What is a Chiari malformation?
A Chiari malformation is a defect at the back of the head where the brain connects to the spinal cord. This malformation is present at birth. There are four types of Chiari malformations. Type I and II are the most common.
Type I is the most common type and often goes unnoticed until adolescence or adulthood when problems begin to arise.
Type II is characterised by the back part of the brain shifting down through the bottom of the skull area. This presents at birth and is associated with spina bifida. It is also associated with hydrocephalus due to obstruction of CSF flow.
Type III is diagnosed when the back of the brain is seen to protrude from the back of the skull region.
Type IV is characterised by the back of the brain failing to develop normally.
Symptoms of a Type I Chiari malformation:
Patients can present with headaches. Numbness in the face and sensory loss over the shoulders with paraparesis can appear late in the course due to a condition where CSF flow diverts into the spinal cord resulting in a condition called a syrinx. Hydrocephalus is also associated with this condition as it obstructs the flow of CSF from the brain into the spinal cord.
Chiari malformation Surgery
Surgery is the only treatment option for Chiari malformation. There are a range of different surgery options so your surgeon will recommend the best option for your case. In some cases more than one surgery may be needed.
Posterior fossa decompression surgery can be performed on adults with Chiari malformation. This surgery aims to alleviate pressure in the spinal column by creating more space in the cerebellum. An incision is made at the back of the head and a small section of the skull is removed so as to correct the bone structure in this region. A spinal laminectomy may be performed as an alternate surgery. This surgery removes part of the lamina which results in more space for the spinal canal and less pressure on the spinal cord.
A shunt system that drains cerebrospinal fluid to relieve pressure can be used to treat individuals with hydrocephalus.