Craniosynostosis is a rare condition in which a baby develops or is born with an abnormally shaped skull. It happens as a result of one or more of the infant’s cranial sutures (cracks in the skull) fusing too early. Normally an infant’s skull is made up seven bones, with gaps (cranial sutures) between them that do not fuse until the child is approximately two years old, this allows their brain to grow and develop. When there is no other involvement besides the skull plates, the cause is usually unknown and the condition is called Non-Syndromic Craniosynostosis. When a suture closes prematurely, a predictable abnormality of head shape occurs due to compensatory expansion required by the growing brain. A skilled geneticist can determine if a child’s craniosynostosis is syndromic or non-syndromic.
Cranial sutures involved in non-syndromic craniosynostosis include:
– Metopic Craniosynostosis
– Sagittal Craniosynostosis
– Coronal Craniosynostosis
– Lambdoid Craniosynostosis
The treatment of craniosynostosis is surgical. In a small percentage of cases surgery is mandated by an increase in intracranial pressure due to changes in head shape, configuration and volume. However most cases are treated because of the resulting aesthetic deformities, and the team efforts of a craniofacial plastic surgeon and neurosurgeon can optimize the cosmetic outcome.
Metopic Craniosynostosis is one of the more common forms of this disorder, accounting for approximately 40% of all single-suture synostosis. The metopic suture lies along the midline of the forehead and, when fused prematurely, leads to a ridge in the middle of the forehead and a triangular shape to the skull (trigonocephaly). A small fraction of these patients will have increased intracranial pressure and other neurologic abnormalities. Correction is usually recommended for improvement in the cosmetic appearance as well as to address any possible underlying neurologic concerns.Metopic craniosynostosis is usually corrected for cosmetic reasons and an experienced craniofacial plastic surgeon will assure a strong focus on this objective.
Characteristics of metopic craniosynostosis include:
– Triangular shape of the anterior skull
– Triangular shape of the orbits
– Orbital hypotelorism
– Narrowing between the temples
Sagittal Craniosynostosis is one of the more common forms of this disorder, and like the metopic form, it accounts for approximately 40% of all single-suture synostosis. The sagittal suture lies along the midline of the skull. When this suture fuses prematurely, the head cannot grow in width, but must grow in length to accommodate the expanding brain.Sagittal Craniosynostosis can be corrected within the first year of life using new endoscopic techniques and biodegradable technologoy.
Characteristics of sagittal craniosynostosis include:
– Elongated skull shape (front to back)
– Narrow skull shape (side to side)
– Midline bony ridge
– Frontal bossing
– Occipital prominence
Coronal Craniosynostosis is a premature closure of the skull sutures that lie behind the forehead and run from side to side. Coronal craniosynostosis may be unilateral or bilateral. When both coronal sutures are involved, it is more likely that an underlying syndrome is present.
Characteristics of coronal craniosynostosis include:
– Flattening of one or both sides of the forehead
– Increased forehead height
– Widening of the skull (side to side)
– Recession of one or both brows
Lambdoid Craniosynostosis is quite rare and occurs in only 2-4% of patients with craniosynostosis. The lambdoid suture is located along the back of the head and it may fuse prematurely on one side or on both sides. Typically, fusion will cause the skull to develop a trapezoid shape, indicating restricted growth at the fused suture and compensatory growth changes surrounding the suture.It is important to differentiate lambdoid craniosynostosis from positional head deformation in the first months of life.
Characteristics of lambdoid craniosynostosis include:
– Ridging over the fused lambdoidal suture
– Contralateral frontal bossing
– Posterior displacement of the ipsilateral ear
– Ipslateral occipitomastoid bulge