Some Chiari malformations don't cause symptoms or affect a person's daily life. These malformations may not need any treatment.
For some symptoms, medicines may help. For example, pain medicines may help control headaches.
Your child's doctor may suggest avoiding actions, such as heavy lifting, that tend to bring on symptoms or make symptoms worse.
If your child's symptoms are ongoing (chronic) or can't be controlled with medicines or your child also has a cyst in their spinal cord (syringomyelia), your child may need surgery.
When deciding whether surgery might help your child, we consider:
- Your child's MRI (magnetic resonance imaging) findings.
- Your child's symptoms and whether they are getting worse. It helps us to know whatever you can tell us about the history of your child's symptoms.
- The doctor's exam of your child for signs of neurologic deficits.
- Whether your child has syringomyelia.
- Your opinion about whether to do surgery. Your child's doctor will talk with you in detail about the benefits and risks of surgery.
Together, you and your child's doctor will decide whether your child needs treatment and which type of treatment is best for your child.
Surgery for Chiari Malformations
Special MRI scans (cine-MRIs) of a child with a Chiari I malformation, before and after surgery. The arrow shows that cerebrospinal fluid (CSF) can't flow behind the lower back part of the brain (cerebellum) before surgery. Photo courtesy of the Chiari and Syringomyelia Foundation.
Our neurosurgeons do a surgery called posterior fossa decompression to treat Chiari malformations. It is the most common treatment for the condition.
The surgery makes more room in the skull for the cerebellum and brainstem. This relieves some pressure on the brain. The surgery also lets cerebrospinal fluid (CSF) flow in a more normal way, which may relieve some symptoms. If your child also has syringomyelia, this surgery usually lets the cyst drain so your child doesn't need surgery on the cyst itself.
Before surgery, your child may have an X-ray, a CT (computed tomography) scan or another MRI scan. These can give the neurosurgeon more details about your child's skull and neck and the best way to do surgery for your child.
There are many ways to do the surgery, based on your child's condition and the neurosurgeon's experience. Here is an overview of the options.
Removing bone from the skull
During the surgery, the neurosurgeon makes a cut (incision) at the back of your child's head and removes a small piece of bone from the base of your child's skull. This step makes the normal hole in the base of the skull (foramen magnum) bigger so there's more room for the brain, spinal cord and CSF. The back of your child's skull is called the posterior fossa. The base where the bone is removed is called the suboccipital area. Taking out the bone here is called suboccipital craniectomy.
Removing bone from the neck
The surgeon may also need to remove the back part of the first bone of the spine (first cervical vertebrae or C1) to make enough room for your child's brain. Taking out the back of this bone is called C1 laminectomy. Some children who have surgery need only suboccipital craniectomy and C1 laminectomy.
Opening the membrane over the brain
Where the bone was removed from the skull, the surgeon may open up the tough membrane (dura mater) that covers your child's brain. Opening up the membrane (intradural surgery) makes more room for CSF to flow. Not all children who have surgery need this step.
Shrinking the cerebellum
With the membrane open, the surgeon may use a method to make the bottom parts of the cerebellum (cerebellar tonsils) smaller. At Seattle Children's, we do not destroy or cut out (resect) any of the cerebellum. We sometimes use electrocautery - a way to shrink the cerebellar tonsils by touching them with a tool that is heated by an electric current. Shrinking the cerebellar tonsils makes more room for CSF.
Patching the membrane
If the membrane was opened, the surgeon closes and protects the area by sewing a patch on it. The patch usually comes from tissue that's deep under your child's scalp but outside your child's skull (pericranium). This tissue makes a good patch because your child's body is likely to accept the tissue, and it's less likely to leak than some other types of patches. Other options include taking tissue from some other part of your child's body (the covering of a neck muscle or a strong band of tissue from their leg, called fascia lata) or using a synthetic patch.
Finally, the neurosurgeon brings the skin back together and closes the incision.
The arrow points to white space where CSF can flow after surgery. Photo courtesy of the Chiari and Syringomyelia Foundation.
The main concern for most children and families right after surgery is pain. We will give your child medicine to help with pain and relax their muscles so they are comfortable while they heal. We do this in a way that is comforting both to the child and to their family. Often children do not remember much about this healing time.
If your child has a pericranial patch in the back of their head that is in contact with CSF, they might have swelling (inflammation) called aseptic meningitis. (This reaction is not an infection.) If needed, we will give your child steroids to decrease the inflammation. If your child's dura mater was not opened during surgery, they are not likely to need steroids.
In most children, symptoms of a Chiari malformation start to improve during the first month after surgery. If we recommend surgery, it means we expect the benefits to outweigh the risks. But there are still some risks to having the surgery. Sometimes some symptoms remain. Other risks of the surgery include leaking CSF, hydrocephalus, neurological issues, reaction to the pericranial patch or infection.
Your neurosurgeon will talk with you and your child about staying away from certain activities, like heavy lifting and contact sports, for at least a few months while your child heals. During this time, it's important for your child not to strain their neck.
Follow-up care is important to watch for any symptoms that come back or get worse. Your child will also need MRIs to check their condition as their skull keeps growing.
When an experienced neurosurgeon does the surgery, the results are often quite good. But a Chiari malformation is a complex condition, and many children need careful follow-up. It takes an entire healthcare team to provide high-quality, coordinated care throughout life for a child with a Chiari malformation.