About Chiari Malformations
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Chiari malformations are structural defects that affect tissue in the brainstem, cerebellar (the area of the brain at the back of the skull), and spinal cord. They can cause symptoms ranging from headaches and muscle weakness to developmental delays and breathing problems. Typically, they occur in the area where the brain and spinal cord meet. In most cases, parts of the brain push down into the spinal canal and cause pressure in the brain and on the spinal cord. This often blocks the flow of cerebrospinal fluid (CSF), which can cause fluid-filled cysts on the spinal cord (called syringes) and hydrocephalus (a buildup of fluid in the brain). There are four types of Chiari malformations. Types I and II are more common, while types III and IV are rare.
Type I is the most common and can go undiagnosed until symptoms develop during childhood, adolescence, or even into adulthood. This type can cause syringomyelia (when syringes form on the spinal cord). This can cause paralysis, weakness, and stiffness in the back and limbs. Scoliosis (spine curvature) is often associated with this type.
Type II typically affects children born with spina bifida, specifically infants with myelomeningoceles -- spinal cord tissue that protrudes through an opening in the spine.
Type III is a rare and very serious form of Chiari malformation. Some parts of the brain may stick out, or herniate, through an abnormal opening in the back of the skull.
Type IV is very rare. In this type, part of the brain is underdeveloped or missing.
Diagnosing Chiari Malformations
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Duke Children’s pediatric neurosurgeons combine clinical evaluation with advanced testing to fully understand your child’s condition and recommend the right level of care for type I and type II Chiari malformations.
Type I Chiari Malformations
For type I Chiari malformations, we conduct a thorough medical history and physical examination, including a review of family history to look for a possible genetic cause. We also perform a detailed neurological assessment of your child. A sudden headache when coughing, sneezing, or laughing -- anything that causes pressure in the head -- is one of the most common symptoms.
Type II Chiari Malformations
For type II malformations occurring with spina bifida, we collaborate with your child’s neurologist and otolaryngologist (an ear, nose, and throat specialist) to check for evidence of brainstem dysfunction.
Imaging Tests
We may recommend imaging tests, such as MRI or CT scans, to confirm the diagnosis. A special type of MRI -- a cine MRI scan or CSF flow study -- will show the flow of cerebrospinal fluid and help determine whether it’s building up in the brain or spine.
Treatments for Chiari Malformations
Treatments Overview
Our pediatric neurosurgeons collaborate with specialists who care for children with conditions associated with Chiari malformations. Your child's care team may include an orthopedic surgeon if scoliosis is involved, or a neurologist if your child was born with spina bifida or recently developed symptoms from a type I Chiari malformation. These specialists will continue to monitor your child's progress to ensure effective treatment.
Monitoring
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If your child’s symptoms are minor, we may recommend monitoring the Chiari malformation with periodic imaging as your child grows. In younger children, a Chiari malformation may actually improve on its own, and surgery may not be needed.
Headache Medication
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If a Chiari malformation is causing headaches as the only symptom, pain medication may be all that is needed.
Shunt Placement Surgery and Shunt Repair Surgery
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Often, symptoms of a type II Chiari malformation can be relieved by placing a shunt -- a device that helps divert excess fluid away from the brain due to hydrocephalus -- or repairing a malfunctioning shunt. A shunt consists of two long, flexible tubes (catheters) and a valve joining them. One end of the shunt is placed into the part of your child’s brain where there is too much fluid. The other end drains the fluid to another area in the body. If your child has a shunt that is no longer working, it can make Chiari malformation symptoms worse. Shunt repair may be all that is needed.
Decompression Surgery
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When symptoms become severe and affect your child’s ability to function, surgery can help. Decompression surgery removes bone to create more space around the lower brain and upper spine. This relieves pressure on the spinal cord and halts further damage. Depending on your child’s condition and circumstances, the surgeon may consider also opening the dura (a membrane that surrounds the brain and spinal cord) and inserting a patch to further expand the space. Decompression surgery also restores the normal flow of spinal fluid.
Syringomyelia Surgery
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Syringomyelia is typically treated with decompression surgery. Rarely, surgery may not eliminate the syrinx (a fluid-filled cyst within the spinal cord). In those cases, a pediatric neurosurgeon can insert a shunt to drain the cyst and relieve pressure. This may improve scoliosis if it is caused by the cyst and eliminate the need for or postpone more invasive scoliosis surgery.
