Plagiocephaly

What is Plagiocephaly?

Plagiocephaly is a term that originates from the Greek words ‘plagios’ (meaning oblique or slanted) and ‘kephale’ (meaning head). Simply put, plagiocephaly is when there’s an uneven shape of the head due to one-sided flattening. It is sometimes referred to as “flathead”. There are two main types of plagiocephaly: synostotic and deformational.

The International Classification of Diseases (a list that sorts diseases based on their symptoms) describes ‘isolated synostotic plagiocephaly’ as a condition not connected to any other syndrome which leads to an imbalanced head shape and facial appearance. This happens due to the early fusing of one coronal (front) or lambdoid (back) seam in the skull. ‘Anterior plagiocephaly’ refers to when this early fusing happens to the coronal seam, making the front part of the head uneven. If the lambdoid seam fuses early, it leads to ‘synostotic posterior plagiocephaly’, causing the back part of the head to be uneven.

On the other hand, ‘deformational plagiocephaly’ is a condition where external factors either before a baby is born (intrauterine) or after they’re born (postnatal) cause the head to become unevenly shaped. This type of plagiocephaly is also termed as ‘positional plagiocephaly’.

What Causes Plagiocephaly?

Nonsyndromic craniosynostosis is a condition which affects the skull, resulting in an abnormal shape. This is due to the early closure of the ‘sutures’ (joints between the bones in an infant’s skull). Most cases of this condition (over 95%) occur randomly and only 8-15% of patients with a specific type, coronal synostosis, have a family history of the condition. Meanwhile, in lambdoid synostosis, a different type, the chances of a family history is between 0% and 6%. The closure of the coronal suture typically begins around 24 years of age, whereas the lambdoid closure starts at around 26.

Certain forces during pregnancy or after birth can also influence the skull’s shape. For example, an unusual positioning of the fetus, abnormal shape of the uterus, or pressure on the baby’s head during a multiple pregnancy can affect its shape. After birth, the position that a baby’s head regularly rests in can also have an impact.

The cause of craniosynostosis often involves several factors, such as bone abnormalities, genetic changes, and environmental influences. Certain metabolic conditions (like low phosphate levels in the blood, rickets, overactive thyroid), premature birth, low birth weight, exposure to substances that can cause birth defects, and certain medications can also potentially play a role. In mice experiments, pressure on the fetal head was shown to increase certain growth factors, leading to this type of synostosis.

Certain genetic changes associated with one-sided coronal synostosis have been identified, notably involving the genes TWIST, FGFR2, and FGFR3.

There’s also a link between the shift to recommended sleeping positions for infants and an increase in deformational plagiocephaly, a condition where the back of a baby’s head becomes flat. This trend started in 1992 with the ‘Back to Sleep’ campaign, which advised that infants sleep on their backs to prevent sudden infant death syndrome. Risk factors for deformational plagiocephaly include assisted delivery (with forceps or vacuum), being a first-born child or male, sleeping in the supine position, limited neck rotation, low level of activity, and lack of ‘tummy time’ (the duration a baby spends awake and on their tummy). This condition is often associated with congenital muscular torticollis where, due to the persistent favorite head and neck position, a part of the head may flatten.

Risk Factors and Frequency for Plagiocephaly

Anterior plagiocephaly, a formation issue with a baby’s skull, occurs in about 1 out of 10,000 live births and 13-16% of babies with a condition called craniosynostosis. Unilateral coronal craniosynostosis, another skull issue, is 4 to 7 times more common than the bilateral type. For every two females born with this condition, there is one male. A rare type called unilateral lambdoid synostosis represents 1 to 5% of craniosynostosis cases and occurs approximately once in every 33,000 births.

Deformational plagiocephaly, a skull deformity in infants, affects 15 to 20% of babies. Some research even suggests up to 46.6% of babies have it. It’s slightly more common in males and typically diagnosed before four months. Before 1992, this condition affected one in 300 babies. However, after the “Back to Sleep” campaign, which encourages parents to put their babies to sleep on their back for safety, the rate of deformational plagiocephaly has increased 400% to 600%.

Craniosynostosis can also be triggered by systemic diseases like rickets and hypothyroidism. It may be seen in newborns with a small head size (microcephaly) and those who’ve had a shunt, a tube, placed to relieve pressure from excess fluid in the brain known as hydrocephalus.

Signs and Symptoms of Plagiocephaly

Anterior plagiocephaly, a condition that affects the shape of a baby’s head, leads to a flat forehead and a high supraorbital margin. The forehead may also jut forward on the side that’s not affected, and the nasal septum could deviate towards the unaltered side. Furthermore, there is a higher chance of particular eye conditions due to muscle dysfunction, and the jaw might be misaligned, altering the bite. A noticeable hard ridge can often be felt along the fused suture – the permanent joint area. In posterior plagiocephaly, the forehead and back of the head are prominent on the opposite side. The affected ear and mastoid, a bone located behind the ear, appear displaced downwards. A top-down view of the skull reveals a trapezoid shape.

Making a distinction between deformational plagiocephaly and posterior plagiocephaly can be difficult. Deformational plagiocephaly is typically more prevalent and develops a few weeks after birth, whereas lambdoid synostosis is present from birth. A child might favor a specific sleeping position in deformational plagiocephaly. The hard ridge along the suture and a protruding mastoid bone are indicative of lambdoid synostosis. Frontal bossing, a protruding forehead, is observed on the same side in deformational plagiocephaly but on the opposite side in lambdoid synostosis. There is a bulge in the back of the head on the opposite side in deformational plagiocephaly. Depending on the condition, the affected ear appears either displaced forward (deformational plagiocephaly) or backward (lambdoid synostosis). However, bear in mind that the ear position isn’t a fully reliable way to differentiate these conditions. The skull shape resembles a parallelogram in deformational plagiocephaly and a trapezoid in lambdoid synostosis.

About 15 to 20% of children with either coronal or lambdoid synostosis can experience increases in intracranial pressure. However, signs such as headaches, vomiting, altered consciousness, and a bulging fontanelle might not be present in every patient. The most reliable sign is papilledema – swelling in the optic nerve due to high pressure in the brain. Chronic high intracranial pressure can lead to vision loss from optic nerve damage and below-average intelligence.

Testing for Plagiocephaly

Craniosynostosis, the premature fusion of the joints between the skull bones, can be primarily assessed with imaging tests. The go-to option for this is a type of scan called a computed tomographic (CT) scan, reconstructed in three-dimensional (3D) form. This advanced CT scan allows doctors to clearly see all parts of the skull, including the skull base, while keeping radiation exposure reasonably low. When a fusion occurs prematurely, it stops the normal growth of the skull in one direction, causing the skull to overgrow in other directions. The CT scan helps to identify these changes by capturing images of the hardening around the fused joints, bone bridging, or the disappearance of the joint or “suture”.

In a condition called deformational plagiocephaly, which usually results from external factors and not premature suture fusion, the CT scan would show an open lambdoid suture, a part of the skull at the back. This condition typically doesn’t cause significant distortions in the anteroposterior axis, the line running from the front to the back of the skull.

In other forms of craniosynostosis, additional changes can be seen. For example, in unilateral coronal synostosis or fusion of the frontal suture, CT findings could indicate a shallow side of the front part of the skull, a raised roof and side wall of the eye socket on the same side, and a bulging forehead on the opposite side. Similarly, unilateral lambdoid synostosis, or fusion of the back suture on one side, could show flattening on the affected side but bulging elsewhere, a smaller back of the skull, and a tilted base of the skull. Special analysis of the skull can clarify these conditions better and differentiate between them.

Lambdoid synostosis can sometimes lead to a herniation, or abnormal protrusion, of the lower part of the brain into the foramen magnum, the large hole at the base of the skull. This condition is known as Chiari malformation. It can also be associated with hydrocephalus, the accumulation of fluid in the brain, and syringomyelia, the development of a fluid-filled cyst in the spinal cord. These conditions are easier to identify with brain magnetic resonance imaging (MRI). However, an MRI doesn’t show the sutures very well. A specific type of MRI, known as “Black Bone” MRI, can reveal an open suture, which appears as a bright signal, but won’t be visible if the suture is closed.

Besides scans, measurements taken manually with calipers can also help evaluate deformational plagiocephaly. These measurements, known as anthropometric measurements, can help determine the severity of the condition. For example, a key measurement to evaluate asymmetry is the difference in the cross diagonal lengths of the skull. A difference of up to 12 mm is defined as mild to moderate asymmetry, whereas anything over 12 mm indicates severe asymmetry. Another indicator used is the cranial vault asymmetry index, calculated using these measurements, with a value greater than 3.5 indicating severe asymmetry.

Treatment Options for Plagiocephaly

For children with deformational plagiocephly (a condition where the head has an abnormal shape due to pressure in the womb or from sleeping in the same position), or mild unilateral synostosis (a condition where the bones in the skull prematurely fuse), a non-surgical approach is usually most appropriate. Before this decision is made, a thorough medical examination and diagnosis should take place to ensure that it is safe.

The non-surgical treatment for deformational plagiocephaly involved adjustments to sleep positions, counter positioning (turning the baby’s head into different positions), physiotherapy for a condition known as torticollis (a tightened or shortened neck muscle), and tummy time. A specially designed helmet may also be recommended for babies who don’t show improvement with these techniques.

The use of helmets for deformational plagiocephaly was introduced in 1979. The helmet serves as a molding device that helps to reshape the baby’s head. Modern helmets are made to fit each child individually. The best age for helmet therapy is when the baby is 5-6 months old, as it tends not to be effective after 18 months. Some potential side effects of helmet therapy include skin irritation and pressure sores. It is worth noting that there isn’t strong evidence to support the use of helmets for deformational plagiocephaly, but they may be recommended for severe cases.

Surgical treatment is typically reserved for a condition called nonsyndromic craniosynostosis, which can lead to abnormal head shape, high pressure inside the skull, and psychosocial problems. The goal of surgery is to increase the volume inside the skull for brain growth and correct the skull shape. Surgery normally includes removing the fused suture (joint between the skull bones) and remodeling any abnormalities. The best time for this surgery is between 6 and 12 months old, when brain and head development is most active.

Surgical options include open craniotomy, where a bone flap is removed and remodeled, or endoscopic suturectomy, where minimally invasive surgery occurs through a small incision. Some patients also may need a surgical procedure to treat torticollis. Surgery can often resolve a condition called papilledema, which causes swelling in the back of the eye and is common in patients with synostotic plagiocephaly.

While the bones of the skull are flexible and easily manipulated through endoscopic surgery before six months of age, open surgery is typically preferred after this time. Endoscopic surgery may cause less blood loss, shorter operation time, and faster recovery. However, after endoscopic procedures, the use of a remodeling helmet is often necessary. This type of surgery, combined with helmet therapy, has shown improvements in eye-related conditions in children with unilateral coronal synostosis.

What else can Plagiocephaly be?

In simple terms, doctors need to figure out if a baby’s plagiocephaly (an asymmetrically shaped head) is due to the baby’s position (deformational) or because of a premature fusion of certain bones in the skull (synostotic). There are two types to consider: Anterior plagiocephaly, which happens due to coronal synostosis (a type of bone fusion), and Posterior plagiocephaly, which could be due to either positioning or bone fusion.

Doctors look at certain clues to tell them which type it might be. Things like whether the abnormal skull shape was present at birth, what the baby’s favorite sleep position is, and whether the skull shape changes over time can all provide useful information. For example, craniosynostosis (bone fusion type) is present at birth while deformational plagiocephaly usually develops after the baby is born. If a baby often favors a certain sleep position, it might point to deformational plagiocephaly. On the other hand, if the abnormal skull shape worsens over time, it might be due to craniosynostosis. Position-based deformities have a tendency to improve as the baby gets older and gains more control of their head.

When it comes to the physical signs, if a baby has unilateral lambdoid synostosis (a type of craniosynostosis), there will be a thick ridge over the fused bone area. Other signs might include uneven growth on the opposite side of the skull and an uneven ear position. The shape of the head and these characteristics can be the opposite in cases of deformational plagiocephaly.

For example, a top view of the baby’s head in lambdoid synostosis will look like a trapezoid while in deformational plagiocephaly it looks more like a parallelogram. A type of 3D scanning (CT scan) can be used to confirm the diagnosis. In addition, babies with deformational plagiocephaly may often have a condition known as torticollis (a twisted neck). A brain condition known as Chiari malformation can be present in cases of lambdoid synostosis.

What to expect with Plagiocephaly

In the case of deformational plagiocephaly, which is a condition where a baby’s head becomes flat on one side, good results are often achieved through conservative treatments, such as physical therapy and positioning, especially when started early. The skull is malleable in infancy, meaning it can be reshaped easily. Physiotherapy can help improve a related condition known as congenital muscular torticollis, which is a neck muscle issue that can cause a tilted head in infants.

On the other hand, a condition named nonsyndromic single suture synostosis, which is a premature fusion of bones in the skull, can cause persistent problems with mental and neurological functions if left untreated. However, surgical intervention can improve motor and cognitive functions, particularly in severe cases. Over the long term, surgery often results in normal academic and social abilities in patients.

If a condition known as craniosynostosis, another form of premature skull bone fusion, isn’t treated or managed, it can lead to increased intracranial pressure (ICP), which is a rise in the pressure around the brain, and cognitive impairment or difficulty with thinking abilities.

Surgery to correct synostotic plagiocephaly, a type of plagiocephaly caused by premature fusion of the skull bones, significantly improves the shape of the skull and yields high satisfaction among parents.

Possible Complications When Diagnosed with Plagiocephaly

Deformational plagiocephaly, which is an irregularly shaped skull, can often be corrected by frequently changing the infant’s position. Nevertheless, if left untreated, it may result in cosmetic deformities. One-sided coronal plagiocephaly, if not properly managed, could potentially cause crossed eyes (strabismus), a type of eye condition that makes the eyes look in different directions (astigmatism), lazy eye (amblyopia), and misalignment of the lower jaw (mandible malalignment).

For synostotic plagiocephaly, a condition where the child’s skull bones fuse too early, surgical corrections typically have minimal and minor complications, and these do not result in lasting problems. There are, however, certain risks related to surgeries meant to treat isolated and syndromic skull deformities. Notably, patients with craniofacial syndromes might be more susceptible to complications. Also, endoscopic procedures, which involve the use of a thin tube with a light and camera attached to it, usually require fewer blood transfusions compared to open procedures.

Possible surgical complications:

• Excessive blood loss
• Entrance of air into the veins (venous air embolism)
• Abnormal blood clotting (consumption coagulopathy)
• Leakage of cerebrospinal fluid
• Tears in the outermost and toughest membrane of the brain and spinal cord (dural tears)
• High body temperature (hyperthermia)
• Decreased activity (hypoactivity)
• Infection of the surgical wound
• Abscess in the space between the skull and outer covering of the brain (epidural abscess)
• Ear infections
• Blood accumulation beneath the skin (subcutaneous hematoma)
• Blood accumulation in the space between the skull and outer covering of the brain (epidural hematoma)
• Remaining skull deformity (residual plagiocephaly)
• Need for additional surgery (reoperation)

Helmet therapy is another treatment method that may also have complications, but they are extremely rare.

Possible helmet therapy complications:

• Inadequate corrective changes
• Damage on the skin where the helmet is applied due to pressure
• Scalp erosion, ulcers, and temporary hair loss
• Dermatitis caused by contact allergies

Recovery from Plagiocephaly

After surgery, the child should be watched closely in the children’s intensive care unit, especially if they’ve had open surgery. Doctors will pay close attention to the volume of fluids in the body, hemoglobin and hematocrit levels (which are measures of the red blood cells in the blood), and the child’s heart health. Pain relief can be provided through a medication called paracetamol. Sedatives, which are medicines that calm or soothe, should not be given once the child’s breathing tube is removed. If the child’s condition is stable the next day, it usually wouldn’t be necessary to continue invasive monitoring, which involves using tools that go inside the body to measure health.

Preventing Plagiocephaly

Spotting and treating synostotic plagiocephaly (a condition where the baby’s skull grows in a distorted way) early on can prevent any cosmetic issues for children as they grow up.

The primary way to treat deformational plagiocephaly (another term for this condition) involves adjusting the baby’s positioning behaviors. This may include changes to how a baby is held or laid down, to correct the shape of their head. But in some situations, more steps might be needed, like helmet therapy. Helmet therapy involves the baby wearing a special helmet that gently molds the shape of their skull over time.

It is crucial that parents get educated about the correct positioning and the use of ‘tummy time’. ‘Tummy time’ is when a baby is placed on their stomach while awake and supervised. It is a good way to promote stronger neck and shoulder muscles. Intervention or treatment should start immediately once the condition is diagnosed.

Also, it’s important to know that deformational plagiocephaly does not cause any delays in a child’s development or affect their brain functions.