Craniosynostosis

What is craniosynostosis?

A baby’s skull is made up of multiple bone plates that are separated by small gaps called sutures. The sutures are essentially joints that allow the skull to expand as an infant grows. Initially the gaps allow the skull to be flexible as a baby comes through the birth canal. In the first few years of life the baby’s brain is expanding and pushing the bones apart at the sutures to allow for the growth. Eventually the sutures will become more fixed as the growth slows down and will form the solid adult skull.

Craniosynostosis occurs when the sutures either do not develop properly or close too early. This limits the growth of the skull and the normal brain. In most cases this causes the skull to grow in an abnormal way to allow for growth of the brain. Sometimes this causes increased pressure in the brain which can lead to developmental issues, headaches, or other symptoms. Some forms of craniosynostosis also affect the growth of the face and facial bones as well as the eye sockets or orbits.

Most types of craniosynostosis are evident at birth . Many times the abnormal head shape can be mistaken for other more common causes of head shape changes at birth. In particular, extended labor, positioning in the birth canal or birth difficulties can cause head shape abnormalities that can confuse the diagnosis. Most of these issues will resolve in the first month of life and the head shape will become more normal. Craniosynostosis will worsen over time.

What causes craniosynostosis?

In some cases craniosynostosis can be genetic and passed down through the parents to the children. In most cases craniosynostosis is random and a specific cause is unknown. There is nothing a mother can do to prevent an infant from developing craniosynostosis and there is nothing that a parent did to cause craniosynostosis.

Craniosynostosis is present in one out of 2000 live births. There are also many different genetic syndromes that are associated with craniosynostosis. Some of these syndromes can have additional birth defects such as limb or finger defects, hydrocephalus, brain anomalies, or other facial deformities. It is important for children and their families to be evaluated if a genetic association is suspected. Common syndromes include Apert’s and Crouzon’s but there are many more.

What are the different types of Craniosynostosis?

The different forms of craniosynostosis are determined by the suture that is involved. The most common forms of craniosynostosis involve the four major sutures. These are the sagittal, coronal, metopic and lambdoid sutures. Closure of the sagittal suture is the most common form of synostosis and the lambdoid suture is the least common to be involved.

Sagittal Synostosis (Scaphocephaly or Dolicocephaly)

Scaphocephaly or dolicocephaly are terms used to describe the head shape that results from closure of the sagittal suture. This is the most common and simplest form of craniosynostosis.  The sagittal suture runs from the front to the back of the head. When this suture is closed it restricts the growth of the skull out to the sides and causes a very long and narrow shaped head. There is often a ridge that is felt along the middle of the skull where the suture normally runs. Most of the time the other sutures are open and these will compensate for the limited growth. This causes the bones in the front and the back of the skull to grow more than usual resulting in a bulging forehead and back of the head (occipital). This form of craniosynostosis is also the easiest to repair.

Coronal Synostosis (Anterior Plagiocephaly)

Plagiocephaly means flatness of the skull and flattening in the front of the skull or forehead can be caused by closure of one or both of the coronal sutures. This is called coronal synostosis. Typically this affects the growth of the forehead on one side as well as flattening of the eyebrow on the same side. Sometimes the eye on that side will also appear to be “popping out”. The forehead on the opposite side will tend to stick out or protrude as is often mistaken as the “abnormal” side.

Bilateral coronal synostosis restricts the growth of the forehead on both sides resulting in a flat and wide or flat and tall forehead and flat eyebrows on both sides.

Metopic Synostosis (Trigonocephaly)

Trigonocephaly means triangular shaped head and reflects the changes that occur when the metopic suture is closed. The metopic suture runs down the middle of the forehead from the soft spot to the top of the nose. This makes it difficult for the forehead to grow and produces a very narrow and pointed forehead. To compensate for this the back of the head or parietal bones tend to grow out very wide at the back of the head. The eyes tend to be sitting very close to each other called hypotelorism. There is usually a ridge running down the middle of the forehead. A metopic ridge can be present, however, even when there is no evidence of a triangular shaped head. Typically a simple metopic ridge will resolve on its own without intervention.

Lambdoid Synostosis (Posterior Plagiocephaly)

Flattening of the back of the head is most commonly caused by positioning especially now that infants sleep on their backs called “Positional plagiocephaly”. Rarely closure of the lambdoid suture is actually the cause of the flattening of the back of the head. The “positional” form of flattening is not related to a skull growth problem and does not require any surgical intervention. The problem in these cases is just related to how the infant is positioned and can be corrected with repositioning in most cases. For further information about “positional plagiocephaly” or “flat head syndrome” you can go to our page on positional plagiocephaly.

In cases where the lambdoid suture is truly closed there is a very characteristic head shape with a flat back of the head and a large bulge on the opposite side of the head where the skull is trying to grow in other directions to allow the brain to expand as the baby develops. In most cases the difference between true craniosynostosis and “positional plagiocephaly” can be determined by clinical exam but CT is sometimes needed if it is difficult to tell by exam alone.

How do you know if an infant has craniosynostosis?

True craniosynostosis is typically present at birth but is often mistaken for molding of the head or changes that can occur with childbirth or prolonged labor. It is not uncommon for infants born with craniosynostosis to have a difficult delivery due to difficulties passing through the birth canal. With coronal and metopic synostosis changes in the face may cause the face to be different on one side compared to the other.

Typically there are not any specific symptoms and children are typically developmentally and neurologically normal. Most of the features that are seen at birth are related to the suture involved and the severity. The soft spot can be small or large and the head size does not usually correlate with synostosis. Ridging of the sutures can be seen as well as bulging of the eyes. Occasionally, irritability or delays can be seen but typically only when more than one suture is involved.

How is the diagnosis of craniosynostosis made?

Most of the time craniosynostosis is congenital or present at birth and the diagnosis can be made by examining the child and with imaging of the head. Sometimes the abnormality is noted at birth or in the neonatal unit. Many times the diagnosis is made later during your baby’s well visit checks with the pediatrician or other physician’s. A thorough history of the birth and development is important in determining the diagnosis. Occasionally, craniosynostosis is seen with other abnormalities or a syndrome and it is important for your physician to perform a thorough exam to look for other abnormalities. It is also important to know if there is a family history of craniosynostosis.

If your pediatrician is worried about craniosynostosis, your child will be referred to a Pediatric Neurosurgeon or craniofacial clinic for evaluation. Most of the time, the diagnosis can be made clinically by looking at your child’s head shape and feeling the suture lines. It is not necessary to have any imaging done prior to your visit with the Pediatric Neurosurgeon as most of the time special images will need to be obtained and we try to avoid repeating imaging studies.

MRI is not typically used as it does not show the bones well enough to see if there is true craniosynsotosis. Plain x-rays are also not very useful because they are not very accurate for this type of problem.

In most cases a CT scan or CAT scan will be performed with a 3-D CT. This involves a combination of X-rays and computer technology to produce cross sectional slices of the head which are then used to create a three dimensional model of the skull. This is very helpful in confirming the diagnosis and essential to make sure that there are not more than one suture involved. It is also very easy to see the closed suture which is helpful for family members trying to understand the diagnosis. The CT scan is quick and does not require a child to be sedated in most cases. The radiation dose is small when performed on a good scanner. Many times the scan can be done on the day of your visit if scheduling and insurance permit.

How is craniosynostosis treated?

Because true craniosynostosis restricts the growth of the skull it can not be corrected with time, positioning or a helmet. The treatment depends on the child’s age, overall health, and medical history but typically requires surgery at some point. The timing and extent of surgery depends on the:

• Extent of the craniosynostosis
• Type of craniosynostosis (which sutures are involved)
• Your child’s tolerance for specific medications, procedures, or therapies
• Expectations for the course of the craniosynostosis
• Your opinion or preference

Surgery is typically the recommended treatment. The goal of treatment is to reduce the pressure in the head, correct the deformities of the face and skull bones, and allow for further growth and development.

The optimal time to perform surgery depends on the suture involved and the severity of the deformity. It is generally easier to perform surgery at a younger age since the bones are still very soft and easy to work with. Surgery may be necessary at a much earlier age depending upon the severity of the condition.

In the case of sagittal synostosis, surgery can be done as early as 2-3 months of age and in other types of craniosynostosis we generally recommend surgery between 6-7 months.

Before surgery, your child’s physician will explain the operation and may review “before and after” photographs of children who may have had a similar type of surgery. Depending on the type of surgery needed, a more extensive craniofacial team will be used including Plastics or a Craniofacial surgeon in addition to a Pediatric Neurosurgeon. Some surgeries only involve Pediatric Neurosurgery.

Following the operation, the face and eyelids may be swollen. The child is typically transferred to the intensive care unit (ICU) after the operation for close monitoring. Initially the blood levels are closely watched in the ICU, The child is generally awake and eating within a few hours of surgery. There is typically a small drain that is placed under the skin to help with swelling.

Usually, after an initial monitoring period in the ICU typically about 24 hours, the child is transferred to a regular hospital room. Once the child is eating well and back to normal behavior, the child is ready to go home. Typically the total hospital stay is around 2-3 days. By the time your child is released they are typically back to normal activity and require only Tylenol or a mild narcotic for pain.

Problems after surgery are rare but may occur suddenly or over a period of time. Problems can include: fever, swelling, poor feeding, seizures, wound healing problems or infection.

These complications require prompt evaluation by your child’s surgeon. The healthcare team educates the family after surgery on how to best care for their child at home, and outlines specific problems that require immediate medical attention. In general, patients are allowed to return to normal activity and bathing and do not have any restrictions. Typically a helmet is not required.

Life-long considerations for a child with craniosynostosis

The key to treating craniosynostosis is early detection and treatment. Some forms of craniosynostosis can affect the brain and development of a child. The degree of the problem is dependent on the severity of the craniosynostosis, the number of sutures that are fused, and the presence of brain or other organ system problems that could affect the child. Most children go on to live healthy normal lives.

Genetic counseling may be recommended by the physician to evaluate the parents of the child for any hereditary disorders that may tend to run in families.

A child with craniosynostosis requires frequent medical evaluations to ensure that the skull, facial bones, and brain are developing normally. The medical team works with the child’s family to provide education and guidance to improve the health and well being of the child.

After surgical correction, it is important to follow with your physician to make sure that the bones heal correctly. Rarely, additional procedures may need to be performed if additional correction is needed.

Are you concerned about craniosynostosis?

Primary evaluation and treatment of craniosynostosis is provided at the Pediatric Neuroscience Center by Dr. Renatta Osterdock, Pediatric Neurosurgery. If you are concerned that your child may have craniosynostosis, please call the Pediatric Neuroscience Center at 303-832-2449 for an appointment to be evaluated. It is not necessary to have any x-rays or CT scans done prior to your appointment. We will schedule the needed tests at the appropriate time for your child.