What is craniosynostosis?

A baby's skull has 5 thin bony plates that are held together by a fiber-like material called sutures. The sutures allow a baby's skull to expand as the brain grows. Over time, the sutures harden and close (fuse) the skull bones together. When a fetus or baby has craniosynostosis (craniostenosis), one or more of these sutures close too soon. This causes the baby's head to become abnormally shaped.

The effects of craniosynostosis on a fetus or baby depend in part on how many of the skull sutures are affected.

• Most often, craniosynostosis affects only one suture. More than half of all cases involve the sagittal suture. The sagittal suture runs across the top of a baby's head from front to back.1 The baby's brain usually develops normally in these cases, but the head becomes abnormally shaped. The skull may become long and narrow or very flat and broad in front or back or on the sides. This depends on which suture closes prematurely.
• Craniosynostosis can develop along more than one suture. When more than one suture closes prematurely, the baby's brain may not be able to grow at its expected rate. In addition, pressure may build up around the brain, causing brain damage, seizures, blindness, and developmental delays. Over time, this can lead to permanent disabilities if the condition is not treated. A baby with more than one suture affected by this condition may have facial defects, such as a misshapen nose or jaw.

What causes craniosynostosis?

Doctors do not fully understand what causes craniosynostosis. Up to 20% of babies with craniosynostosis have inherited a genetic trait from one or both parents that results in the condition.2

Some cases of craniosynostosis may be related to fetal growth or position or other conditions during pregnancy. Fetuses that lie in a breech position while in the womb, are carried by mothers who smoke or who live at a high altitude during pregnancy, or are twins may have an increased risk of developing craniosynostosis.

Craniosynostosis is one of the most common physical deformities of a fetus or newborn, occurring in about 1 in every 2,000 to 2,500 births.3

What are the symptoms?

The most common sign of craniosynostosis is an irregularly shaped head at birth or within the first few months of life. This may be the only sign of the condition.

Although most cases of craniosynostosis are diagnosed based on an irregularly shaped head, some babies become ill. This can happen when more than one suture closes too early. This limits the brain's ability to grow and causes pressure on the brain. As pressure builds on the brain, your baby may:

• Vomit.
• Become sluggish, sleep more, and play less.
• Become irritable because of head pain.
• Develop swollen eyes or problems moving the eyes or following objects.
• Have problems hearing.
• Breathe noisily or have periods of not breathing (apnea).

In extremely severe cases, a baby may have seizures, blindness, and developmental delays and disabilities.

How is craniosynostosis diagnosed?

You or your doctor may notice that your baby has an irregular head shape at birth or shortly afterward. Or, your doctor may identify it later at a regular well child checkup. Just because your baby has an irregularly shaped head doesn't mean he or she has craniosynostosis. A misshapen head may be caused by how your baby was positioned in your womb, the birth process, and/or sleep position during infancy. A misshapen head caused by any of these factors usually gets better its own or is easily treated.

Your baby's doctor will measure the baby's head at birth and during well child exams. He or she will also feel and examine the lines between the bony plates of the baby's skull (sutures) and the soft spots (fontanelles).

If your baby's skull is severely misshapen at birth or slight irregularities do not improve over time, your baby's doctor may order a skull X-ray, CT scan, or MRl to help determine whether craniosynostosis is the cause. In addition, your baby's doctor may ask you questions about your medical history to determine whether your baby may have inherited a genetic form of craniosynostosis.

How is it treated?

Surgery is the only treatment for craniosynostosis. It works best when it is performed when your baby is as young as possible.