Cranial Conditions

Chiari Malformation

Chiari Malformation

Chiari Malformation: when part of skull is deformed or too small, which puts pressure on brain and brainstem.

What is a Chiari Malformation?

A Chiari Malformation arises when the skull’s portion containing the cerebellum is malformed or undersized, exerting pressure on the brain and brainstem, pushing them beyond the spinal canal’s opening. This pressure on the cerebellum can manifest neurological symptoms. Furthermore, the displacement of the cerebellum into the upper spinal canal can disrupt cerebrospinal fluid flow, crucial for brain and spinal cord protection, leading to disruptions in normal brain-body signaling and potential fluid buildup in the spinal cord or brain.

What Causes Chiari Malformations?

The exact cause of Chiari malformation remains unknown, although it could be attributed to fetal developmental issues or exposure to harmful substances. Additionally, there might be a hereditary component. Chiari malformation presents in four types:

  • Type I: Typically seen in adults, this form is the most prevalent. Symptoms might not emerge until adulthood or adolescence, as it evolves with brain and skull growth, and it does not involve the brainstem.
  • Type II: Primarily congenital and prevalent in pediatric cases, it forces both the cerebellum and brainstem into the upper spinal canal. Often observed in infants with spina bifida, it can lead to complications like hydrocephalus.
  • Type III: This severe form entails not only the displacement of the cerebellum and brain stem but also protrusion of part of the fourth ventricle through the spinal canal opening, potentially causing significant neurological defects.
  • Type IV: In this type, the cerebellum fails to develop normally, possibly exhibiting missing parts or being positioned farther down the spinal canal.

Symptoms and Diagnosis

For Type I Chiari malformation, symptoms usually include headaches exacerbated by coughing, straining, or sneezing, along with neck pain radiating to the shoulders, gait and balance issues, numbness, tingling, and motor skill impairments. Additional symptoms may involve slurred speech, vision problems, swallowing difficulties, dizziness, tinnitus, bladder control issues, sleep apnea, chest pain, and spinal curvature.

Type II Chiari malformation symptoms may overlap with those of spina bifida due to more tissue displacement into the spinal canal.

Diagnosis involves thorough medical history assessment, developmental milestone inquiry, physical examination including head circumference measurement and back examination, and imaging tests like MRI or CT scans.


For asymptomatic or mildly symptomatic cases, observation and medication might suffice. However, severe cases necessitate surgical intervention to halt anatomical changes in the brain and spinal canal and alleviate symptoms. Surgeries typically involve decompression procedures such as spinal laminectomy or posterior fossa craniectomy, sometimes requiring multiple interventions.

Risks and Benefits

Failure to address spinal conditions preventively may exacerbate the condition. Surgical interventions for advanced cases can relieve extremity pain. Risks associated with surgery include common complications like infection, blood loss, non-union, and nerve or spine damage, along with specific risks related to the chosen treatment.

All information provided on this website is for information purposes only. Please see a healthcare professional for medical advice. If you are seeking this information in an emergency situation, please call 911 and seek emergency help.