Sometimes the word "Chiari" comes up during an encephalocele evaluation, and parents understandably want to know what it means and how the two relate.
What Chiari malformation is
Chiari malformation is a condition where part of the lower brain (the cerebellum, and sometimes nearby structures) sits lower than usual, extending toward or into the space at the top of the spinal canal. There are different types, ranging from mild and sometimes symptom-free to more complex forms.
How it can relate to encephalocele
The connection is mostly relevant for posterior (back-of-head) and skull-base anatomy. One specific severe form, sometimes called Chiari III, involves herniation of posterior brain structures into a high cervical or occipital encephalocele. More commonly, the relevance is that families exploring posterior fossa anatomy may encounter Chiari as part of the broader picture, and the team evaluates the whole hindbrain region on MRI.
It's worth emphasizing that not every child with an encephalocele has a Chiari malformation, and not every Chiari malformation involves an encephalocele. The team looks at each child's specific MRI.
Why it matters
When Chiari-type anatomy is present, it can affect CSF flow (relating to hydrocephalus) and, in some forms, brainstem or spinal cord function. This influences monitoring and sometimes surgical planning. Mild forms may simply be watched; more complex forms need closer attention.
What evaluation involves
- MRI of the brain and the junction with the spine to define the anatomy
- Assessment for hydrocephalus and CSF flow
- Symptom monitoring (feeding, breathing, swallowing, movement), especially in more complex forms
- A coordinated plan between neurosurgery and the rest of the team
Sources
- StatPearls (NCBI Bookshelf) — Encephalocele / Chiari
- NINDS / NIH — Chiari Malformation
- CHOP — Encephalocele
- Cleveland Clinic — Chiari Malformation