Craniosynostosis

Definition

A congenital disorder in which premature closure of the sutures (gaps) on the skull results in an abnormally shaped head. The severity of symptoms and shape of the skull depend on which bones are affected. Synostosis means a union of adjacent bones.

Synonyms include: craniostenosis, plagiocephaly, scaphocephaly, and trigonocephaly.

Description

Craniosynostosis consists of deformities of the skull resulting from premature closure of the gaps, or sutures, between the skull bones.

Normally, the bones of the skull are not joined at birth, allowing the head to grow evenly. In individuals with craniosynostosis, the sutures where the skull bones meet have closed, or close prematurely. As a result, the expanding skull bones grow abnormally, and the abnormal skull shape becomes more pronounced as the infant grows. The shape is dependent on which sutures have closed, and various abnormalities have specific names.

Acrocephaly, oxycephaly, turricephaly denote a pointed (high) head, caused by the premature closure of all sutures.

Brachycephaly denotes an abnormally short, squat skull, caused by the premature closure of the two coronal sutures, which cross the top front portion of the skull, width-wise.

Dolichocephaly and scaphocephaly denote an abnormally long front-to-back distance of the skull, caused when the sagittal suture, which runs lengthwise along the top of the skull, is closed.

Plagiocephaly denotes a somewhat lopsided, asymmetric, pointed appearance, caused by premature closure of sutures that cross the top of the skull widthwise (coronal sutures in the front, lambdoidal sutures in the back), on only one side.

Trigonocephaly denotes a triangular shape at the top of the skull, caused by the closing of the metopic suture, which runs lengthwise along the top front of the skull, forward of the sagittal suture and anterior fontanelle (the "soft spot" at the top front portion of an infant's skull).

Causes and Risk Factors

Craniosynostosis is estimated to occur in one in 2,000 live births. The cause is unknown in most children. However, genetic syndromes account for 10 to 20 percent of cases.

More than 50 craniosynostosis syndromes and more than 20 conditions in which craniosynostosis is a secondary or occasional feature have been described.

Symptoms

There is rarely any neurologic deficit. Mental retardation may occur in these disorders and is more likely in cases where the closure of the sutures is greatest.

Diagnosis

Most of the cases are evident at birth.

Treatment

Among the majority who do not exhibit neurologic complications or mental retardation, there are few complications caused by this disorder other than cosmetic and sociopsychological problems. The craniosynostoses may be treated surgically by removing the affected suture(s).

Questions to Ask Your Doctor

What type of craniosynostosis is involved?

Which suture is involved?

Where is it located?

Is there any evidence of neurologic complications?

What treatment do you recommend?

Is surgical correction indicated?