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A congenital anomaly of the skull characterized by premature fusion of one or more cranial sutures.


Different morphological types of craniosynostoses: 1. trigonocephaly; 2. scaphocephaly; 3. plagiocephaly; 4. brachycephaly; 5. oxycephaly. (Modified from Bissonnette B, Dalens B: Pediatric Anesthesia, McGraw-Hill, 2002, p. 1334, with permission).


Craniosynostosis resulting in keel-shaped forehead (trigonocephaly) in a young boy.


Estimated to be approximately 1:200,000 live births. Sagittal and lambdoid craniosynostosis (the most common type) are approximately four times more common in males than in females, whereas unicoronal craniosynostosis is more common in females. For the other forms, the distribution is about equal between the two genders.

A positive family history is present in up to 40% of cases, with genetic syndromes accounting for at least 50% of those cases. The most common syndromes include Apert Syndrome and Crouzon Syndrome. Both autosomal dominant and autosomal recessive inheritance have been described, but sporadic occurrence also is common. Genetic mutations that may be responsible for craniosynostosis include mutations in the fibroblast growth factor receptors (FGFR1, FGFR2, FGFR3), the TWIST, and MSX2 genes.

The etiology is unknown but may involve abnormal cranial suture development resulting in failure of growth perpendicular to the affected suture and overgrowth of skull parallel to the affected suture. Environmental factors etiologically linked to craniosynostoses include rickets and hyperthyroidism. Drugs that may be involved in craniosynostosis include phenytoin, retinoids, valproic acid, aminopterin/methotrexate, fluconazole, and cyclophosphamide. In some cases, local intrauterine factors related to constraint of the fetus (e.g., abnormal positioning in utero, multiple pregnancy, oligohydramnios) have been linked to craniosynostosis. The developing brain is the driving power behind skull growth and forces the skull to compensatory growth in directions perpendicular to the fused suture along adjacent open sutures.

The diagnosis may be suspected clinically if special attention is paid to the head circumference (percentiles), shape and presence of any deformities, size of the fontanelles, palpable ridges over affected sutures with absent movement of the bone on either side of the suture on palpation, neurologic behavior and development of the infant, the pupils and their reaction to light, and funduscopic evaluation for papilledema. Radiologic examinations (e.g., computed tomography scanning and/or magnetic resonance imaging) confirm the diagnosis. True craniosynostosis must be differentiated from birth molding (present at birth and resolving within days or weeks) and positional plagiocephaly without synostosis (a frequent finding resulting from local pressure on a specific area of the skull (same position), typically the occipital region leading to occipital or lambdoid plagiocephaly.

It must be differentiated between syndromic and nonsyndromic craniosynostosis. Nonsyndromic cases account for approximately 50% of all craniosynostoses and are commonly limited to synostoses of a ...

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