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What is Chiari 2 malformation?

Chiari 1 Cerebellar tonsils protrude through the foramen magnum

Chiari 2 Cerebellum, brain stem and part of the IV ventricle protrude

Chiari 3 The above associated with an encephalocele

Chiari 4 Incompatible with life


Chiari 1

Often asymptomatic but may cause headaches with activities which increase the pressure in the brain . The headache is aggravated with coughing or sneezing. 2%-10% are associated with hydrocephalus and may lead to a syrinx (cavity within the spinal cord). Treatment is indicated only if symptomatic or causing a syrinx.

Treatment of a Chiari 1

If treatment is indicated, treatment progresses in a stepwise manner from least to most invasive. Any hydrocephalus is always treated first (with a shunt) followed by a bony foramen magnum decompression and then a cerebellar tonsillectomy if the bony decompression fails. Any syrinx is treated separately only if it fails to resolve with treatment of the Chiari.

Chiari 2

This condition is always associated with an open myelomeningocele (see spina bifida). It may present at birth with respiratory and feeding problems – possibly requiring urgent decompression. In early childhood the condition can cause bulbar problems (problems with feeding and drooling)

Treatment of Chiari 2

Surgical treatment remains controversial as the outcome is often so poor but when offered it is usually a cervical laminectomy.