The bones of the fetal skull are connected by fibrous joints, called “sutures.” In normal development, these sutures remain open through infancy—first to allow passage through the birth canal and later so the brain has space to develop. Craniosynostosis occurs when one or more sutures close (or “fuse”) prematurely. When this happens the skull cannot grow into its natural shape, resulting in a misshapen skull and/or facial bones and, sometimes, increased pressure on the brain. In some cases, craniosynostosis is associated with an underlying syndrome.
How common is it?
Craniosynostosis is seen in approximately one in 2,000 births. It is not typically detected during pregnancy and if so, usually not until the third trimester.
How is it diagnosed?
Craniosynostosis is most often diagnosed after birth when the infant’s head shape is abnormal; however, it can occasionally be detected prenatally through ultrasound. A level II ultrasound may be performed to determine if there are associated anomalies, including those of the hands, feet and heart; and amniocentesis may be performed to look for chromosomal anomalies.
What can happen before birth?
Most often only one suture fuses, but in rare instances multiple sutures may fuse, resulting in significantly abnormal head shapes and increased pressure inside the skull. The most common single suture synostoses are:
- Anterior plagiocephaly or coronal synostosis: the fusion of either the right or left side of the suture that extends ear to ear. This can result in a flattening of the forehead and brow on one side, asymmetries of the orbit (eye socket), and deviation of the nose.
- Trigonocephaly or metopic synostosis:the fusion of the suture that extends from the top of the head, through the middle of the forehead toward the nose. This can result in a triangular forehead with closely placed eyes.
- Scaphocephaly or sagittal suture synostosis:the fusion of the suture that extends through the middle of the top of the head, running front to back. The most common type of fusion, scaphocephaly can result in a skull that is long from front to back and narrow from ear to ear. The back of the head is often narrow and pointed.
What can be done before birth?
Craniosynostosis is best treated after birth because fetal intervention poses too many risks for you and your unborn baby, without any known benefits.
What are my delivery options?
Unless there are signs that the fetus is in trouble, pre-term delivery or Cesarean section is not necessary. Cesarean section may be necessary for obstetrical reasons, however.
What will happen at birth?
If your baby hasn’t been diagnosed prenatally with craniosynostosis and is born with an abnormally shaped head, he or she will undergo clinical evaluation. If the head shape is suggestive of craniosynostosis, we will perform computerized tomography of the head to assess the bones. Head shape abnormalities are most often related to positioning.
If your baby is found to have craniosynostosis, he or she will receive care from specialists in many areas including: plastic surgery, neurosurgery, genetics and ophthalmology. Craniosynostosis is most often treated with surgery between five months and one year of age, depending on the type of synostosis. In this operation the fused bones are released, and the head shape is remodeled to a more normal shape with additional room for the brain to grow.
Your baby will recover in the pediatric intensive care unit typically overnight, followed by two to four days in the hospital.
What is the long-term outcome?
The long-term outcome depends on the type and severity of the craniosynostosis, and whether it is part of a larger syndrome. Typically children require only one operation and do very well, and are usually indistinguishable from their peers. Your child will be followed annually until skeletal maturity to monitor progress.