Chiari Malformation

Chiari (pronounced: key-AR-ee) malformations are a group of conditions that result when a portion of the cerebellum (back part of the brain) grows outside of the skull and into the spinal canal. At Nemours Children’s Health System, our pediatric neuroscience teams are experts at recognizing the different signs and symptoms of Chiari malformations in children and providing effective, appropriate care. In fact, our pediatric neurosurgeons, neurologists and neuroradiologists are leading the way in developing best practice protocols and technologies — both medical and surgical options — to successfully diagnose and treat children with Chiari malformations.

Read More About Chiari Malformations in Children

A Chiari malformation is a general term for a group of conditions that result when the skull at the back of the head is too small or malformed and crowds the cerebellum (the back portion of the brain). When this happens, there is increased pressure on the brain and parts of the cerebellum (and sometimes the brainstem and other structures) extend or protrude downward through a hole in the skull (called the "foramen magnum") and typically into the spinal canal (the upper part of the spinal cord).

Types and Causes of Chiari Malformations

Chiari malformations can be congenital (present at birth) or acquired (occur over time). There are different types of Chiari malformations, from Type I (a milder form that may not require treatment) to Type IV (a very rare and severe congenital form caused by a malformed cerebellum).

There is no one cause of Chiari malformations, however it’s believed the condition is tied to problems during fetal development. These problems may occur due to genetic mutations (or changes) while the baby is still in the womb, congenital medical conditions (like spina bifida), nutritional deficiencies and other causes that are currently being researched.

Symptoms and Treating Chiari Malformations in Children

Chiari malformations symptoms can present at any age, and in milder forms (like Type I Chiari malformation), there may be no symptoms at all. In some cases, symptoms may begin in late childhood to early adulthood. Symptoms of Chiari malformations can include:

  • occipital headaches (at the back of the brain) that may worsen upon straining, coughing/sneezing or physical activity
  • dizziness and/or vertigo (balance problems)
  • vision problems (blurriness or involuntary eye movements)
  • problems swallowing
  • respiratory problems (like sleep apnea/obstructed breathing)
  • muscle weakness
  • tingling and/or numbness in the hands or feet
  • impaired fine motor skills (cutting, writing, tying shoes)
  • tinnitus (ringing in the ears)
  • chronic fatigue
  • loss of bowel or bladder function
  • spasticity (rigid or tight muscles)

Treating Chiari malformation involves alleviating the symptoms it causes and if appropriate, surgically repairing the malformation to reduce the pressure on the brain. Neurosurgery is not always necessary, particularly when there are no symptoms present. When surgical treatment (like posterior fossa decompression) is required, most children with less severe types do very well and grow up being active kids and independent adults.

Why Families Choose Nemours

Families choose Nemours because we’re wholly dedicated to building strong partnerships and providing family-centered care. Our team might know your child’s condition, but only you know your child best. We want you to be an active participant in the decision-making process, which is why we take the time to explain the diagnosis and treatment in understandable terms, present all of the options and invite your input to create the right treatment plan for your child.

We always take time listen to your concerns and provide personal service and comprehensive care for your child — and family — through emotional support, education and open communication.

Learn More About Why Families Choose Us »

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Nemours/Alfred I. duPont Hospital for Children, Wilmington

1600 Rockland Road
Wilmington, DE 19803
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For Appointments: (302) 651-4200

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  • photo ID
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  • names and dosage of all medications, including over-the-counter medication, your child is currently taking
  • guardianship and custody papers, if a legal guardian rather than a parent accompanies your child
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    Note: A parent or legal guardian must be with a child for a first visit.
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The neurosurgeons at Nemours/Alfred I. duPont Hospital for Children provide expert care for children and teens with Chiari malformations. As part of the Nemours Neuroscience Center, our renowned neurosurgeons work together with a multidisciplinary (multiple specialties) team to appropriately diagnose Chiari malformations. Our goal is to improve your child’s quality of life, using proven treatments with the least amount of side effects.

Learn More About Neurosurgery at Nemours/Alfred I. duPont Hospital for Children »

Highlights of Our Pediatric Neurosurgery and Neurology Care

Families from across the country and around the globe come to Nemours/Alfred I. duPont Hospital for Children in Wilmington, Del., because of our comfortable, technologically advanced facility and our pediatric specialists and surgeons who are consistently recognized among the very best in clinical care.

Highlights of our pediatric neurosurgery care include:

  • world-class facilities featuring the most advanced diagnostic techniques and equipment available
  • academic medical center (which means we’re at the leading edge of treating highly complex neurosurgical conditions)
  • fully-equipped neurosurgery operating rooms
  • innovative surgical techniques that minimize surgery risks, recovery time and pain
  • extensive imaging and navigational equipment for precise instrument guidance
  • customized treatment plans based on research and best practices
  • care without delay (which means you have seamless, rapid access to specialists)  
Chiari Malformation Symptoms in Children

In addition to the most common symptom of Chiari, the classic occipital (back of the head) headache, there are many other symptoms that can be severe. Other Chiari malformation symptoms in children and adolescents may include:

  • dizziness
  • balance problems
  • nausea or vomiting
  • visual disturbances (nystagmus or involuntary eye movement, blurry vision)
  • hearing problems
  • feeding and/or swallowing problems
  • respiratory (breathing) problems
  • sleep apnea (obstructed breathing)
  • muscle weakness (face and/or extremities)
  • chronic pain (head, neck)
  • tingling and/or numbness in the hands or feet
  • fine motor skill problems (manipulating objects such as scissors, pencils, etc.)
  • tinnitus (ringing in the ears)
  • chronic fatigue
  • loss of bowel or bladder function
  • spasticity (rigid or tight muscles)
  • scoliosis

We work closely with pediatric specialists across medical disciplines who can prescribe medicines and therapies to alleviate these symptoms.

Learn More About Chiari Malformations and Related Topics From Nemours’ »

Your Child’s Chiari Malformation Treatment Team

Your child’s coordinated medical team at Nemours/Alfred I. duPont Hospital for Children is lead by renowned board-certified pediatric neurosurgeons, neurologists and neuroradiologists who, along with registered nurses, physician assistants and certified health providers (social workers and Child Life specialists) are experienced in the physiological and psychological changes that occur as children grow and develop. We also work closely with pediatric specialists at the hospital to treat conditions that may be related to, or caused by, Chiari malformations.

Your child’s care team may include pediatric:

Because of our award-winning electronic health record system, our experts at Nemours/Alfred I. duPont Hospital for Children can instantly consult with Nemours experts throughout our children’s health system in order to pool our resources. That allows us to offer your child the best Chiari malformations care, no matter how complex the condition.


Chiari Malformations in Babies and Children

Chiari malformations are structural abnormalities in the back of the head that impact the cerebellum, or the part of the brain responsible for movement, balance and muscle control. In the most common form of Chiari (Type I) overcrowding in this area causes the "tonsils" located at the bottom part of the cerebellum to protrude (or "herniate") into a hole in the opening at the base of the skull where the spinal cord is. This is often referred to as "tonsillar herniation."

In other types of Chiari, the cerebellum tonsils, the brainstem and sometimes the fourth ventricle (where cerebral spinal fluid, or "CSF," flows at the base of the skull) displace the spinal cord, which can lead to complex medical problems.

Types, Causes and Complications of Chiari Malformations

Chiari malformations in children can be present at birth (congenital) or occur over time (acquired), and can form because of a genetic change during fetal development, a congenital medical condition (like spina bifida) or other causes we do not fully understand.

Types of Chiari Malformations in Babies and Children

Type I

Sometimes referred to as "tonsillar herniation" (or "tonsillar ectopia"), this type occurs when the cerebellum tonsils (bottom part of the cerebellum) protrude into the upper part of the spinal canal and displace the spinal cord. Chiari malformation Type I is the mildest form that may or may not require surgical treatment. If the condition is causing problems, surgery may be recommended. But many children have this type of Chiari malformation without any symptoms and can just be followed.

Type II

Often referred to as "Arnold-Chiari malformation," Type II Chiari is mainly seen in infants with myelomeningocele (a type of spina bifida, or a disorder caused by the spinal cord not closing properly during development). This type of Chiari occurs when the cerebellum and brainstem (and often the fourth ventricle of the brain) push downward into the spinal canal. Arnold-Chiari malformation Type II can also cause hydrocephalus due to accumulation of "fluid on the brain."

Type III and Type IV

These are very rare forms that cause defects in the brain and spinal cord. Type III results when parts of the cerebellum and brainstem protrude out of the skull or neck and Type IV is caused by the improper cerebellum development.

Causes of Chiari Malformations

There is no one cause for the structural defects in the brain and skull that cause Chiari malformations but we understand that certain things may contribute, such as:

  • genetic mutations or changes (certain genetic changes that may increase the risk for the condition)
  • lack of nutrients in the diet (B vitamins/Folate, folic acid among others)
  • exposure to hazardous chemicals and substances
  • maternal alcohol or drug use
  • certain congenital conditions (spina bifida, craniosynostosis, others)
  • trauma (either from injury or previous brain surgery)
  • infection (meningitis)
Chiari Malformation Complications and Related Conditions

Some types of Chiari malformations can restrict the flow of cerebrospinal fluid, or "CSF," in the ventricular system (the four cavities in the brain where CSF is produced and continuously circulated). Cerebral spinal fluid is important for protecting and nourishing the brain and spinal cord and when blocked, can result in hydrocephalus (fluid accumulation and head swelling).

Also, when the cerebral spinal fluid is blocked by a Chiari malformation, a fluid-filled cyst in the spinal cord can develop called a "syrinx" causing syringomyelia, a condition that, like hydrocephalus, can lead to neurological dysfunction if untreated.

Other conditions that are related to Chiari include:

Symptoms of Chiari Malformations

Chiari malformations affect the nervous system and can cause a wide variety of symptoms that appear differently in different children. Although some Chiari malformations cause no symptoms at all, symptoms can slowly occur over time or may present in late adolescence and early adulthood.

The main indicator of Chiari is a severe headache at the back of the head that’s brought on (or worsened) by straining such as when coughing, sneezing, laughing or exercising.

Our Approach to Caring for Kids With Chiari Malformations

At Nemours/Alfred I. duPont Hospital for Children, our neuroscience team provides conservative, comprehensive and compassionate evaluation and treatment for infants, children and teens with Chiari malformations, particularly Types I (tonsillar herniation) and II (Arnold-Chiari malformation).

Many times, Chiari is diagnosed incidentally (or during diagnostic imaging for a different condition) because children do not experience symptoms. In these cases, Chiari doesn’t require treatment. However, when symptoms are severe and neurological problems occur, we can successfully surgically treat Chiari, and these children go on to lead productive lives and, depending on their condition, with little or no cognitive affects.

Chiari Evaluation and Diagnosis at Nemours/Alfred I. duPont Hospital for Children

During your child’s first visit, our neurosurgical team will evaluate your child’s medical history and symptoms, perform a complete neurological exam, address your child’s immediate needs, and develop a plan for further testing and treatment.

And because Chiari malformations can be associated with other conditions, your child’s care team may order additional diagnostic tests. Once we have all of this information, we’ll work together with your family to create a personalized treatment plan that may include watchful waiting, medicines to treat symptoms or neurosurgery to repair the Chiari malformation.

Diagnostic Testing for Chiari Malformations in Children

Radiology (Medical Imaging) Tests

  • ultrasound (look for signs of hemorrhage)
  • CT or "CAT" scan/computed tomography (view the ventricles and other structures)
  • MRI/magnetic resonance imaging (look for tumors or malformations at the neck and head)
  • CINE, pronounced "sin-nee," MRI (assess cerebrospinal fluid flow in the ventricles)
  • cranial X-rays (view the skull bones)

Nemours/Alfred I. duPont Hospital for Children radiology department has highly technical 3-D (three-dimentional) capabilities. This means better diagnostic imaging with less exposure to radiation.

Learn More About Radiology (Medical Imaging) at Nemours/Alfred I. duPont Hospital for Children »

What’s more, Chiari malformations can sometimes be diagnosed in utero, or while the baby is in the womb, through our Nemours Partners for Perinatal Management program.

Learn More About Fetal Diagnostic Testing at Nemours/Alfred I. duPont Hospital for Children »

Other Tests Children With Chiari Malformations May Need

Depending on the condition, the team may recommend additional tests and procedures to diagnose related problems, including:

  • evoked potentials testing (measures brain activity given auditory, visual and sensory stimuli including auditory brainstem response, or "ABR"; visual evoked response, or "VER"; and somatosensory evoked potential, or "SEP")
  • ophthalmological exam (evaluates potential problems in and around the eyes)
  • otolaryngology exam (examines balance and potential ear, nose and throat disorders)
  • polysomnography or "sleep study" (evaluates sleep disorders like sleep apnea)
  • urological testing (urodynamic testing)
  • ongoing assessments for neurological, intellectual or developmental delays

Pediatric Chiari Malformation Treatment

Although surgery is the only treatment for Chiari malformations in children, the condition may not require treatment at all. At Nemours/Alfred I. duPont Hospital for Children, we customize treatment plans that may include conservative watchful waiting (no treatment with regular check-ups to monitor the condition), medicines and therapies to reduce symptoms (such as headaches or vestibular/balance problems) and neurosurgery to provide space for the cerebellum and normalize the pressure on the brain. Other treatments may be necessary to manage an underlying condition that’s related to the Chiari malformation (such as hydrocephalus or tethered spinal cord).

Our neuroscience team works closely with top Nemours specialists in other medical disciplines to ensure your child receives the best care possible.

Learn More About Hydrocephalus Treatment at Nemours/Alfred I. duPont Hospital for Children »

Surgical Treatment at Nemours/Alfred I. duPont Hospital for Children

The goals of surgical treatment for kids with Chiari malformations are based on the symptoms and how they affect a child’s quality of life. Surgery for Chiari malformation Type I is intended to give the cerebellum enough space, reduce the pressure on the brain, and restore normal cerebral spinal fluid flow in the ventricular system. Surgery is more likely when children have syringomyelia (or a fluid-filled cyst in the spinal cord called a syrinx).

When surgery is an option, the highly skilled neurosurgeons at Nemours/Alfred I. duPont Hospital for Children are experienced in endoscopically (minimally invasive procedure) performing surgery for Chiari in a procedure called "posterior fossa decompression." Candidates for this surgery have an excellent long-term prognosis, which means that the Chiari malformation repair relieves many symptoms immediately and most symptoms over time.

Posterior Fossa Decompression for Chiari Malformations

Every case is different, however, and the plan your neurosurgeon develops will depend on your child’s specific need, and what’s uncovered during surgery. Generally, the entire posterior fossa decompression procedure can take two to five hours with hospital recovery estimated at four to five days. Most kids are back in school or back to normal activity within two weeks.

What to Expect

While each case is different, posterior fossa decompression includes:

  • craniectomy (removing part of the skull at the bottom that’s causing crowding)
  • laminectomy (removing one or two vertebrae at the top of the spinal cord to provide more room in that area)

At this point, depending on the condition and what’s seen at this time, the neurosurgeon may also:

  • open the dura (the membrane that covers the brain)
  • shrink the cerebellum (using high-frequency electrical current to cauterize or “burn” the cerebral tonsils giving room for the cerebral spinal fluid to flow)
  • patch the dura (using tissue to make the dura wider to reduce pressure on the brain in a procedure called "duraplasty")
  • perform reconstruction (may be necessary to replace missing skull section)

Benefits and Risks

The benefits of any image-guided minimally invasive surgery include better accuracy, faster recovery time, less pain and risk for infection and minimal scarring. The benefit of posterior fossa decompression is reducing or eliminating the symptoms caused by Chiari, which can become life-limiting as a child grows.

Although our neurosurgeons use innovative, image guided intraoperative tools that make these procedures safer with fewer side effects, decompression surgery still carries risk of infection, bleeding and leakage from the patch/duraplasty. Your child’s neurosurgeon will answer all of your questions and help your family make the best decision for your child.

When Additional Surgery Is Necessary

If your child has another medical condition related to the Chiari malformation, such as hydrocephalus or a tethered spinal cord, our neurosurgeons work to combine surgeries whenever possible to reduce the number of procedures your child needs.

Learn More About Neurosurgery at Nemours/Alfred I. duPont Hospital for Children »

What to Expect if Your Child Needs Surgery

If your child needs surgery, you can trust our pediatric surgical team at Nemours/Alfred I. duPont Hospital for Children. Our pediatric surgical specialists (surgeons, anesthesiologists and nurses) understand what kids need, psychologically and physically. Our guidebook provides step-by-step instructions and information about what to expect before, during and right after surgery.

Top 10 Things Kids Need to Know About Surgery

Take your child on a pediatric surgery video tour with Sheridan on her surgery day. This fun, kid-friendly video shows children and teens what to expect, step-by-step, if they need an operation at Nemours/Alfred I. duPont Hospital for Children.

Nonsurgical Treatments for Chiari Malformation Symptoms

Surgery may not be required to repair a Chiari malformation. The neurosurgeons at Nemours/Alfred I. duPont Hospital for Children are most interested in your child’s specific needs and managing Chiari with minimally invasive, non-surgical treatments whenever possible, reserving decompression surgery only when critically necessary.

Convenient Care and Support for the Entire Family

Dealing with a chronic or complex medical condition is difficult for your child and family, but you don’t have to go through it alone. Nemours/Alfred I. duPont Hospital for Children provides an array of support services that begin on the very first day we meet, and continues throughout your journey.

Coping and Support Services

We provide support services that begin on the very first day we meet and continues throughout your journey. Our hospital support services include:

  • Child Life services
  • mental health counseling
  • patient and family education
  • spiritual care
  • social work
  • support groups

Learn More About the Support Services and Amenities at Nemours/Alfred I. duPont Hospital for Children »

Pediatric Chiari Malformations Care Throughout the Delaware Valley

In addition to complete services available at Nemours/Alfred I. duPont Hospital for Children in Wilmington, Del., our Nemours pediatric neurosurgery specialists provide inpatient care at Thomas Jefferson University Hospital for children in Philadelphia.

We also maintain regular outpatient appointment hours at satellite Nemours duPont Pediatrics locations throughout the Delaware Valley:

Electronic Health Record: Keeping Track of Your Child’s Progress

No matter where your child receives care at Nemours, your medical team (including your primary care provider) can access your child’s medical history, test results and visit notes anytime through our award-winning electronic health record system.

You can also view parts of your child's health records, communicate with your Nemours care team, make appointments, request prescription refills and more through our MyNemours online patient portal.

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