Brachycephaly

What is Brachycephaly?

Brachycephaly, a term that comes from the Greek words for “short” and “head,” refers to a condition in babies where their skull is shorter than usual in relation to its width. This results in the back part of the baby’s skull, the cranium, being flattened and causing their head to look shorter from front to back. There are two types of brachycephaly: positional (not linked to craniosynostosis) and synostotic. Since 1992, more babies have been seen with positional skull deformities. This increase has been linked to recommendations from the American Association of Pediatrics for babies to sleep on their backs to prevent Sudden Infant Death Syndrome (SIDS). However, brachycephaly can also occur in infants due to craniosynostosis.

In order to understand the condition better, it’s crucial to know that a baby’s skull has two main functions: protecting the brain and allowing it to grow and develop. The top part of the skull, the cranial vault or calvaria, is made up of several bones that are separated by flexible joints known as cranial sutures. These sutures separate different sections of the skull. For instance, the sutures separate the two bones at the front of the skull, the two bones at the top and sides of the skull, and the single bone at the back of the skull from each other. The junction points, called fontanelles, close over time – the one at the front by the age of three years and the one at the back by three months old. Craniosynostosis is a condition where one or more of these sutures fuse together prematurely before the brain has fully grown and developed in infants.

What Causes Brachycephaly?

Positional or deformational brachycephaly happens when an infant’s skull changes shape due to external forces after birth. When a baby is born, the skull bones aren’t fully fused so that the brain can continue to grow. Because of this, the infant’s skull can be easily molded and is vulnerable to outside forces that might change its shape.

Often, when babies are put to sleep on their backs regularly, the back of their head or occipital bone can become flat. This results in positional or deformational brachycephaly. A related condition, deformational plagiocephaly, can develop if there is a flattening on one side of the occipital bone. Certain infants might display signs of brachycephaly at birth itself, which can be due to a long labor, abnormal position in the womb, multiple babies at once, low levels of amniotic fluid (oligohydramnios), or structural anomalies of the uterus.

The skull is made up of two parts: neurocranium, which protects the brain, and viscerocranium, which forms the facial bones. The neurocranium consists of a dome-like part called the calvaria and the base known as the chondrocranium. If the skull bones start to fuse prematurely, it can result in a condition called craniosynostosis. Abnormal early fusing of both coronal sutures – the joints between frontal and parietal bones – results in anterior brachycephaly, while premature fusing of only one coronal suture leads to anterior plagiocephaly.

Craniosynostosis could also be caused by genetic abnormalities that influence the growth factors in our body, which help in cell growth, migration, and the formation of normal bone structures. Some of these genetic abnormalities are FGFR-2 and FGFR-3, TWIST1, and EFNB1 gene mutations. These mutations can either show physical symptoms (syndromic) or not (non-syndromic). Syndromic conditions that include craniosynostosis are Crouzon syndrome, Apert syndrome, Pfeiffer syndrome, Saethre-Chotzen syndrome, Antley-Bixler syndrome, and Muenke syndrome.

Risk Factors and Frequency for Brachycephaly

Positional brachycephaly or plagiocephaly, a head-shape abnormality, affects between 20% and 50% of infants in the United States. About 20% of these cases can be noticed at birth, while 80% develop within the first three months of life. This condition generally occurs more frequently in male children. Interestingly, nearly 93% of baby patients with this condition also have some degree of torticollis, a condition often overlooked by doctors.

On the other hand, synostotic brachycephaly, a condition caused by bicoronal synostosis, is present in around 3% of non-syndromic synostoses, and it has a higher presence of around 0.5 in every 10,000 live births in syndromic synostosis. Lambdoid craniosynostosis is considered quite rare, making up 1% to 9% of craniosynostosis cases.

Signs and Symptoms of Brachycephaly

It’s crucial to distinguish between different types of irregularities in an infant’s head shape, including non-synostotic (like brachycephaly or plagiocephaly) and synostotic (such as bi-coronal or bi-lambdoid synostosis) abnormalities. This distinction is made through a thorough history taking and physical examination. Relevant questions include whether there’s a family history of abnormal head shapes, any exposure to harmful substances during pregnancy, when the irregularity was first noticed, past instances of restricted space for the baby’s head in the womb, and the birth history.

The physical examination involves checking the baby’s head size, feeling the joints in the skull for any unusual ridges, and checking the soft spots on the head (fontanelles) for signs of increased pressure inside the skull. It’s important to look at the baby’s head from different views – front, back, side, and above. Measuring tools can give valuable details about the head length, width, and certain distances across the head. A complete neurological examination should be done as well. Calculating ratios like the cephalic index (maximum head width to maximum length) and the cranial vault asymmetry index (percentage difference between measurements across the head diagonally) can also be helpful.

Different abnormalities have distinct characteristics. Positional brachycephaly, for instance, is marked by flattening on both sides of the back of the head, widening of the back of the skull, bulging at the sides of the skull, and a round face. In contrast, synostotic brachycephaly typically comes with ridges along the joints of the skull. In some abnormalities, certain features might appear displaced or differently shaped, like a towered forehead or shallower eye sockets. Particular signs like the Harlequin eye sign (one eyebrow positioned higher than the other) can be seen. It’s essential to determine if other abnormalities are present around the head or throughout the body, as they might indicate a related syndrome.

Positional plagiocephaly leads to a kind of parallelogram-shaped head. The head will be flat on one side at the back, with bulging on the same side at the front as well as at the back on the opposite side. The ear will be more towards the front, and the bone just behind the ear will look normal.

On the other hand, posterior plagiocephaly due to unilateral lambdoid craniosynostosis results in a trapezoid-shaped head. Similar to positional plagiocephaly, there’s flattening at the back of the head. But unlike positional plagiocephaly, there’s also bulging on the opposite side at the front and the side. The ear will be positioned more towards the back, and the bone behind the ear will be bulging and pointing downwards.

With bilateral lambdoid suture craniosynostosis, the presentation is similar to brachycephaly, and both ears will be positioned more towards the front and downwards.

The presentation of bi-coronal craniosynostosis manifests as a towered forehead, seemingly shallow eye sockets, and a shorter nasal bone.

Anterior plagiocephaly arises from unilateral coronal suture craniosynostosis and results in bulging on the opposite side of the forehead.

Testing for Brachycephaly

When a doctor suspects craniosynostosis, which is a condition where the joints between the bones of the baby’s skull close prematurely, they perform a physical examination. This is the most important part of the diagnosis process.

In many cases of positional plagiocephaly, which is flat head syndrome caused by external pressures on the head, the doctor does not typically need any special imaging tests to make a diagnosis. However, if there’s any doubt, imaging tests can be helpful.

On the other hand, if the doctor thinks the baby might have craniosynostosis, which involves premature fusion of the skull bones, then imaging tests are necessary. These tests include a skull x-ray or a specific type of scan known as a computed tomography (CT) scan. A CT scan can provide a 3-dimensional image of the baby’s head, making it easier to see any abnormalities.

Other imaging options might include an ultrasound, especially before the fontanelle (or the baby’s “soft spot”) has closed, or a magnetic resonance imaging (MRI) scan if there are concerns about other abnormalities within the brain, such as fluid build-up (hydrocephalus). The CT scans or X-rays can show signs of craniosynostosis, such as thickened sutures (the joints between the skull bones) or a hardened edge along the suture under investigation. In some cases, these sutures may not be visible on the images.

If the baby has other symptoms suggesting a genetic syndrome, tests may be performed to check for these conditions. A genetic syndrome is a health problem caused by one or more abnormalities in the genome, the complete set of human genes plus all the DNA in the human body.

Treatment Options for Brachycephaly

Positional plagiocephaly and brachycephaly are conditions that lead to misshapen heads in infants. These are typically managed without surgery. To prevent these conditions, pediatricians recommend several preventive measures like “tummy time” during infancy and alternating head position to one side or the other while the baby is sleeping, which is known as early repositioning. If the baby’s muscles in the neck are unbalanced (a condition known as torticollis), certain exercises would be advised. It is not necessary to perform surgery for these conditions, as they do not involve the abnormal fusion of the skull bones, a condition known as craniosynostosis.

Families should be reassured that correction can be achieved with simple measures. Other non-surgical treatments include massage therapy, physiotherapy (for torticollis), assistive devices, and helmet therapy. However, helmet therapy can be costly, requires regular visits to a healthcare specialist known as an orthotist every two weeks and can even lead to complications such as pressure sores, underneath-the-skin abscesses, and failure to correct the deformity. Therefore, focusing on prevention and active repositioning is generally the best approach.

For infants with skull shape abnormalities due to craniosynostosis, where certain bones in the skull fuse together too early, surgery is necessary. In this case, the timing of the surgery is very important. Infants showing signs of increased pressure inside the head need to be treated urgently. Typically, surgery for a common type of craniosynostosis known as bi-coronal synostosis is performed between 6 and 12 months of age. Another type, known as lambdoid synostosis, typically requires surgery between the 2nd and 6th months of life.

There are various strategies to treat this condition surgically, including cranial vault remodeling, spring-assisted cranioplasty, and endoscopic suturectomy. Typically, a helmet is fitted within a few days after endoscopic surgery and may be worn for up to a year after the procedure. Compared to other methods, endoscopic surgery offers benefits such as less discomfort to the patient, lesser blood loss, and shorter hospital stays. However, this technique is best used within the first 6 months of age when the bone is the most flexible.

In contrast, open surgical repair is usually performed between 4 to 12 months of age, and it generally involves making an incision in the skin of the head and reshaping the bones of the cranial vault, the upper part of the skull that protects the brain. The specific techniques employed will depend on the type of craniosynostosis. For instance, surgery for lambdoid craniosynostosis requires opening parts of the skull from both sides and reshaping the frontal and occipital bones, the bones at the front and back of the head. In cases of coronal craniosynostosis, a kind of remodeling of the front section of the cranial vault involving the eye sockets is used. This involves cutting into the front parts of the skull, creating a band-shaped piece of bone from the eye sockets, and then advancing the section in front of the skull.

What else can Brachycephaly be?

Infants with synostotic brachycephaly, which involves the fusion of certain skull joints, could potentially be showing signs of various syndromic conditions. To identify these conditions, a standardized physical examination is crucial. Some of the common syndromes included in the potential diagnosis are:

• Crouzon syndrome: This involves bicoronal synostosis that results in brachycephaly, bulging eyes, underdevelopment of the midface, an upturned nose and often includes a unique underbite. People with this syndrome usually have normal intelligence.
• Apert syndrome: This also involves bicoronal synostosis and the fusing together of the 2nd, 3rd, and 4th digits. Individuals may have cognitive impairments and an underdeveloped mid-face.
• Pfeiffer syndrome: This includes craniosynostosis, unusually wide and inwardly deviated thumbs and big toes, varying degrees of protruding eyes, and hearing problems. Different types of Pfeiffer syndrome have different characteristics, such as midface hypoplasia, high forehead and dental abnormalities, while some types may involve severe brain complications.
• Saethre-Chotzen syndrome: Also known as “acrocephalosyndactyly,” this involves craniosynostosis and potential fusion of specific digits. Other features include a low-set hairline and uneven face.
• Carpenter syndrome: This includes craniosynostosis, the fusion or addition of specific digits, a possible short stature, and potential congenital heart defects.
• Antley-Bixler syndrome: This includes craniosynostosis, bulging eyes, low-set ears, an underdeveloped mid-face, fusion of specific bones in the forearm, abnormally long fingers, and joint contractions.
• Muenke syndrome: This includes coronal craniosynostosis, fusion of the wrist bones, hearing problems, developmental delay, cone-shaped ends of long bones in children, and a high, narrow roof of the mouth.
• Beare-Stevenson cutis gyrata syndrome: Features include craniosynostosis, furrowed and wrinkled skin appearance with patches of skin discoloration, nasal obstruction at birth, pancreatic abnormalities, and underdeveloped or missing earlobes.
• Jackson-Weiss syndrome: This includes craniosynostosis, midfacial hypoplasia, wide big toes, and fusion or malformation of specific bones in the feet.

What to expect with Brachycephaly

Positional brachycephaly or plagiocephaly are common abnormalities in an infant’s head shape that are often noticed in routine health check-ups. These conditions occur when a baby’s soft skull becomes flattened in one area, due to repeated pressure on that particular spot. Simply reassuring parents and suggesting ways to adjust the child’s positioning usually solves the problem. Most babies show improvement as they grow and hit their developmental milestones.

However, if the condition doesn’t improve with these simple measures, the baby might need to use a special helmet for some time, which helps gently reshape their head. Also, in rare cases where the baby’s skull bones prematurely fuse (a condition called craniosynostosis), it’s crucial to seek expert opinion from a specialist team who deal with facial and skull conditions. This early intervention could prevent the need for more complex surgery later on.

Surgeries for fixing non-syndromic craniosynostosis, a type of the condition not associated with any other syndrome, have excellent cosmetic outcomes. Whether the approach is open (traditional) surgery or the less invasive endoscopic surgery, the chances of needing further procedures are low.

Possible Complications When Diagnosed with Brachycephaly

Positional brachycephaly, or a flat spot on the back of a baby’s head, is mostly a cosmetic issue and there’s limited evidence to suggest it may affect a baby’s brain development. However, if a baby has synostotic brachycephaly – a condition where the flat spot is caused by a fusion of the skull bones – it can restrict brain growth and raise the baby’s internal head pressure. This condition often increases head pressure in untreated older patients too. There have been suggestions that this form of brachycephaly might lead to cognitive and behavioral challenges due to increased pressure inside the skull, while other studies haven’t found a link. The reality is, the impact of surgery to correct craniosynostosis – a condition linked to synostotic brachycephaly – on a child’s future brain development is still up for debate.

Key Points:

• Positional brachycephaly primarily has cosmetic effects.
• There’s little evidence it affects brain development.
• Synostotic brachycephaly can restrict brain growth and raise internal head pressure.
• This condition can lead to increased head pressure in untreated older patients.
• There’s debate about possible link between this condition and cognitive/behavioral challenges.
• It’s still uncertain whether surgery for associated craniosynostosis affects future brain development.

Preventing Brachycephaly

If parents are worried about the shape of their baby’s head, it is recommended that they speak with a pediatrician as soon as possible. The pediatrician can then determine if the infant might have a condition called Craniosynostosis. This is a condition where the joints in the baby’s skull fuse too early, causing a misshaped head. If the pediatrician believes this might be the issue, they can arrange for the baby to be further examined by a team of specialists.

If the unusual head shape is the result of something called positional plagiocephaly instead, where the head shape changes due to the baby lying in the same position for long periods, then the pediatrician can provide advice and guidance to the parents on what to do next. In such cases, the doctor normally suggests changes in the baby’s positioning and some simple exercises to help correct the shape of the baby’s head.