What is craniosynostosis?
The normal skull consists of several plates of bone that are separated by sutures. The sutures (fibrous joints) are found between the bony plates in the head. As the infant grows and develops, the sutures close and the bones fuse together, forming a solid piece of bone, called the skull.
Craniosynostosis is a condition in which the sutures close too early, causing problems with normal brain and skull growth. Premature closure of the sutures may also cause the pressure inside of the head to increase and the skull or facial bones to change from a normal, symmetrical appearance.
What causes craniosynostosis?
Craniosynostosis occurs in one out of 2,000 live births and affects males slightly more often than females.
Craniosynostosis is most often sporadic (occurs by chance). In some families, craniosynostosis is inherited in one of two ways:
• Autosomal recessive. Autosomal recessive means that two copies of the gene are necessary to express the condition, one inherited from each parent, who are obligate carriers. Carrier parents have a one in four, or 25 percent, chance with each pregnancy, to have a child with craniosynostosis. Males and females are equally affected.
• Autosomal dominant. Autosomal dominant means that one gene is necessary to express the condition, and the gene is passed from parent to child with a 50/50 risk for each pregnancy. Males and females are equally affected.
Craniosynostosis is a feature of many different genetic syndromes that have a variety of inheritance patterns and chances for reoccurrence, depending on the specific syndrome present. It is important for the child as well as family members to be examined carefully for signs of a syndromic cause (inherited genetic disorder) of craniosynostosis such as limb defects, ear abnormalities, or cardiovascular malformations.
What are the different types of craniosynostosis?
There are numerous types of craniosynostosis. Different names are given to the various types, depending on which suture, or sutures, are involved, including the following:
• Plagiocephaly. Plagiocephaly involves fusion of either the right or left side of the coronal suture thatruns from ear to ear. This is called coronal synostosis and it causes the normal forehead and the brow to stop growing. Therefore, it produces a flattening of the forehead and the brow on the affected side, with the forehead tending to be excessively prominent on the opposite side. The eye on the affected side may also have a different shape. There may also be flattening of the back area (occipital). Unilateral lambdoidal suture synostosis may cause plagiocephaly, as well.
Deformational (or positional) plagiocephaly refers to the misshapen (asymmetrical) head from repeated pressure to the same area of the head. This is not a true synostosis. It can result when the part of the skull (occipital bone) that is dependent (in one position) flattens out due to pressure, as when sleeping on that part of the skull.
The number of infants with deformational plagiocephaly has risen over the past several years. This increase may be the result of the “Back to Sleep” campaign promoted by the American Academy of Pediatrics (AAP) to help prevent sudden infant death syndrome (SIDS), but other factors can cause this type of plagiocephaly. Specific treatment will be determined by your child’s health care provider based on the severity. Deformational plagiocephaly is treated by altering the child’s usual position of sleep or using a specially molded helmet which will reshape the head over time. The AAP recommends supervised tummy time if an infant is awake to help prevent positional plagiocephaly.
• Trigonocephaly. Trigonocephaly is a fusion of the metopic (forehead) suture. This suture runs from the top of the head down the middle of the forehead, toward the nose. Early closure of this suture may result in a prominent ridge running down the forehead. Sometimes, the forehead looks quite pointed, like a triangle, with closely placed eyes (hypotelorism).
• Scaphocephaly. Scaphocephaly is an early closure of fusion of the sagittal suture. This is the most common type of synostosis. This suture runs front to back, down the middle of the top of the head. This fusion causes a long, narrow skull. The skull is long from front to back and narrow from ear to ear.
What are the symptoms of craniosynostosis?
In infants with this condition, changes in the shape of the head and face may be noticeable and are generally the first and only symptom. The appearance of the child’s face may not be the same when compared to the other side. Another sign is small or absent fontanelle. Less commonly, synostosis can cause increased pressure within the skull. This is especially true when multiple cranial sutures are fused prematurely. In infants with this condition, changes in the shape of the head and face may be noticeable and are generally the first and only symptom. The appearance of the child’s face may not be the same when compared to the other side. Another sign is small or absent fontanelle. Less commonly, synostosis can cause increased pressure within the skull. This is especially true when multiple cranial sutures are fused prematurely. Symptoms of increased pressure in the skull include:
• Full or bulging fontanelle (soft spot located on the top of the head)
• Sleepiness (or less alert than usual)
• Scalp veins may be very noticeable
• Increased irritability
• High-pitched cry
• Poor feeding
• Projectile vomiting
• Increasing head circumference
• Bulging eyes and an inability of the child to look upward with the head facing forward
• Developmental delays
The symptoms of craniosynostosis may resemble other conditions or medical problems. Always consult your child’s doctor for a diagnosis.
How is craniosynostosis diagnosed?
Craniosynostosis may be congenital (present at birth) or may be observed later, during a physical examination. The diagnosis is made after a thorough physical examination and after diagnostic testing. During the examination, your child’s doctor will obtain a complete prenatal and birth history of your child. He or she may ask if there is a family history of craniosynostosis or other head or face abnormalities. Your child’s doctor may also ask about developmental milestones since craniosynostosis can be associated with other developmental delay. Developmental delays may require further medical follow-up for underlying problems.
During the examination, a measurement of the circumference of your child’s head is taken and plotted on a graph to identify normal and abnormal ranges.
Diagnostic tests that may be performed to confirm the diagnosis of craniosynostosis include:
• X-rays of the head. A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues and bones of the head onto film.
• Computed tomography scan (also called a CT or CAT scan) of the head. A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the head. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
Management of craniosynostosis
Specific treatment for craniosynostosis will be determined by your child’s doctor based on:
• Your child’s age, overall health, and medical history
• 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 and correct the deformities of the face and skull bones. Less commonly, surgery is needed to decrease pressure within the skull.
The optimal time to perform surgery is before the child is 1 year of age since the bones are still very soft, have not fused at other sutures, and are easy to work with. Surgery may be necessary at a much earlier age depending on the severity of the condition. Because blood loss can be an issue in this type of surgery, surgery is often delayed in the very young child to allow some growth and development and a greater blood volume. Most procedures are done between 3 and 8 months of age.
Before surgery, your child’s doctor will explain the operation and may review “before and after” photographs of children who may have had a similar type of surgery.
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 after this type of surgery. The child is typically transferred to the intensive care unit (ICU) after the operation for close monitoring.
Problems after surgery may occur suddenly or over a period of time. The child may experience any or all of the following complications:
• Redness and swelling along the incision areas
• Decreased alertness
These complications require prompt evaluation by your child’s surgeon. The health care 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.