When babies are born, their skull consists of six plates designed to partially overlap with one another, which allows the head to temporarily contract and fit through the birth canal. As the brain grows and expands over the first several months of life, the plates eventually slide back out and flatten. The edges of the plates come together in joints (called sutures) and allow for the rapid growth of the brain over the first two years, and eventually begin to close (fuse). As these sutures close and the cranial bones harden, there is less opportunity for cranial growth.
During these first two years, the child's skull is soft and vulnerable, leaving them at risk for developing abnormal head shapes. If left untreated, these abnormalities can lead to other medical issues later in life.
What Causes Head Shape Anomalies?
There are typically three main causes of abnormal head shapes:
Pressure on an Infant’s Head with Respect to the Baby’s Position
This group makes up the largest number of infants with an abnormal head shape; these abnormal head shapes usually develop during pregnancy or while the baby is sleeping.
The most common head shape anomaly is positioning-related flattening, sometimes called positional plagiocephaly, a disorder in which the back or one side of an infant's head is flattened. Sometimes this is more prominent on one side, with a bulge on the other side. There can also be an offset to the ears when viewed from the top. This asymmetry is caused when too much pressure is placed on one side of the head. Also, pediatricians have noted an increase in infants whose heads are flattened in the back since the “Back to Sleep” campaign was initiated in 1994 to prevent sudden infant death syndrome.
A variety of factors may be involved in positional plagiocephaly. The most common factors are:
- Preferential sleep position (such as on the back), extended time in car seats or baby play saucers, etc.
- Torticollis (also known as wryneck), a tightening of the neck muscle that causes infants to favor sleeping on one side of the head
- Intra-uterine positioning that occurs when a fetus positions itself in a constrictive area of the womb
- Multiple births, in which affects head position of the developing fetus in utero
Early Closure of the Skull’s Sutures
Called craniosynostosis, this is the next most common group of infants with abnormal head shapes. This condition is a rare kind of flattening and occurs when one or more of the joints between the cranial plates close prematurely. As the brain continues to grow, it forces the remainder of the skull to expand out of proportion, leading to an abnormal shape. Left untreated, craniosynostosis may also cause damage to the infant's brain.
The smallest group is infants with craniofacial syndromes, such as Apert's and Crouzon's. These children have craniosynostosis and facial bone abnormalities along with other deformities.
How Are Head Shape Anomalies Diagnosed?
Early evaluation and possible intervention are important to the successful management of head and facial abnormalities. The decision to seek evaluation and possible treatment should be made as early as possible.
How Are Head Shape Anomalies Treated?
- Treatment for positional plagiocephaly: Usually none is needed. Supervised “tummy time” for babies when they're awake or showing them toys and encouraging them to turn to either side is often effective. However, if necessary, children are sometimes fitted for a helmet, which helps correct the malformation.
- Treatment for craniosynostosis: Surgery, which is usually performed before the infant reaches nine months of age. In children with multiple affected sutures or with fusion of the plates that run in the center of the head from the front to the back (called sagittal craniosynostosis), surgery is often performed before the child reaches three months of age. Surgery involves removing the fused suture and repositioning the skull and/or face.
- Treatment for syndrome-related abnormalities: Surgery is usually required to correct the skull before the child reaches one-year-old and again between 6- and 8-years old to have the facial bones moved. These children have other disorders in growth of the facial skeleton in addition to fusion of the sutures of the skull, and surgery is often required on the face and jaws as the child grows.