Positional plagiocephaly, or flat head syndrome, is the term
for an abnormal shaped head caused by external pressures.
Most often this is seen as a flattening at one side of the
back of a baby’s head, giving an asymmetrical shape when
seen from above, or it is where the width and length of the
head are noticeably out of proportion – either abnormally
wide, or abnormally long.
While many babies are born with an abnormal head shape,
which comes as a result of the birth, most newborn heads
will revert to a normal shape by the time the baby is six
weeks old. If an abnormal shape persists or is not noticed
until after six weeks, it may be that the baby has
positional plagiocephaly.
There are a number of causes:
- in utero constraint – this is where the womb is
constricted somehow during pregnancy. This can happen when
there is more than one baby, when the mother has a small
uterus or pelvis, when there is too much or too little
amniotic fluid, and when a breech baby’s head is wedged
underneath the mother’s ribs
- prematurity – the skulls of premature babies can be very
soft and malleable, making the head more susceptible to
moulding due to external pressures
- torticollis – this is a condition in which a tight or
shortened muscle on one side of the neck causes the head to
tilt and/or turn to one side. It is usually present from
birth (congenital muscular torticollis) and may be obvious
or subtle. Torticollis can be caused by up to 80 different
pathologies. Most are benign and muscular torticollis is one
of these. Others are potentially life threatening if the
bones in the neck are damaged or not forming properly. It is
important to have suspected torticollis diagnosed properly
and to have it treated by a specialist physiotherapist.
- back sleeping and continual pressure on the back of the head
- since the advent of the “Back to sleep” campaign
(which began in the UK in November 1991), where
parents are advised to place their babies to sleep on their
backs to reduce the risk of sudden infant death syndrome
(SIDS/cot death), there has been a rise in positional
plagiocephaly. Because of the fear that many parents have of
cot death, babies these days spend an extended amount of
time on their backs – in car seats, Moses baskets,
pushchairs, bouncy seats and the like. Babies’ skulls are
soft in the first few months of life, and continual pressure
on one area of the head like this can cause it to flatten.
Torticollis and/or prematurity can worsen the flattening.
Positional plagiocephaly is the umbrella term for three
types of positional head deformity – plagiocephaly,
brachycephaly and dolichocephaly:
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With plagiocephaly, the side that is flattened will often
be accompanied by a prominent forehead, which when viewed
from above will give the head a parallelogram shape instead
of a normal symmetric oval shape. It is also common for the
baby to have misaligned ears - the ear on the affected side
may be pulled forward and down and be larger than the
unaffected ear. There is also sometimes asymmetry of the
face, with the affected side having a fuller cheek and a
more prominent appearance. Facial asymmetry can also include
a jawbone that is tilted, and an eye that appears displaced
and mismatched in size. Facial asymmetry is when one side of
the face does not match up with the other side. Essentially,
the face appears lopsided, or simply does not look right.
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Brachycephaly is diagnosed when the entire back of the head
is flat and the head has the appearance of being wide and
short (from front to back). There is sometimes bossing of
the forehead. Brachycephaly is most often seen when a child
sleeps entirely on the back of his head.
It is not uncommon to see a
combination of brachycephaly with plagiocephaly.
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Dolichocephaly is characterised by a long and narrow head
shape. It can result from extended time spent lying on the
side of the head, such as premature babies in neo-natal
units do. It can also be caused when the baby is in a breech
position during the pregnancy and the head becomes wedged
underneath the mother’s ribs (really called bathrocephaly,
but this term is little-known). In the US, these conditions
are both referred to as scaphocephaly, but technically, this
is where the baby has the same shaped head, but where it has
been caused by craniosynostosis, where the saggital suture
has fused prematurely. |
Technically, the word positional or deformational is used so
that the condition is differentiated from craniosynostosis,
which is a premature fusion of one or more of the skull
sutures (the gaps between the skull plates) and which
requires surgery. It is important that craniosynostosis is
ruled out before repositioning or helmet therapy is
considered. Paediatricians and helmet providers are skilled
at doing this. As a general rule, in positional
plagiocephaly, on the flattened side the ear is pushed
forwards, but with craniosynostosis, the ear on the
flattened side is pushed more towards the back of the head
than the other one.
However, if there is any uncertainty, a referral to one
of the four designated UK craniofacial units should be
sought. The units are at Alder Hey Children's Hospital in
Liverpool, Birmingham Children's Hospital, The Radcliffe
Infirmary at Oxford and Great Ormond Street Hospital in
London. These units are funded by the NHS's National
Specialist Commissioning Advisory Group (NSCAG) and are
called centres of excellence. It does not matter if you do
not live in the Primary Care Trust area of any of these
hospitals, as you can choose to seek assessment for your
child at any of them at no cost to your GP. The assessment
and any treatment necessary is funded by NSCAG. Some people
do choose to pay privately for advice, assessment and if
necessary treatment for craniosynostosis thinking that they
will get quicker treatment - but this is not true as GP's
referrals to any one of these units results in an
appointment within a month, if not sooner. Assessment most
typically takes the form of an X-Ray, CT or MRI scan to
check for craniosynostosis.
Great Ormond Street Hospital points out that “some reports
estimate that positional plagiocephaly affects around half
of all babies under a year old but to varying degrees.”
While mild cases of positional plagiocephaly can improve on
their own once a baby starts to gain mobility and spends
less time resting its head on hard surfaces, research
estimates that 1 in 15 cases of plagiocephaly will not have
resolved by the time a baby is one.
Early recognition of plagiocephaly is important. The
younger the child is when it is recognised, the better the
chances of stopping any progression.
Repositioning techniques
that give young babies
plenty of supervised “tummy time” during the day, and
ensure their heads are not always resting on the same area
will give them the best opportunity to grow up with a
normal-shaped head. Babies should still be placed to sleep
on their backs though, in line with the recommendations from
the Foundation for the Study of Infant Death, as the benefit
of reducing SIDS far outweighs any dangers due to positional
plagiocephaly.
If positional plagiocephaly still develops, or worsens,
older babies – over about five or six months old – can be
fitted with a custom-made helmet that naturally allows their
heads to come back to a normal shape as they grow.
If a baby has torticollis, then a referral to a
paediatric physiotherapist should be sought. Only once the
head regains full mobility can natural correction of head
shape can begin. Torticollis needs to be ruled out or
resolved for repositioning or helmet treatment to be fully
effective.
For more information on treatment options, see the
repositioning and
helmets pages.
Diagnosis of severity of plagiocephaly is determined by
taking measurements of the baby’s head by hand (or with an
optical scan). The private helmet providers all offer free
initial consultations that will give a diagnosis of
severity, but NHS hospitals and paediatricians do not seem
to take these measurements.
Asymmetry
With plagiocephaly, severity is determined on the degree of
asymmetry, in millimetres, of the baby’s head. The two
diagonals of the head are measured with calipers, from above
the corner of each eye, across the centre of the head to the
back. The smaller length is subtracted from the larger to
give the asymmetry.
The classifications in the UK are generally:
- Mild plagiocephaly - less than 6mm
- Moderate plagiocephaly - 6 to 12mm
- Severe plagiocephaly - over 12mm, but measurements of over
20mm are not uncommon
Cephalic ratio / cranial index
With brachycephaly and dolichocephaly, asymmetry is not a
factor unless there is a combination of brachycephaly with
plagiocephaly. Instead, the cephalic ratio (or cranial
index) is the measurement that determines the severity.
Cephalic ratio is the head width as a percentage of head
length, again measured using calipers.
An “ideal” head has a cephalic ratio of 78% and the
"normal" range is 73-83%.
Moderate brachycephaly – 83.1% to 87.9%
Severe brachycephaly – 88% and over, but measurements of
over 100% are not uncommon
Moderate dolichocephaly – 68.1% to 72.9%
Severe dolichocephaly – 68% and less
