cranial vault expansions with distraction osteogenesis in Children's Hospital of Denver were reviewed.

RESULTS

Twenty-six cranial vault expansions were done in 24 patients. Nineteen patients presented with intracranial hypertension. Twelve of these had pancraniosynostosis and 8 had a syndromic diagnosis. Large segments of cranial bone were translated in a controlled manner for distances up to 30 mm. All but one of the patients with intracranial hypertension experienced complete resolution.

CONCLUSIONS

Cranial vault expansion by distraction osteogenesis has the great advantage, as the name implies, of generating new and vascularized autologous bone of the correct shape and in correct locations. The technique, although not simple and not risk free, is much less technically complicated and places patients at lower risk for the most serious complications than does single-stage vault expansion. Less soft tissue dissection and less devascularization of bone are required and there are no postoperative dead spaces. Distraction osteogenesis facilitates far greater vault expansions than do single-stage procedures and can be accomplished in any desired direction.

Little evidence of association between severity of trigonocephaly and cognitive development in infants with single-suture metopic synostosis

OBJECTIVES

To measure severity of trigonocephaly among infants with single-suture metopic craniosynostosis by using a novel shape descriptor, the trigonocephaly severity index (TSI), and to evaluate whether degree of trigonocephaly correlates with their neurodevelopmental test scores.

METHODS

We conducted a multicenter cross-sectional and longitudinal study, identifying and recruiting 65 infants with metopic synostosis before their corrective surgery. We obtained computed tomography images for 49 infants and measured the presurgical TSI, a 3-dimensional outline-based cranial shape descriptor. We evaluated neurodevelopment by administering the Bayley Scales of Infant Development, Second Edition, and the Preschool Language Scale, Third Edition, before surgery and at 18 and 36 months of age. We fit linear regression models to estimate associations between test scores and TSI values adjusted for age at testing and race/ethnicity. We fit logistic regression models to estimate whether the odds of developmental delay were increased among children with more severe trigonocephaly.

RESULTS

We observed little adjusted association between neurodevelopmental test scores and TSI values, and no associations that persisted at 3 years. Trigonocephaly was less severe among children referred at older ages.

CONCLUSION

We observed little evidence of an association between the severity of trigonocephaly among metopic synostosis patients and their neurodevelopmental test scores. Detecting such a relationship with precision may require larger sample sizes or alternative phenotypic quantifiers. Until studies are conducted to explore these possibilities, it appears that although associated with the presence of metopic synostosis, the risk of developmental delays in young children is unrelated to further variation in trigonocephalic shape.