Non-syndromic Craniosynostosis is a non-inherited, isolated finding without related anomalies such as disorders of the limbs, ears or cardiovascular system. It typically involves the early closure of a single growth suture in your child's skull.
In a small percentage of cases craniosynostosis is found together with several other congenital conditions referred to as syndromic craniosynostosis. The majority of patients with craniosynostosis are non-syndromic craniosynostosis. This occurs in about one in 2,500 births. The metopic suture is the only cranial suture that normally closes before adulthood. The metopic suture usually closes at about 6-9 months of age. All of the other cranial sutures should remain open into adulthood, long after the brain has stopped growing.
A baby's skull has 6 major cranial sutures. The metopic and sagittal sutures run in the center of the skull from front to back. There are 2 coronal and 2 lambdoid sutures that extend from the ends of the sagittal suture down to the skull base.
An infant's brain is growing very quickly, more than tripling in size in the first two years of life. The growing brain "stretches" the cranial sutures that stimulates the sutures to make more bone and cause the skull bones to grow and make more space inside the skull for the growing brain. This system allows the skull to remain just large enough for the brain it protects. Any of these sutures may close earlier than normal.
In craniosynostosis a cranial suture closes earlier than it should which restricts growth of the skull bones in the area of the closed suture. This is a problem because the brain continues to grow at the same pace. The remaining open cranial sutures must make up the difference and grow more bone to create enough space for the growing brain. Closure of each of the major sutures causes a recognizable pattern of abnormal growth and abnormal head shape. The position of the closed and remaining open sutures determines how the skull will grow and what the shape will be.
The two biggest concerns related to craniosynostosis are the risk of elevated pressure inside the skull and the emotional and psychosocial effects of skull deformity. As stated above, even when the sutures close prematurely, the brain continues to grow at the same rate. Therefore, the remaining open sutures must grow faster to create enough space inside the skull for the growing brain. In about 15 out of 100 patients with one prematurely closed cranial suture (single suture craniosynostosis) the skull does not grow fast enough to keep up with the rapid growth of the brain. This results in an increased pressure inside the skull that can be harmful to the health of the brain. This is called elevated intracranial pressure (ICP). The more closed sutures there are, the higher the likelihood that the skull will not be able to grow fast enough. When two sutures are closed the risk of elevated intracranial pressure is over 40%. Very high pressure in the skull can cause learning delays and blindness.
When craniosynostosis affects any of the cranial sutures increased growth occurs in the remaining open sutures (compensatory growth) that results in an abnormal head shape. The abnormal head shape is characteristic and predictable for each closed suture. The names for the most common forms of craniosynostosis are listed below:
- Sagittal suture closure – Scaphocephelay
- Metopic suture closure – Trigonocephaly
- One Coronal – Anterior Plagiocephaly
- One Lambdoid Suture – Posterior Plagiocephaly
- Two Coronal Sutures - Brachychephaly
|TREATMENT & MANAGEMENT|
Treatment of single suture or poly-suture non-syndromic craniosynostosis depends on the suture involved, the extent of the anomaly, and the age of your child.
Left untreated, 10 to 15 percent of patients with single suture synostosis will go on to develop elevated intracranial pressure that will require surgery. These craniofacial anomalies can also result in severe physical differences that patients find very difficult to live with. Surgery can help address these problems.
In mild cases of craniosynostosis, surgery may not be required. For example, the metopic suture normally closes between 6 and 8 months of age. If it closes slightly early, it may cause a small ridge without any distinct changes in the shape of the skull. In these cases your child’s medical team may recommend conservative observation to monitor for any necessary treatment.