Macquiarie Neuro Surgery & Spine
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Chiari Malformation

Some patients with Chiari malformation have no symptoms. For others, the condition may lead to serious complications.

Patients with Chiari malformation require management by an experienced neurosurgical team. Specialists at Macquarie Neurosurgery & Spine are some of Australia’s leading experts on this condition and its complications. 

What is Chiari malformation? 

Chiari malformation is a structural abnormality that forms during foetal development.

The cerebellum is the back part of your brain, and it coordinates balance and movement. Normally, the cerebellum is found within your skull. In patients with Chiari malformation, part of the cerebellum is squeezed out into the upper spinal canal.


Chiari malformation can block the normal flow of CSF between the brain and spinal cord, causing increased pressure on these structures.


There are four different types of this condition. People with Chiari malformation type I may or may not experience symptoms. Type II Chiari malformation is generally more severe and is often associated with myelomeningocele (a type of spina bifida that causes paralysis in the legs). Types III and IV are rare. When they do occur, they cause severe problems from infancy and are often associated with other serious congenital defects.


What are the symptoms of Chiari malformation?

Chiari malformation is closely linked with syringomyelia.

Syringomyelia is the formation of cysts in the spinal cord. It can cause a wide range of symptoms, but typically leads to muscle weakness or sensation loss in the upper body, arms, and hands.


Other symptoms of Chiari could include:


  • Severe head and neck pain (often made worse by straining, sneezing, or coughing)
  • “Drop attacks” (sudden collapse caused by muscle weakness)
  • Dizziness or balance problems
  • Spasticity (abnormally stiff muscles)
  • Visual disturbances (like double or blurred vision, or hypersensitivity to bright lights)
  • Sleep apnoea

Some patients with Chiari malformation also have spinal deformities like scoliosis. Patients with type II Chiari may develop hydrocephalus, a serious condition caused by excess CSF within the ventricles (cavities) of the brain.


Not all patients with Chiari malformation develop symptoms. Quite frequently, the condition is found incidentally when brain imaging is done for other reasons.

How is Chiari malformation treated?

Treatment of Chiari malformation (and associated syringomyelia) is dependent on the type of malformation and its symptoms.


If the malformation is not causing any symptoms, and has not led to syringomyelia, treatment may not be necessary. If there are symptoms, surgery may be considered to relieve pressure on the spinal cord and lower part of the brain, and to restore normal CSF flow.


Decompression surgery involves removing a small part of the base of the skull, as well as the back part of the first few neck vertebrae. A tissue graft (usually taken from the patient) may be used to further widen the canal. If there is a syrinx within the spinal cord, it may require drainage with a shunt.


The management of Chiari malformation is specialised and highly complex. For over 20 years, research by the team at Macquarie Neurosurgery & Spine has contributed to advances in the management of this condition. Our neurosurgical team is committed to evidence-based care that optimises patients’ health outcomes.    


You can arrange a consultation with us, at one of our NSW or ACT locations, by calling us on 02 9812 3900. Alternatively, you can request an appointment via our enquiry form.