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Unicoronal Craniosynostosis: Is There a Lateral Difference in Retinal Morphology?
Christopher L Kalmar1, Anna R Carlson1, Zachary D Zapatero1
1Division of Plastic and Reconstructive Surgery, Children's Hospital of Philadelphia.
Insights
In pediatric craniosynostosis, elevated intracranial pressure is not uniform. Retinal nerve fiber layer thickness shows a rotational pattern, suggesting differential pressure transmission or retinal morphology changes.
Area of Science:
- Pediatric Neurosurgery
- Ophthalmology
- Cranial Surgery
Background:
- Craniosynostosis involves premature cranial suture fusion in children, potentially causing elevated intracranial pressure.
- The distribution of this increased intracranial pressure within the cranial vault is not fully understood.
Purpose of the Study:
- To investigate the localized effects of intracranial pressure in pediatric craniosynostosis.
- To determine if elevated intracranial pressure is uniformly distributed or localized near fused sutures.
Main Methods:
- Utilized Optical Coherence Tomography (OCT) for noninvasive measurement of peripapillary retinal nerve fiber layer (RNFL) thickness.
- Compared RNFL thickness in eyes ipsilateral versus contralateral to unicoronal suture fusion in pediatric patients.
Main Results:
- Analyzed 21 pediatric patients undergoing surgical correction for craniosynostosis.
- Observed a 45° circumferential rotation in RNFL thickness patterns, indicating a 'rotation phenomenon' rather than a simple increase on the affected side.
- This rotation was observed in the direction of intorsion.
Conclusions:
- The observed RNFL changes suggest differential transmission of intracranial changes to the peripapillary retina.
- Alternatively, differing retinal morphology between ipsilateral and contralateral eyes may explain the findings.
- Further research is needed to elucidate the exact mechanisms behind these observed phenomena.
Background:
Craniosynostosis is the premature fusion of cranial sutures in pediatric patients, which may lead to elevated intracranial pressure due to cerebro-cephalic disproportion between a growing brain and constricted skull. It is unknown whether this increased pressure is distributed equally throughout the cranial vault, or whether certain areas of the brain experience greater pressure at these regions of premature osseous fusion.
Methods:
Optical coherence tomography (OCT) is a noninvasive modality for detecting elevated intracranial pressure. Optical coherence tomography was utilized to measure the peripapillary retinal nerve fiber layer (RNFL) thickness in patients undergoing surgical correction of craniosynostosis. Retinal nerve fiber layer in the eye ipsilateral to the unicoronal suture fusion was compared to the RNFL in the eye contralateral to the unicoronal suture fusion.
Results:
During the study interval, 21 patients met inclusion criteria. Median age at operative intervention was 8.0 months, and 28.6% patients presented with left-sided unicoronal craniosynostosis, whereas 71.4% of patients presented with right-sided unicoronal craniosynostosis. Rather than universal increase on the affected side of coronal suture fusion, retinal nerve fiber layer thickness parameters showed a rotation phenomenon, such that the patterns of elevation had a 45° circumferential rotation in the direction of intorsion.
Conclusions:
The explanation for these results remains elusive, but they likely indicate either intracranial changes transmitted differentially to the peripapillary retina, or differing retinal morphology, between the ipsilateral and contralateral eyes in unicoronal craniosynostosis.
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