Sagittal craniosynostosis is a congenital defect that causes the sagittal suture on the very top of the skull to close earlier than normal. As a result, the head grows long and narrow rather than wide, and the affected child will likely have a broad forehead. Newborns’ skulls consist of several sutures or anatomical lines where the bony plates will eventually fuse together. Sagittal is the most common type of craniosynostosis, and surgery is the most common treatment.
When a child is born, her skull is soft, with gaps between plates of bone. These gaps are called cranial sutures. This allows the skull to grow with the brain. As the brain reaches its full size, these sutures close, fusing the bony plates together. The soft spot on top of a newborn’s head is a large gap between such plates that will eventually close.
Craniosynostosis is a condition that occurs when one or more of the sutures between bony plates closes early. This affects the growth of the skull, the brain, and the shape of the head. Skull bones that are meant to continue expanding with the growth of the brain are fused together too soon, resulting in a visually apparent head deformity.
There are several types of craniosynostosis characterized by the suture or sutures involved. The most common type is sagittal, affecting more boys than girls, while the frontal and metopic types are rarer. The coronal suture that runs between ears over the top of the skull closes prematurely in cases of frontal plagiocephaly. Metopic synostosis is characterized by the closure of the metopic suture close to the forehead. The suture affected determines how the head will grow.
Sagittal craniosynostosis occurs when the sagittal suture that runs long the very top of a newborn’s skull closes prematurely. As a result, the baby’s skull grows in a conical shape that is longer and narrower than it is wide. Overall, craniosynostosis occurs in approximately one in 2,000 live births.
The most obvious symptom of sagittal craniosynostosis is the abnormal head shape that results. A hard, raised ridge will form along the sagittal suture, and the child’s head growth will slow or stop. A diagnosis is made after a physical examination of the child’s head followed by x-rays and possibly a computerized tomography, or CT, scan.
The most common treatment of this type of craniosynostosis is surgery. The procedure is typically performed while the patient is still an infant and involves removing, reshaping, and replacing the deformed bone. Surgery will help alleviate pressure on the brain, create room for the brain to properly grow to its full size, and improve how the head looks. Surgery is generally effective for most patients, especially those without other genetic syndromes or health problems.
The cause of sagittal craniosynostosis is not well understood. It is possible that genetics plays a role in developing this type of craniosynostosis. It can occur with other defects and with genetic disorders like the Crouzon, Apert, and Carpenter syndromes. An individual with a family history of sagittal craniosynostosis may consider consulting with a genetic counselor prior to having children.
If sagittal craniosynostosis is not corrected, the head deformity can become severe and permanent. The child may experience seizures, developmental delays, and increased intracranial pressure. Parents with children whose heads have an unusual shape should contact their health care providers and secure a consultation with a pediatric neurosurgeon or neurologist if warranted.
