Nearly all children with spina bifida have Chiari II malformation.

• A. True
• B. False
• C. Not associated
• D. Rare

Answer: (A)

Chiari II malformation is almost always seen with open spina bifida, especially myelomeningocele, because the same early neurulation defect that creates the spinal lesion also disrupts hindbrain and CSF dynamics. In Chiari II, the cerebellar vermis and brainstem are pushed downward through the foramen magnum, often with aqueductal stenosis leading to hydrocephalus. This strong association means that in the typical population with open spina bifida, Chiari II is present in the vast majority, making the statement true. Spina bifida occulta or milder closed forms usually do not have Chiari II, which is why the association isn’t seen across all spina bifida cases. Recognizing this connection matters clinically because it guides imaging (often MRI) and prompts monitoring and management of hydrocephalus and brainstem-related symptoms.