Craniosynostosis

A condition in which one or more of the fibrous sutures in an infant skull prematurely fuses.

Craniosynostosis affecting the skull shape.

Craniosynostosis is a birth defect in which the bones in a baby’s skull join together too early. This happens before the baby’s brain is fully formed. As the baby’s brain grows, the skull can become more misshapen. The spaces between a typical baby’s skull bones are filled with flexible material and called sutures. These sutures allow the skull to grow as the baby’s brain grows. When one or more of the sutures closes too early, it changes the growth pattern of the skull.

Types

Craniosynostosis can affect one or more of the sutures in a baby’s skull. The types of craniosynostosis are named according to the sutures involved.

Sagittal synostosis

Diagram of single suture synostosis.

The most common type of craniosynostosis is sagittal synostosis. It affects the suture that runs from front to back at the top of the skull. This causes the head to grow long and narrow, a condition known as scaphocephaly.

Coronal synostosis

Coronal synostosis affects one or both of the sutures that run from ear to the top of the skull. If one suture is affected, it is called unilateral coronal synostosis, leading to plagiocephaly. If both sutures are affected, it is called bilateral coronal synostosis, leading to brachycephaly.

Metopic synostosis

Metopic synostosis affects the suture that runs from the top of the head down the middle of the forehead, toward the nose. This can cause a triangular-shaped forehead, known as trigonocephaly.

Lambdoid synostosis

Plagiocephaly due to lambdoid synostosis.

Lambdoid synostosis is the rarest form and affects the suture at the back of the head. It can cause the head to flatten on one side, leading to posterior plagiocephaly.

Causes

The exact cause of craniosynostosis is not known. It can occur as an isolated condition or as part of a syndrome. Genetic factors may play a role, and certain mutations have been associated with syndromic craniosynostosis.

Syndromic craniosynostosis

Craniosynostosis can be part of a genetic syndrome. Some of the syndromes associated with craniosynostosis include:

Crouzon syndrome

Patient with Crouzon syndrome.

Crouzon syndrome is characterized by the premature fusion of certain skull bones, leading to abnormal head shape, facial anomalies, and sometimes exophthalmos.

Apert syndrome

Apert syndrome involves craniosynostosis, syndactyly (fusion of fingers and toes), and other skeletal abnormalities.

Carpenter syndrome

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Patient with Carpenter syndrome.

Carpenter syndrome is a rare condition that includes craniosynostosis, obesity, and other skeletal abnormalities.

Diagnosis

Diagnosis of craniosynostosis is typically made through physical examination and imaging studies such as X-ray or CT scan. These imaging techniques can help determine which sutures are affected and the extent of the condition.

Treatment

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Osseous deformity due to untreated craniosynostosis.

Treatment often involves surgery to correct the shape of the skull and allow for normal brain growth. The timing and type of surgery depend on the severity of the condition and the sutures involved.

Prognosis

With early diagnosis and treatment, most children with craniosynostosis can have normal cognitive development and a good quality of life. However, untreated craniosynostosis can lead to increased intracranial pressure and developmental delays.

Related pages

• Suture (joint)
• Skull
• Congenital disorder