The Browns brought their infant in for her routine well visit. They were obviously concerned about something; you could feel the tension in the room. When I asked if everything was all right they looked at each other, and dad spoke, “We are worried about her head. She has a flat head and it has us concerned.”
Since their baby had very little hair at this stage, it was obvious what they were talking about. She did indeed have a flattened head. But it did not look out of the ordinary. I examined her carefully, and was able to acknowledge from the parents that she spends a great deal of time on her back. I assured them that her head was flattened because of this “mechanical” effect, and nothing more.
Dad then went on to explain, “I was talking to a co-worker, and he told me about a friend whose baby’s head was flat. And this baby had to have major surgery by a neurosurgeon. It was a big deal. The baby was in the intensive care unit for a week, and had to have blood transfusions.” After hearing this, I realized why the parents were so concerned. I asked dad if the friend’s baby had craniosynostosis. “That’s it!” he said emphatically.
I explained that there was a big difference between true craniosynostosis and a flat head from positional causes. To better understand these differences I felt it was of value to discuss the normal development of the skull.
The skull is a bony structure that is designed to protect the brain in utero, and is malleable or can mold to allow passage through the birth canal. It must accommodate expansion caused by rapid brain growth during the first few years of life. The skull has numerous plate-like bones that are joined together by structures known as sutures. These are immobile contact points between the bones that allow for growth and molding. The fontanels are the points at which the suture lines cross. The anterior fontanel, know as the “soft spot”, is the junction of the coronal and sagittal sutures.
The pressure exerted by the growing brain pushes the skull bones apart, causing new bone to be laid down along the suture lines. This bone is deposited and resorbed continually which allows the skull to remodel itself as the brain grows. Rapid brain growth of infancy is nearly complete by the second year of life, and the sutures are largely ossified by eight years of age. Complete bony union of the skull is fully concluded by twenty years.
As the suture lines project across many planes, the skull can grow in all directions. At any suture line, the skull grows perpendicularly to the suture. Growth along the sagittal suture, for example, increases the width of the skull. Growth along the coronal suture increases the skull’s anterior-posterior diameter.
Craniosynostosis, by definition, is the premature closure of the fontanel. When this occurs, normal growth or expansion of the skull is interfered with, and there is a compensatory growth along the “open” sutures. This causes the skull to become misshapen. This condition occurs in approximately 1-2/1000 births. In the United States, the male-to-female ratio is about 3:2, with a particularly high prevalence of sagittal synostosis in males. Approximately 85 percent of cases occur in Caucasians. The cause of craniosynostosis is not known, but environmental and genetic factors are sure to play a role. At least sixty recognized syndromes have been associated with craniosynostosis.
Craniosynostosis can be diagnosed with imaging studies such as skull X-rays or a CT scan. Early detection is important because surgical intervention is the treatment of choice. This is preferably done as early as possible, 6-12 months of age. By one year of age the child’s skull is 85 percent of its adult size. It is considered a major surgery, requiring the expertise of a neurosurgeon or plastic surgeon, and blood transfusions are usually required. In experienced hands the results are amazing.
In the case of Mr. and Mrs. Brown, their baby did in fact have a flattened head. But it was because the baby spent a good portion of time sleeping in a prone position--on her back. Since the American Academy of Pediatrics has instituted the “Back to Sleep” program which promotes having the babies sleep in this position and not on their tummies, the incidence of Sudden Infant Death Syndrome, or crib death, has dramatically declined. But more and more pediatricians are seeing infants with flattened heads as a result of this. This positional deformity is benign and largely self-correcting. Without any intervention, these usually resolve on their own. Once the hair comes in, whatever asymmetry occurs is imperceptible. To facilitate resolution of this positional deformity, certain physical maneuvers can enhance the re-molding of the skull. These include having the parents position their sleeping child so that the head does not rest on the flattened side. The infant can be placed on the stomach when she is awake and someone is with her. Physical therapy and helmet molding are available for more severe cases when indicated.
In evaluating an infant with a misshapen head, it is critical to determine if the child has a true craniosynostosis or not. This can usually be detected by a good physical exam, but if there are ANY questions, imaging studies should be done to confirm this. If a diagnosis of craniosynostosis is made, immediate referral to the appropriate surgeon should take place. In the case of the Browns their daughter had a mildly misshapen head as a result of sleeping prone. Her exam was normal, yet to allay her parent’s fear we did do an X-ray, that was also normal. But it was well worth the peace of mind that it afforded mom and dad. “I’ll just be glad when she gets some hair,” her mom said jokingly.