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Before undergoing any surgical procedure, it is important to understand the risks and benefits of receiving treatment. If your doctor has recommended surgery for your Chiari malformation, he or she has already taken those risks and benefits into consideration. By understanding why that recommendation was made, you can feel confident in your decision and focus on other aspects prior to your upcoming surgery, such as preparing for your recovery.

About Chiari Malformation and Surgery Options

Several treatment options are available to treat your Chiari malformation. To better understand them, it is helpful to know a few things about your condition and how it developed.

As your body grows, your brain and skull form together, and the skull is shaped to perfectly encase and protect the brain. Sometimes, the skull does not grow sufficiently, and the inferior section of the brain, called the cerebellum, does not have enough room. Instead, a portion gets pushed out through a hole in the bottom of your skull, called the foramen magnum, where the spinal cord travels.

When this happens, there can be impingement on the cerebellum or spinal cord, and the fluid that flows around the spinal cord and brain (cerebrospinal fluid, or CSF) can be blocked. These effects lead to the symptoms that you experience with your Chiari malformation.

Chiari Malformation Surgical Procedures

The treatments for Chiari malformation all serve to help relieve this pressure by creating more room. There are two approaches: traditional surgical methods and minimally invasive procedures. Traditional surgical methods include:

  • Dural Opening Chiari Decompression: This is one of the most common Chiari malformation surgeries and has proven to be an effective treatment. During this procedure, the surgeon will make an incision at the base of your skull and remove a small section of the bone. The dura, or the delicate membrane covering your brain, will then be opened. The surgeon will then place a flexible patch, which can be made of natural or synthetic materials, providing more space for your cerebellum and helping relieve pressure. The incision site is closed with sutures or staples, which will be removed at a later follow-up visit.
  • Cervical Laminectomy: Your spinal cord is surrounded by the bony vertebrae of your spine, providing protection. The cervical vertebrae are those at the top of your spine, in the neck area. Sometimes it is necessary to remove a part of your uppermost vertebrae, a portion of the bone called the lamina, to create more space for your spinal cord. This procedure is often performed in conjunction with Chiari decompression surgery to create further space and prevent further damage to the spinal cord.
  • Spinal Fusion: You may have further craniocervical junction abnormalities that require extra stabilization of your spine. To achieve this, your surgeon is able to join the base of your skull with your uppermost vertebrae in a way that encourages them to heal together as a single bone, increasing stability in the area.
  • Transoral/Transnasal Decompression: Though rare, some patients have further malformations that require a different approach. By making a small incision within the nasal or oral cavity, the surgeon is able to reach and remove sections of bony malformations that are leading to your symptoms.
  • CSF Diversion: If there is a buildup of CSF (cerebrospinal fluid) within your skull or spinal cord as a result of your Chiari malformation, your surgeon may place a shunt, which will redirect the fluid to another area of the body, such as the abdomen, where it can be reabsorbed.

Minimally invasive procedures utilize special instruments and microscopic imaging, enabling the surgeon to make a smaller incision and disrupt less of the surrounding tissues. These advanced techniques commonly result in less bleeding, less pain and reduced healing time for patients.

Minimally invasive Chiari malformation treatments include:

  • Minimally Invasive Chiari Decompression: This procedure is similar to traditional dural opening Chiari decompression surgery, in that it helps to relieve pressure by creating more space at the back of the skull for your cerebellum. However, the incision made by the surgeon is much smaller, the opening in the dura is smaller, and the need for a patch is eliminated. Many patients who are candidates for traditional dural opening Chiari decompression surgery are also candidates for minimally invasive Chiari decompression surgery.
  • Non-Dural Opening Posterior Fossa Decompression: The posterior fossa is an area on the inside surface of your skull which houses the rearmost portion of your brain. By making a small incision at the back of your head, the surgeon is able to remove a small section of your skull, creating more space for your brain and spinal cord. This helps alleviate pressure and symptoms and prevent further damage.

Some patients require only one treatment method, while others need a combined approach to maximize results. Your surgeon will recommend what he or she feels best suits your individual situation, based upon the location and degree of your malformation, as well as any other complicating health conditions you may have.

If your doctor has not presented you with minimally invasive treatment options and they are something you are interested in, bring them up at your next appointment and find out why they have not been recommended. Not every surgeon specializes in these advanced techniques and you may wish to find one who does, should you be a candidate for them.

Chiari Malformation Surgery Risks

General Surgery Risks

As with any surgical procedure, risks are associated with Chiari malformation treatment. In general, risks universal to most neurosurgical procedures include:

  • Bleeding
  • Infection
  • Blood clots
  • Stroke
  • Nerve damage
  • Abnormal reactions to anesthesia

Specific Chiari Malformation Surgery Risks

Depending upon the treatment you receive, there are other specific Chiari malformation surgery risks. If your surgeon is performing minimally invasive decompression surgery, the risks are generally reduced compared to traditional decompression surgery. Because of technological advancements, the surgeon can make a smaller incision and use microscopic visualization and specialized instruments to perform the procedure and may avoid the need to place a patch.

Cerebrospinal Fluid Leakage

The first specific Chiari malformation surgery risk is the leakage of CSF. This occurs if the surgical repair of the membrane that covers the brain is not watertight. When this happens, the cerebrospinal fluid leaks out from the intracranial and intraspinal spaces, decreasing the pressure within the skull drops and can lead to headaches, nausea or clear fluid leaking from the ear, nose, or surgical incision thereby increasing the risk of infection.

This condition may resolve, without surgery, as long as it is confined to the space under the skin. Sometimes your doctor will have you drink more caffeine to help resolve the leak, and some patients may require a period of bed rest.


The second risk is essentially the opposite effect, where the pressure within the skull builds up because there is blockage of normal cerebrospinal fluid flow, a condition known as hydrocephalus. This can occur on a temporary basis, as a result of post-operative inflammation and is typically managed nonsurgically until it resolves. Persistent cases of hydrocephalus are treatable with a procedure where the surgeon places a shunt to drain the fluid, relieving the pressure. This is similar to the CSF diversion procedure described in the treatment section of the website.

Chiari Malformation Surgery Benefits

Although every patient experiences different results, most patients experience at least some reduction in symptoms. This includes relief from:

  • Headaches
  • Nausea and dizziness
  • Neck pain
  • Insomnia
  • Memory problems
  • Difficulty with swallowing or speaking
  • Numbness of face or hands
  • Problems with sight or vision

Your surgeon will give you a better idea of what exactly you can expect based on your individual condition. Be sure to discuss expected outcomes with your surgeon prior to your procedure.

How to Reduce Risks Before & After Chiari Malformation Surgery

Before your procedure, your surgeon will give you specific instructions to further reduce these risks, such as making modifications to your medications, diet and liquid intake. It is important to follow these guidelines to ensure the best possible outcome. These instructions will be tailored specifically for you and your situation and they are for your comfort and safety during the procedure.

Following surgery, the surgeon will also give you directions about any activity restrictions, medications and other steps you need to take during your recovery period. These are equally important and will help reduce the risk of complication following surgery. It can be frustrating to be told you cannot perform certain activities that you could before your surgery, but remember that these restrictions are to give your body time to heal following your procedure. Do not go beyond the limitations set by your doctor, even if you feel like you can. Healing is a process and it requires patience and rest.

Weighing Risks and Benefits

There are risks with any surgery, including Chiari malformation surgery, but there are also significant benefits. The overall risk of complications from these procedures is low, and prior to recommending treatment, your doctor takes these factors into consideration. Your preoperative discussion with your doctor should include a discussion of those risks and benefits prior to final decision making regarding surgery.

If surgery is recommended for you Chiari malformation, your surgeon feels that undergoing surgery will help stop the progression of and possibly alleviate the symptoms you are experiencing.

Making the decision to undergo surgery can be stressful, but accepted surgical procedures offer more benefit than potential risk. Now that you understand these risks and benefits, you can make an informed decision and focus on your recovery.

Chiari malformation treatments