Craniosynostosis is a birth defect in which one or more of the seams (sutures) in a baby’s skull close before the baby’s brain has fully formed. Normally, these sutures stay open until babies are about 2 years old and then close into solid bone. Keeping the bones flexible gives the baby’s brain room to grow.

When the joints close too early, the brain pushes against the skull as it continues to grow. This gives the baby’s head a misshapen look. Craniosynostosis can also cause increased pressure in the brain, which can lead to vision loss and learning problems.

There are a few different types of craniosynostosis. The types are based on which suture or sutures are affected and the cause of the problem. About 80 to 90 percent of craniosynostosis cases involve only one suture.

There are two main types of craniosynostosis. Nonsyndromic craniosynostosis is the most common type. Doctors believe it’s caused by a combination of genes and environmental factors. Syndromic craniosynostosis is caused by inherited syndromes, such as Apert syndrome, Crouzon syndrome, and Pfeiffer syndrome.

Craniosynostosis can also be categorized by the affected suture:

Sagittal craniosynostosis

This is the most common type. It affects the sagittal suture, which is at the top of the skull. As the baby’s head grows, it becomes long and narrow.

Coronal craniosynostosis

This type involves the coronal sutures that run from each ear to the top of the baby’s skull. It causes the forehead to appear flat on one side and bulging on the other side. If sutures on both sides of the head are affected (bicoronal craniosynostosis), the baby’s head will be shorter and wider than usual.

Metopic craniosynostosis

This type affects the metopic suture, which runs from the top of the head down the middle of the forehead to the bridge of the nose. Babies with this type will have a triangular head, a ridge running down their forehead, and eyes that are too close together.

Lambdoid craniosynostosis

This rare form involves the lambdoid suture in the back of the head. The baby’s head may look flat, and one side can appear tilted. If both lambdoid sutures are affected (bilambdoid craniosynostosis), the skull will be wider than usual.

The symptoms of craniosynostosis are usually obvious at birth or a few months after. Symptoms include:

  • an unevenly shaped skull
  • an abnormal or missing fontanel (soft spot) on the top of the baby’s head
  • a raised, hard edge along the suture that has closed too early
  • abnormal growth of the baby’s head

Depending on the type of craniosynostosis your baby has, other symptoms can include:

  • headaches
  • wide or narrow eye sockets
  • learning disabilities
  • vision loss

Doctors diagnose craniosynostosis by physical exam. They may sometimes use a computed tomography (CT) scan. This imaging test can show whether any of the sutures in the baby’s skull have fused. Genetic tests and other physical features usually help the doctor identify the syndromes that cause this condition.

About 1 out of every 2,500 babies is born with this condition. In most, the condition happens by chance. But in a smaller number of affected babies, the skull fuses too early due to genetic syndromes. These syndromes include:

  • Apert syndrome
  • Carpenter syndrome
  • Crouzon syndrome
  • Pfeiffer syndrome
  • Saethre-Chotzen syndrome

A small number of babies with mild craniosynostosis won’t need surgical treatment. Rather, they can wear a special helmet to fix the shape of their skull as their brain grows.

Most babies with this condition will need surgery to correct the shape of their head and relieve pressure on their brain. How the surgery is done depends on which sutures are affected and what condition caused the craniosynostosis.

Surgeons can fix the affected sutures with the following procedures.

Endoscopic surgery

Endoscopy works best in infants younger than 3 months, but may be considered for infants as old as 6 months if only one suture is involved.

During this procedure, the surgeon makes 1 or 2 small incisions in the baby’s head. They then insert a thin, lighted tube with a camera on the end to help them remove a small strip of bone over the fused suture.

Endoscopic surgery causes less blood loss and a quicker recovery than with open surgery. After endoscopic surgery, your baby may need to wear a special helmet for up to 12 months to reshape the skull.

Open surgery

Open surgery can be done on infants up to 11 months of age.

In this procedure, the surgeon makes one large cut in the baby’s scalp. They remove bones in the affected area of the skull, reshape them, and put them back. The reshaped bones are held in place with plates and screws that eventually dissolve. Some babies need more than one surgery to correct their head shape.

Babies who have this surgery won’t need to wear a helmet afterward. However, open surgery involves greater blood loss and a longer recovery time than endoscopic surgery.

Surgery can prevent complications from craniosynostosis. If the condition isn’t treated, the baby’s head may be permanently deformed.

As the baby’s brain grows, pressure can build up inside the skull and cause problems such as blindness and slowed mental development.

Surgery can open up the fused suture and help the baby’s brain grow normally again. Most kids who have surgery will have a normally shaped head and won’t experience any cognitive delays or other complications.