It was noted in the 19th century that normal skull growth occurs in a direction perpendicular to the sutures and therefore premature fusion of a suture will cause a predictable abnormal head shape. Decades of research since then have shed much light on the mechanisms of craniosynostosis. It is reconginzed that gestations involving multiple babies, large birth weight, oligohydramnios (low amount of amniotic fluid) and advanced maternal age are at increased risk of developing craniosynostosis.
The basic underlying mechanism likely involves compression of the cranium while the fetus is in the uterus and this in turn stimulates the dura (lining of the brain) to produce bone prematurely at the suture. Genetics likely plays a role as well, as studies comparing identical (monozygotic) and fraternal (dizygotic) twins show an increased incidence in the identical twin group.
Treatment of cranial abnormalities, whether they be from premature fusion of one or more sutures or from deformation, begins with an evaluation by a multidisciplinary craniofacial team. An ophthalmologic and hearing evaluation is important and routinely part of the team work-up for our New York craniosynostosis patients. Some cases require imaging studies (CT, MRI, Ultrasound, X-ray) to evaluate the bones and brain.
Correction is aimed at treating the underlying cause. In cases of deformational plagiocephaly or brachycephaly, positional changes and “tummy-time” are a couple of common first-line therapies. Molding helmets are sometimes used as well. In more severe cases of deformation, surgery may be necessary to correct the head shape.
In cases of craniosynostosis, the prematurely fused suture can be treated in different ways. In very mild cases with no signs of growth constriction of the brain, surgery may not be necessary. In moderate to severe cases, the fused suture can be surgically removed and a molding helmet worn postoperatively (strip craniectomy), or a more traditional cranial vault remodeling (CVR) may be performed. The latter involves removing the fused suture and molding the skull bones to create a normal head shape. The determination of which surgery is most appropriate, as well as the specifics of the preoperative, operative, and postoperative course is a discussion that parents will have with their craniofacial surgeon and the rest of the team.