Understanding Craniosynostosis

baby handIn normal circumstances, how does the brain and skull develop for appropriate growth in a newborn? The brain grows rapidly in utero and during the first three years of life. An infant born at term has nearly 40 percent of his/her adult brain volume, and this increases to 80 percent by age of three. The growth of skull bones is driven primarily by the expanding growth of the brain.

Full-term infants have well-formed skull bones separated by strips of connective tissue, sutures and fontanelles (the soft spots on top of the head). The skull of an infant or young child is made up of bony plates that allow for the skull’s growth. The borders at which these plates intersect are called sutures or suture lines. The sutures and fontanelles close at different times. However, early closing of a suture causes the baby to have an abnormally shaped head.

Craniosynostosis is the premature fusion of one or more of the cranial sutures and can occur as part of a syndrome or as an isolated defect (nonsyndromic). Craniosynostosis is called “simple” when only one suture is involved and “compound” when two or more sutures are involved. In the past, the prevalence of craniosynostosis was estimated to be one per 1,800 to 2,200 births, but recent evidence puts the estimate even higher.

Types of craniosynostosis:

  • Sagittal synostosis (scaphocephaly) is the most common type. Babies with this type tend to have a broad forehead. It is more common in boys than girls. It affects the main suture on the very top of the head. The early closing forces the head to grow long and narrow, rather than wide.
  • Frontal plagiocephaly is the next most common type. It affects the suture that runs from ear to ear on the top of the head. If the condition is more obvious from the front, it is called deformational frontal plagiocephaly (DFP), in which one side of the forehead is flat; if it involves the back of the head, which is flat on one side, it is called deformational posterior plagiocephaly (DPP). It is more common in girls.
  • Metopic synostosis is a rare form that affects the suture close to the forehead. The result is a triangular shaped forehead. It may range from mild to severe.

There is usually no family history of the condition. However, premature birth and low birth weight have been associated with craniosynostosis. There is a hereditary component in such genetic disorders commonly linked to craniosynostosis, including Crouzon, Apert, Carpenter, Chotzen, and Pfeiffer syndromes. Despite the resulting abnormalities caused by the condition, most children with craniosynostosis are otherwise healthy and have normal intelligence.

Commonly, craniosynostosis is present at birth, but it is not always diagnosed when mild. Usually it is diagnosed as a cranial deformity in the first few months of life. The diagnosis relies on physical examination and radiographic studies, including x-rays and computed tomography (CT).

Symptoms depend on the type of craniosynostosis. In infants with this condition, changes in the shape of the head and face may be noticeable. The appearance of the child’s face may not be the same when compared to the other side. Other clinical findings may include the following:

  • a full or bulging fontanelle (soft spot located on the top of the head)
  • a raised hard ridge along the affected sutures
  • unusual head shape
  • increasing head circumference
  • slow or no increase in the head size over time as the baby grows
  • sleepiness (or less alert than usual)
  • scalp veins very noticeable
  • increased irritability
  • high-pitched cry
  • poor feeding
  • projectile vomiting
  • seizures
  • bulging eyes and an inability of the child to look upward with the head facing forward
  • developmental delays

The key to treating craniosynostosis is early detection and treatment. Some forms of craniosynostosis can result in impacting the brain and development of a child. The degree of the problem is dependent on the severity of the craniosynostosis, the number of sutures that are fused, and brain problems or other organ system problems that may affect the child.

Optimal care of infants with craniofacial anomalies requires a multidisciplinary team approach. Infants should be evaluated within the first few weeks of life. However, referral to ANA, for example, is appropriate at any age. Once the diagnosis of craniosynostosis has been confirmed, the treatment is surgical correction. The best time to intervene is when the infant is between three and nine months of age. However, infants with symptoms and signs of increased intracranial pressure require urgent surgical decompression.

The purpose of surgery is to relieve any pressure on the brain and make sure there is sufficient room in the skull for the brain to grow properly. In addition, surgery improves the appearance of the child’s head.
If your child’s pediatrician has expressed concern, if you feel for any reason that your child’s head shape is unusual or not growing well, or if he/she displays the above signs or symptoms, contact us at Advanced Neurosurgery Associates. In the meantime, you can see the results of treatment for this condition on a revealing patient video:

 
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