Brain structure in sagittal craniosynostosis

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.

Predicting calvarial morphology in sagittal craniosynostosis

Early fusion of the sagittal suture is a clinical condition called, sagittal craniosynostosis. Calvarial reconstruction is the most common treatment option for this condition with a range of techniques being developed by different groups. Computer simulations have a huge potential to predict the calvarial growth and optimise the management of this condition. However, these models need to be validated. The aim of this study was to develop a validated patient-specific finite element model of a sagittal craniosynostosis. Here, the finite element method was used to predict the calvarial morphology of a patient based on its preoperative morphology and the planned surgical techniques. A series of sensitivity tests and hypothetical models were carried out and developed to understand the effect of various input parameters on the result. Sensitivity tests highlighted that the models are sensitive to the choice of input parameter. The hypothetical models highlighted the potential of the approach in testing different reconstruction techniques. The patient-specific model highlighted that a comparable pattern of calvarial morphology to the follow up CT data could be obtained. This study forms the foundation for further studies to use the approach described here to optimise the management of sagittal craniosynostosis.

Impaired hippocampal development and outcomes in very preterm infants with perinatal brain injury

Preterm infants are at high risk for brain injury during the perinatal period. Intraventricular hemorrhage and periventricular leukomalacia, the two most common patterns of brain injury in prematurely-born children, are associated with poor neurodevelopmental outcomes. The hippocampus is known to be critical for learning and memory; however, it remains unknown how these forms of brain injury affect hippocampal growth and how the resulting alterations in hippocampal development relate to childhood outcomes. To investigate these relationships, hippocampal segmentations were performed on term equivalent MRI scans from 55 full-term infants, 85 very preterm infants (born ≤32 weeks gestation) with no to mild brain injury and 73 very preterm infants with brain injury (e.g., grade III/IV intraventricular hemorrhage, post-hemorrhagic hydrocephalus, cystic periventricular leukomalacia). Infants then underwent standardized neurodevelopmental testing using the Bayley Scales of Infant and Toddler Development, 3rd edition at age 2 years, corrected for prematurity. To delineate the effects of brain injury on early hippocampal development, hippocampal volumes were compared across groups and associations between neonatal volumes and neurodevelopmental outcomes at age 2 years were explored. Very preterm infants with brain injury had smaller hippocampal volumes at term equivalent age compared to term and very preterm infants with no to mild injury, with the smallest hippocampi among those with grade III/IV intraventricular hemorrhage and post-hemorrhagic hydrocephalus. Further, larger ventricle size was associated with smaller hippocampal size. Smaller hippocampal volumes were related to worse motor performance at age 2 years across all groups. In addition, smaller hippocampal volumes in infants with brain injury were correlated with impaired cognitive scores at age 2 years, a relationship specific to this group. Consistent with our preclinical findings, these findings demonstrate that perinatal brain injury is associated with hippocampal size in preterm infants, with smaller volumes related to domain-specific neurodevelopmental impairments in this high-risk clinical population.

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Perinatal brain injury is related to smaller hippocampal volumes in preterm infants

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Infants with high-grade intraventricular hemorrhage have smallest hippocampi

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Larger ventricular size is related to smaller hippocampal volumes in hydrocephalus

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Smaller hippocampi are related to worse cognitive outcomes in brain injured infants

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Smaller hippocampal volumes associated with worse motor performance across groups