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What is craniosynostosis?

Craniosynostosis is a condition in which the fibrous connections, between the bones of the skull, called sutures, grow together (fuse) too early during a child’s development. It most commonly affects only one of the sutures, but it can also occur in more than one. This fusion can cause problems with brain and skull growth. In some cases, it can lead to developmental delays and cognitive problems, especially if more than one suture is involved. Some children with craniosynostosis can also develop high pressure inside the skull, called increased intracranial pressure.

Craniosynostosis is often noticeable at birth, but can also be diagnosed in older children. This condition sometimes runs in families, but most often it occurs randomly.

Types of craniosynostosis

There are four main types of craniosynostosis:

  • Sagittal synostosis is the most common type. Babies with this form of craniosynostosis have closing of the bones that make up the top and sides of the head. This causes the head to look long and narrow.
  • Coronal synostosis causes fused bones along the suture that runs from the ear to the baby’s fontanelle or “soft spot.” If the fusion is on one side only, it’s a unilateral coronal synostosis; if it affects both sides, it’s a bilateral coronal synostosis. Unilateral coronal synostosis can make one side of the forehead look flattened while the other side appears to bulge. Bilateral coronal synostosis can make the head look short and wide.
  • Metopic synostosis involves the fusion of the suture that runs from the "soft spot" on top of the head down the forehead to the top of the nose. Children with this type of craniosynostosis may have a prominent ridge along their foreheads, and their skulls may have a pointed, triangular appearance in front.
  • Lambdoid synostosis is the fusion of the suture in the lower back of the skull. This can cause one side of the back of the head to look flatter than the other side. The ear on that side of the head may also stick out farther than the other ear and be pulled slightly backward. This type of craniosynostosis is extremely rare, and much more commonly flattening in the back of the head is related to a benign condition from the way the baby sleeps.

Meet our patients

a man with crouzon syndrome smiling at the camera

JR's story

JR has received care from Boston Children's Hospital for more than 30 years to treat a rare form of craniosynostosis, befriending a team of providers who have addressed all aspects of his care, including dentistry, neurosurgery, plastic and oral surgery, and psychiatry.


Craniosynostosis | Symptoms & Causes

What are the symptoms of craniosynostosis?

Symptoms of craniosynostosis may vary, depending on which sutures in the skull are involved and how advanced the condition is when it’s diagnosed.

The most common signs of craniosynostosis include:

  • an unusually shaped head or face
  • asymmetrical appearance of the head or skull (one side of the face or top of the head looks different than the other side)
  • an enlarged head or skull
  • a bulging fontanelle (the “soft spot” at the top of a newborn’s skull)
  • bulging eyes

If untreated, craniosynostosis can cause more serious symptoms in some children, including:

  • developmental delays
  • problems with learning, memory, speech, and communication
  • visual disturbance
  • severe nausea and vomiting

Are there other conditions that cause similar symptoms?

Many infant skull shape irregularities are actually due to a condition called plagiocephaly, which is caused by a baby’s position during sleep. Plagiocephaly is a common disorder and does not require surgery. Your clinician can help diagnose which condition your child has.

What are the causes of craniosynostosis?

Experts often cannot identify what causes craniosynostosis. In most cases, it appears to happen randomly. Increasingly, a genetic cause is identified.

Craniosynostosis | Diagnosis & Treatments

How is craniosynostosis diagnosed?

Many children with craniosynostosis have visible symptoms — such as a misshapen or asymmetrical head — at birth. Other times, a child’s craniosynostosis is diagnosed during a routine physical examination.

Your clinician may diagnose craniosynostosis based on his or her symptoms along with a detailed patient history and a full exam that includes a careful assessment of the shape of the skull.

In rare cases, craniosynostosis may be diagnosed before birth by a prenatal ultrasound or magnetic resonance imaging (MRI).

What tests will my child need?

To diagnose craniosynostosis, often no additional tests are needed other than assessment by an expert. Your child’s clinician may also use one or more of the following tests:

  • Computed tomography (CT) scans: CT scans use x-ray equipment and powerful computers to create detailed images of the head and brain, including skull sutures and bones. This is the main test used for craniosynostosis.
  • Magnetic resonance imaging (MRI): MRIs uses a combination of electromagnets and radio waves to take detailed images of the brain.

What are the treatment options for craniosynostosis?

Most, but not all, children with craniosynostosis need surgery to relieve pressure on the brain and correct the shape of the head. In some mild cases, observation might be the best treatment alternative.

Surgery for craniosynostosis often works best in children under age 1, since the bones are still soft and pliable, making them easier to move. Older babies and children can also have surgery, but it may be more complex. In rare cases, the surgery may need to be repeated over time, as the child grows.

The surgeon may use:

  • minimally invasive surgery to release the sutures that are fused
  • reconstructive surgery to reposition the skull bones to allow for normal growth and development

How we care for craniosynostosis

At Boston Children’s Hospital, our clinicians in Neurosurgery and Plastic Surgery have extensive experience diagnosing and treating craniosynostosis in infants and children of all ages — using minimally invasive procedures whenever possible.

Frequently asked questions

Will my child be OK?

The severity of craniosynostosis can vary widely, depending on the type of craniosynostosis your child has and how many sutures are affected. The good news is that with early detection and prompt treatment, most children don’t have any significant long-term problems.

How common is craniosynostosis?

This condition affects about one in every 2,500 children.

At what age is craniosynostosis usually diagnosed?

Craniosynostosis is almost always noticeable at birth, although mild conditions may not be found until later in infancy or childhood. Physicians can sometimes detect craniosynostosis during pregnancy, but this is not common.

Will my child need surgery?

Craniosynostosis is often a progressive condition. This means that if it is not treated, the symptoms may get worse over time. As a result, most children with craniosynostosis need surgery to prevent problems with brain and skull growth and to correct skull deformities. Your clinician can help you decide if surgery is the right treatment for your child.

Craniosynostosis | Programs & Services