Sagittal Synostosis (Scaphocephaly) Causes

Sagittal Synostosis is one of several forms of craniosynostosis, a congenital birth defect that is characterized by premature closure of the gaps, or “sutures” between the sections of a newborn’s cranium.  Babies are born with fibrous seams between the six sections of the cranium that are designed to allow for growth of the cranium and the brain within it.  Premature closing of one or more of these sutures is described as craniosynostosis.  Closure of the sagittal suture is known as sagittal synostosis or scaphocephaly.

The sagittal suture runs from the top of the cranium, the soft spot in the middle of a newborn’s head, to the rear of the skull.  Premature closure of this seam results in a narrowing of the skull to the rear and conversely, the development of a broader forehead and front of the cranial structure.   This is the opposite of normal development, wherein the back of the head is wider than the front.  Scaphocephaly is a term for an abnormally shaped long narrow head, the result of sagittal synostosis that goes untreated.

Types of Scaphocephaly Birth Defects

There are several types of this malformation, depending on what portion of the sagittal suture fuses prematurely.  If the anterior portion of the suture (that section towards the front of the skull) closes, the narrowing of the cranium will result in frontal bossing, meaning a prominent or protruding forehead.  The surgical intervention in this situation is quite extensive, requiring a surgical expansion of the narrowed skull and reconstruction of the forehead area.

If the posterior portion of the sagittal suture closes, the resulting malformation is different as are the surgical methods required to correct it.  The most common manifestation of this type of scaphocephaly is the development of the occipital knob, a condition that may roughly be described as an overgrowth of the rear of the cranium.  This “knob” extends from the back of the head and is corrected by surgical removal, shortening the skill, and restoration of the rear of the infant’s cranial surface.  A more extreme version of this malformation is called the “golf tee” deformity which requires removal of the deformity and widening of the occipital region.

Complete sagittal synostosis, meaning total closure of the sagittal suture, requires surgical removal and reconstruction of the frontal bossing and the occipital knob.  In addition the cranium must be widened in order to relieve the abnormal narrowing.  This surgical procedure is a complex procedure that requires several reconstructive techniques.

Scaphocephaly Mental Prognosis

One of the issues surrounding this type of craniosynostosis is the impact on mental function that the increased pressure on the brain may cause.   Unnatural narrowing of the skull does not allow for normal brain growth in infancy without creating pressure on the tissue within the cranium.  There have been several studies on the impact of surgical repair for sagittal synostosis abnormalities.  The conclusion reached by most pediatric surgeons and the research in the field is that early treatment of scaphocephaly can result in normal brain development, whereas later treatment may allow for some impact on the development of various neurological functions.