Nonsynostotic Posterior Brachycephaly with Hindbrain Herniation.

Area of Science:

• Pediatric Neurosurgery
• Developmental Pediatrics
• Cranial Morphology

Background:

• Positional plagiocephaly is a common cause of infant cranial asymmetry.
• Chiari-1 malformation theories are diverse, with anecdotal links to severe positional brachycephaly.
• No prior cases have documented nonsynostotic plagiocephaly with Chiari-1 malformation.

Observation:

• An 18-month-old boy with head trauma presented with significant posterior brachycephaly.
• Imaging revealed an acute subdural hematoma and incidentally, positional plagiocephaly.
• Further MRI showed a small posterior fossa with cerebellar tonsil herniation, indicative of Chiari-1 malformation.

Findings:

• This is the first reported case linking nonsynostotic deformational plagiocephaly with Chiari-1 malformation.
• The study hypothesizes that severe positional plagiocephaly may lead to posterior fossa disproportion and acquired hindbrain herniation.
• The co-occurrence of these common conditions could also be coincidental.

Implications:

• This case raises awareness of a potential causal relationship between positional plagiocephaly and acquired Chiari-1 malformation.
• It highlights the importance of considering posterior fossa abnormalities in infants with severe positional head deformities.
• Further research is warranted to explore the putative link between cranial shape and hindbrain herniation.