Plagiocephaly is a deformity of the infant’s skull making it asymmetrically shaped, often referred to as “flat head syndrome”. In the vast majority of cases, it is a benign abnormality that resolves before the age of two and results from lying on the baby’s back. But, much more rarely, this asymmetry is the result of the premature welding of one or more cranial sutures, a craniosynostosis, which may require a surgical operation.

The so-called positional plagiocephaly is characterized by a flattening of the occiput (the back of the skull) on the side corresponding to the orientation of the head during sleep, hence the expression of flat head syndrome. The infant’s head then takes the form of a parallelogram. A study whose results are relayed by the Canadian Pediatric Society shows that 19,7% of infants have positional plagiocephaly at the age of four months, then only 3,3% at 24 months. (1) When craniosynostosis is involved, the deformity of the skull varies depending on the type of craniosynostosis and the sutures it affects.

By far the most common cause of plagiocephaly is positional plagiocephaly. Its frequency of occurrence has exploded in the United States and Europe since the 90s, to such an extent that the press, like doctors, speak of an “epidemic of flat skulls”. It is now clear that the origin of this epidemic is the campaign ” Back to Sleep Launched in the early 90s by the American Academy of Pediatrics to fight sudden infant death syndrome, which advised parents to put their infants on their backs exclusively during the first year of life. It is important to emphasize that this benign epidemic does not in any way call into question the “sleep on the back” which makes it possible to limit the risk of sudden death.

Craniosynostosis is a much rarer cause of cranial asymmetry than positional plagiocephaly. It causes premature welding of the bones of the baby’s skull, which can disrupt the proper development of his brain. This congenital ossification defect is a simple anomaly isolated in the vast majority of cases, but craniosynostosis can be associated with a cranial syndrome, resulting from a genetic anomaly (the mutation of the FGFR gene), such as Crouzon and from Apert.

In addition to lying on the back (supine) for sleeping and sleeping with your head on the same side, other risk factors for plagiocephaly are clearly identified. Boys are more affected than girls, almost 3/4 of infants with positional plagiocephaly being boys. (2) This is explained by their lower activity in the first months of life, with periods of awakening on the stomach not frequent enough (less than three times a day). The researchers also identified as a risk factor the place of the eldest in the family, a stiff neck which limits the rotation of the neck, as well as exclusive bottle-feeding.

The risk of developing cranial deformities can be reduced by increasing the infant’s positions and the orientations of his head. During the phases of sleep, while lying on the doc (supine), when the baby shows a clear preference for the same side, the technique to encourage him to turn his head is to change the baby’s orientation in the bed alternately each day, towards the head or the foot of the bed. Let us recall once again that the dorsal decubitus makes it possible to limit the risk of sudden death and should not be called into question because of a benign affection which often resolves from the age of two!

During his waking phases, the baby should be placed in various positions and placed on his stomach (in prone position) for about a quarter of an hour several times a day. This position helps in the development of the cervical musculature.

Physiotherapy treatment including developmental stimulation exercises can complement these measures. It is particularly recommended when a stiff neck prevents the infant from turning his head.

In cases where the head asymmetry is severe, an orthosis treatment is used, which consists of wearing a mold helmet for the infant, up to a maximum age of eight months. However, it can cause inconvenience such as skin irritation.

Surgery is only necessary in cases of craniosynostosis.