Craniosynostosis

Craniosynostosis is a congenital defect that is present at birth. It occurs when the bones of the skull fuse before the brain has fully developed.

The brains of healthy infants are surrounded by several bony plates connected by flexible joints (sutures) that allow the skull to adapt to brain growth. These sutures normally close once the skull has reached its final size, around two to three years of age. Craniosynostosis may affect all joints or only one. In these cases, the brain continues to grow toward the open sutures, causing the head to develop an abnormal shape.

Depending on which sutures close prematurely, there are several types of craniosynostosis:

• Sagittal craniosynostosis: the sagittal suture, which extends from the front to the back of the head along the top of the skull, closes prematurely. This is the most common type.
• Coronal craniosynostosis: premature fusion of the coronal sutures located on both sides of the head, extending from the ear to the sagittal suture.
  • Unicoronal craniosynostosis: only one coronal suture is affected.
  • Bicoronal craniosynostosis: both coronal sutures are affected.
• Lambdoid craniosynostosis: the lambdoid suture located at the back of the head closes prematurely.
• Metopic craniosynostosis: affects the metopic suture, which extends from the nose to the sagittal suture.

The development of complications depends on the number of sutures involved, the age at which they fused, and whether the brain has sufficient space to expand. Nevertheless, the prognosis for patients with craniosynostosis is generally favorable. Most patients experience normal development after surgical intervention, and life expectancy is not reduced.

Symptoms

The hallmark symptom of craniosynostosis is skull deformity, with the head taking on a characteristic shape depending on the affected sutures:

• Sagittal craniosynostosis: the head becomes long and narrow (scaphocephaly).
• Coronal craniosynostosis: the forehead flattens, the eye socket is elevated, and the nose may become slightly elongated.
  • Unicoronal craniosynostosis: facial features are displaced toward the affected side.
  • Bicoronal craniosynostosis: the head becomes short and broad (brachycephaly).
• Lambdoid craniosynostosis: causes posterior plagiocephaly, characterized by flattening of the back of the head.
• Metopic craniosynostosis: the front of the head narrows while the posterior region widens (trigonocephaly).

Unless associated with other health conditions, children with craniosynostosis typically do not present additional symptoms and have normal intellectual development for their age.

Causes

The exact causes of craniosynostosis remain unknown, although a genetic component is believed to play a role in its development. However, it is not necessarily hereditary.

Depending on its origin, craniosynostosis can be classified into two types:

• Nonsyndromic craniosynostosis: the most common form. It is not associated with any genetic syndrome and is thought to result from a combination of environmental and genetic factors.
• Syndromic craniosynostosis: a group of rare disorders characterized by premature fusion of cranial sutures, craniofacial deformities, and abnormalities in the development of the neurological and musculoskeletal systems. The best-known syndromes include Apert syndrome, Pfeiffer syndrome, and Crouzon syndrome.

Risk Factors

The risk of craniosynostosis is higher in the following situations:

• Apert syndrome: in addition to premature cranial suture fusion, there is fusion of the fingers and toes, dental crowding, palate deformities, and delayed early learning.
• Pfeiffer syndrome: premature closure of cranial sutures associated with prominent eyes, a depressed palate, underdevelopment of the upper jaw, thumb fusion, extra digits, intellectual disability, growth problems, or congenital heart disease.
• Crouzon syndrome: characterized by premature cranial suture fusion, underdeveloped maxilla, small mandible, malocclusion, high-arched palate, breathing difficulties, widely spaced and prominent eyes, or hearing loss.
• Genetic predisposition.
• Some studies suggest that exposure during pregnancy to certain medications, such as clomiphene citrate or methotrexate, may contribute to premature fusion of the cranial sutures.

Complications

Craniosynostosis can lead to permanent skull deformity and, consequently, low self-esteem, social isolation, or depression.

In cases that are not treated promptly or that occur as part of a genetic syndrome, increased intracranial pressure may develop, potentially resulting in developmental delays, learning difficulties, memory impairment, reduced reasoning ability, seizures, headaches, or blindness.

Prevention

Craniosynostosis cannot be prevented. To reduce the risk of complications, attendance at routine newborn check-ups is recommended, as these evaluations are designed, among other purposes, to detect congenital health conditions.

Which specialist treats Craniosynostosis?

Craniosynostosis is treated within the specialties of Pediatric neurology or Neurosurgery.