Craniosynostosis is a condition that occurs in infancy, in which the sutures between the bones of the skull close before the skull has had a chance to complete its growth. This premature hardening may interfere with the formation of the bones of the skull and face. At Columbia, our pediatric neurosurgeons are experts in diagnosing and taking care of children who have craniosynostosis.
Though not always necessary, there is surgical treatment to correct craniosynostosis. Craniosynostosis surgery allows the bones’ shapes to improve. It is also occasionally required to reduce pressure buildup in the skull. In some cases, the surgery may facilitate neurological development.
Craniosynostosis is sometimes called “craniostenosis” or “synostosis.” Craniosynostosis may be simple (one suture fused) or compound (multiple sutures fused).
The plates of the head usually grow at the sutures as the brain expands, permitting the rapid head growth normal for infants and young children. At birth, an infant’s head is typically only about 25 percent of its eventual adult size. By 12 months, it has reached 75 percent of its adult size, with the fastest growth occurring in the first 8 months. After that, the rate of growth slows: At 3 years old, the head is 80 percent, and at 7 years old 90 percent, of its adult size.
Usually, the skull plates gradually harden from their centers outward. Eventually they knit together at the sutures and form a single skull bone. When craniosynostosis interrupts this process during the rapid growth of infancy, changes in an infant’s head and face shape can result.
Physicians often recognize this condition when an infant’s face (especially eyes and nose) appears asymmetrical, and/or the skull takes on one of the shapes described below. Another sign is a small or absent fontanelle. In some cases, synostosis can cause elevated intracranial pressure that can prevent the brain from developing normally. This is especially true when more than one suture is fused.
Instances of simple craniosynostosis are categorized according to the changes they cause in bone shape. Compound craniosynostosis results in more complex changes in skull shape.
- The most common type of craniosynostosis is scaphocephaly. This premature fusion of the sagittal suture causes the skull to be long from front to back and narrow from ear to ear. This suture runs front to back, down the middle of the top of the head.
- Trigonocephaly may affect bone growth in such a way that a ridge runs down the infant’s forehead. Sometimes the forehead looks quite pointed, like a triangle, and the infant may have hypotelorism. This type of craniosynostosis comes from a fusion of the metopic suture, which runs from the fontanelle down the middle of the forehead, toward the nose.
- Plagiocephaly is a condition in which the skull shape is atypical in several ways. By far the most common type of plagiocephaly is not due to craniosynostosis at all. It is the very common, readily treatable “deformational plagiocephaly” or “positional plagiocephaly.” It results from repeated pressure to the same area of the head, and it frequently occurs when an infant sleeps always in the same position. As always, speak to your child’s healthcare provider if you have any concerns. Doctors can distinguish positional plagiocephaly—which does not require surgery to treat—from plagiocephaly due to craniosynostosis, which most often does require surgery.
Craniosynostosis may cause plagiocephaly when either the left or right coronal suture or one of the lamboid sutures fuses early. An infant for whom this takes place may have a forehead and brow that are flatter than usual on one side, with the forehead more prominent on the opposite side. The eye on the affected side may also have a different shape, and the ear position may be asymmetric. There may also be flattening at the back of the head.
The diagnosis is made after a thorough physical examination. Diagnostic testing is occasionally needed in unusual cases.
Craniosynostosis may be observable at birth (though it is important to note that a newborn’s skull is often temporarily molded by its passage through the birth canal). Craniosynostosis may be observed during a physical examination later in infancy.
During the examination, the doctor will obtain a complete prenatal and birth history of the child. A measurement of the circumference of the child’s head is plotted on a graph to identify normal and abnormal ranges. The doctor may ask if there is a family history of craniosynostosis or other head or face abnormalities.
The doctor may also ask about developmental milestones, since craniosynostosis can sometimes be associated with developmental delays. Developmental delays may require further medical follow-up for underlying problems. At Columbia, specialists in various areas of pediatrics are always available to help track down and address any such problems.
Diagnostic tests that may be performed to confirm the diagnosis of craniosynostosis include X-rays and CT scans. X-rays use invisible electromagnetic energy beams to produce images of internal tissues and bones. CT scans (also known as CAT scans, or computed tomography scans) use a combination of X-rays and a computer to produce horizontal, or axial, images (often called slices). Three dimensional reconstructions are often made from CT scans to show the bone plates and sutures. A CT scan shows detailed images of any part of the body, including bones, muscles and organs. CT scans are more detailed than X-rays.
Craniosynostosis is sometimes classified according to whether it is primary or secondary. Research is ongoing about the cause of primary craniosynostosis. The most generally accepted hypothesis is that primary craniosynostosis is a result of a problem with ossification, or conversion of tissue to bone, at one of the sutures. Another hypothesis under investigation is that adherence of the dura to a bone plate restricts the bone’s movement and promotes early suture closure. No risk factors have been identified; primary craniosynostosis seems to arise at random. It can generally be treated surgically.
Secondary craniosynostosis arises as a result of a separate problem, such as microcephaly, rickets, or renal osteodystrophy, among others. In secondary craniosynostosis, the underlying problem must also be addressed when possible.
Craniosynostosis most often occurs sporadically. However, it is also a possible symptom of many different genetic syndromes, particularly when more than one suture is affected. The most common of these are Apert syndrome and Crouzon syndrome, but many syndromes are possible. Therefore, it may be important for a child and his or her family members to be examined for signs of a syndromic cause of craniosynostosis—such as limb defects, ear abnormalities, or cardiovascular malformations. Then treatment can be tailored toward managing or even correcting other symptoms of the syndrome.
When craniosynostosis is confirmed, treatment is required and the recommended treatment is craniofacial surgery.
If a skull deformity exists but craniosynostosis is not present, treatment may not be required in all cases.
For example, treatment may not be required if the deformation is quite slight. With very slight deformations, complications are rare and the appearance will become less pronounced as the child grows. A young child’s head is very large compared with the body, and it has very little hair. As the head and body come into more adult proportion and the scalp is covered with hair, a slight deformation will not be as apparent.
In cases of secondary craniosynostosis, an underlying condition may not be responsive to surgery. In these instances, other doctors can be more helpful than the surgical team.
When craniofacial surgery is recommended, a team of specialists may be involved. Depending on the type of surgery recommended, the procedure may be performed as early as a couple months of age or around six to nine months of age. The two general approaches to surgery are cranial vault reconstruction and suturectomy.
- Cranial vault reconstruction is a traditional open surgery that is the classic option for craniosynostosis. This is a longer and more invasive procedure than suturectomy, but it immediately corrects the skull shape. In this surgery, doctors remove the skull plates, re-shape them, and replace them. This surgery typically lasts several hours and is usually performed after the age of 6 months. Blood transfusions are always necessary after this surgery.
- Suturectomy is a minimally invasive procedure, performed with an endoscope through one-inch incisions. In this procedure, surgeons perform a more limited removal—of just the fused suture. Once the bones are not “locked” together at that suture, the skull is free to expand normally. The child is placed in a custom-made helmet to aid in the re-contouring of the skull as it grows. This surgery lasts about one hour. It is most often performed in the first four months of life, while the skull is growing rapidly. Blood transfusions are much less common with this procedure.
Before surgery, your child’s doctor will explain the different options for surgery and make a recommendation.
Following the operation, it is common for the child to have a turban-like dressing around his or her head. The face and eyelids may be swollen. The child is typically transferred to the pediatric intensive care unit after the operation for close monitoring.
Recent research has shown that children may benefit from craniosynostosis surgery in more ways than previously thought.
In the past, surgery was recommended for two reasons: Treatment reduced the physical deformity of the child’s head and face and also prevented the less common but serious complication of elevated intracranial pressure. However, we now know that some kinds of craniosynostosis can also affect a child’s development. There is some evidence that surgery may help improve development, and that early surgery may be more helpful than later surgery in that regard.
Studies have followed the neurological development of children who have been surgically treated for simple craniosynostosis that is not associated with a genetic syndrome. Many of the children had delays in their motor development during early childhood. However, by the elementary years, more than half the children had no discernable learning problems. Children who had scaphocephaly, the most common form of craniosynostosis, were least likely to have learning problems.
In secondary craniosynostosis, or synostosis associated with a genetic syndrome, the child’s development is also affected by the underlying cause or the genetic syndrome. So these research findings may or may not be significant in your family. Your child’s health care team will discuss your particular situation with you.
Children who have been treated for craniosynostosis should receive frequent medical and neurodevelopmental follow-up. Medical follow-up will ensure that the child’s skull, facial bones and brain continue to develop normally. Neurodevelopmental evaluation can help determine whether therapy for learning or motor skills might be important. These interventions can have dramatic effects for children who may be at risk for delays. Your child’s medical team will help you navigate these follow-up recommendations.