Filed under: Children's Health
Craniosynostosis is a birth defect in which one or more of the joints between the bones of your infant's skull close prematurely, before your infant's brain is fully formed. When your baby has craniosynostosis, his or her brain can't grow in its natural shape and the head is misshapen.
Craniosynostosis can affect one or more of the joints in your infant's skull. In some cases, craniosynostosis is associated with an underlying brain abnormality that prevents the brain from growing properly.
Treating craniosynostosis usually means your infant needs surgery to separate the fused bones. If there's no underlying brain abnormality, the surgery allows the brain adequate space to grow and develop.
Your infant's skull has seven bones. Normally, these bones don't fuse until around age 2, giving your baby's brain time to grow. Joints called cranial sutures, made of strong, fibrous tissue, hold these bones together. In the front of your baby's skull, the sutures intersect in the large soft spot (fontanel) on the top of your baby's head. Normally, the sutures remain flexible until the bones fuse.
Craniosynostosis signs in general
Signs of craniosynostosis include:
* A misshapen skull, with the shape depending on which of the cranial sutures are affected
* Abnormal feeling "soft spot" (fontanel) on your baby's skull
* Early disappearance of the fontanel
* Slow or no growth of head as your baby grows
* Development of a raised, hard ridge along affected sutures
* Increased pressure within the skull (intracranial pressure)
The signs of craniosynostosis may not be noticeable at birth, but they will become apparent during the first few months of your baby's life.
Main categories and characteristics
There are two categories of craniosynostosis:
* Primary craniosynostosis. If your baby has primary craniosynostosis, usually one, but sometimes more, of the cranial sutures become rigid, fusing the connecting bones and inhibiting the brain's ability to grow normally.
* Secondary craniosynostosis. With secondary craniosynostosis, which occurs more frequently than the primary type, your infant's brain stops growing, usually due to an underlying hereditary syndrome, allowing the sutures to fuse prematurely. Secondary craniosynostosis is often associated with facial deformities and developmental delays.
Common types and characteristics
The most common types of craniosynostosis are:
* Sagittal synostosis (scaphocephaly). Premature fusion of the suture at the top of the head (sagittal suture) forces the head to grow long and narrow, rather than wide. Scaphocephaly is the most common type of craniosynostosis, and it is more common in boys.
* Coronal synostosis (anterior plagiocephaly). Premature fusion of one of the sutures that run from each ear to the sagittal suture on top of the head may force your baby's forehead to flatten on the affected side. It also may raise the eye socket and cause a deviated nose and slanted skull. This second most common type of craniosynostosis is more common in girls. Untreated, it may lead to vision loss on the affected side (amblyopia).
* Bicoronal synostosis (brachycephaly). When both of the coronal sutures fuse prematurely, your baby may have a flat, elevated forehead and brow.
Rare types and characteristics
Two less common types of synostosis are:
* Metopic synostosis (trigonocephaly). The metopic suture runs from the baby's nose to the sagittal suture. Premature fusion gives the scalp a triangular appearance.
* Lambdoid synostosis (posterior plagiocephaly). This rare form of craniosynostosis involves the lambdoid suture, which runs across the skull near the back of the head. It may cause flattening of the head on the affected side.
Misshapen head may not mean craniosynostosis
A misshapen head doesn't always indicate craniosynostosis. For example, if the back of your baby's head appears flattened, it could be the result of your baby's sleeping on his or her back.
The "Back to Sleep" campaign, co-sponsored by the National Institute of Child Health & Human Development, encourages parents to put healthy babies to sleep on their backs to reduce the risk of sudden infant death syndrome (SIDS). The campaign has resulted in more cases of misshapen heads. In this case, the flattening is a result of positional molding, not craniosynostosis.
When to see a doctor
Contact your doctor if you think your baby's head isn't growing as it should or if it has an unusual shape.
The cause of craniosynostosis is unknown. However, there's a hereditary component to craniosynostosis when it occurs with certain genetic syndromes such as Apert's syndrome and Crouzon syndrome. Besides misshapen heads, infants with these syndromes often have seizures, blindness, developmental delays and mental retardation.
Babies with craniosynostosis, particularly those with an underlying syndrome, may develop increased intracranial pressure. Their skulls don't expand enough to make room for their growing brain.
If untreated, increased intracranial pressure can cause these conditions:
* Brain damage
* Death, in rare instances
In addition, facial deformities that affect the middle of your child's face may cause:
* Upper airway obstructions, compromising your baby's ability to breathe
* Permanent head deformity
Preparing for your appointment
In some cases, your child's doctor may suspect craniosynostosis at a routine well-child visit due to the disappearance of your baby's soft spots or because your baby's head isn't growing as it should.
In other cases, you may make an appointment because you suspect your child has craniosynostosis. As you prepare for this appointment, write down any signs or symptoms you've noticed, such as raised ridges or the absence of soft spots on your baby's head. It's also a good idea to write down any questions you have.
What to expect from your doctor
Your doctor is likely to have questions for you, as well. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:
* When did you first notice the changes in your baby's head?
* How much time does your baby spend on his or her back?
* In what position does your baby sleep?
* Has your baby had any seizures?
* Is your baby's development on schedule?
* Do you have a family history of craniosynostosis or of genetic conditions, such as Apert's syndrome and Crouzon syndrome, that can cause it?
Tests and diagnosis
Your doctor will feel your baby's head for abnormalities such as suture ridges, perform a physical exam and look for facial deformities. In addition, your doctor may order other tests, including:
* Imaging studies. X-rays or a computerized tomography (CT) scan of your baby's skull will show whether any sutures have fused. Fused sutures are identifiable by their absence, because they're invisible once fused, and by the ridging of the suture line.
* Genetic testing. If your doctor suspects your baby's misshapen skull is caused by an underlying hereditary syndrome, genetic testing may help identify the syndrome. Genetic tests usually require a blood sample. Depending on what type of abnormality your doctor is looking for, your baby may be required to give a hair, skin or other tissue sample, such as cells from the inside of the cheek. The sample is then sent to a lab for analysis.
Treatments and drugs
Mild cases of craniosynostosis — those that involve only one suture and no underlying syndrome — may require no treatment. Skull abnormalities may become less obvious as your infant grows and develops hair.
For other infants, surgery, usually during infancy, is the primary treatment for craniosynostosis. However, the type and timing of surgery depend on the type of synostosis and whether there's an underlying syndrome.
The purpose of surgery is to relieve pressure on the brain, create room for the brain to grow normally and improve your child's appearance. A team that includes a specialist in surgery of the head and face (craniofacial surgeon) and a specialist in brain surgery (neurosurgeon) often performs the surgery.
Traditional surgery. The surgeon makes an incision in your infant's scalp and cranial bones, then reshapes the affected portion of the skull. Sometimes plates and screws, often made of material that is absorbed over time, are used to hold the bones in place. Surgery, which is performed during general anesthesia, may take up to seven hours.
After surgery, your infant remains in the hospital for at least three days. Some temporary facial swelling is common after surgery. Complications are rare. Some children may require a second surgery later because the synostosis recurs. Also, children with facial deformities often require future surgeries to reshape their faces.
* Endoscopic surgery. This less invasive form of surgery isn't an option for everyone. But in certain cases, the surgeon may use a lighted tube (endoscope) inserted through one or two small scalp incisions over the affected suture. The surgeon then opens the suture to enable your baby's brain to grow normally. Endoscopic surgery usually takes about an hour, causes less swelling and blood loss, and shortens the hospital stay, often to one day after surgery.
If your baby has an underlying syndrome, your doctor may recommend regular follow-up visits after surgery to monitor head growth and check for increased intracranial pressure.
Coping and support
Having an infant with craniosynostosis can be anxiety-producing and emotionally draining. Talking to families and people who are facing or have faced similar challenges can provide you with information and emotional support.
Ask your doctor about support groups in your community. If a group isn't for you, perhaps your doctor can put you in touch with a family who has dealt with craniosynostosis. Your local health department, public library, telephone book and the Internet also may be good sources for finding support in your area.