Scaphocephaly

What is Scaphocephaly?

Scaphocephaly is a condition where the shape of the skull is unusually long and narrow due to an early fusion of a specific seam on the skull, known as the sagittal suture. This early fusion forms a bony ridge. This shape is often compared to a boat, hence the term “boat-shaped” head or also known as dolichocephaly. Scaphocephaly is the most common form of a condition called craniosynostosis.

It’s really important to identify and diagnose Scaphocephaly early on. If not, it can lead to abnormal growth of the part of the skull that houses the brain, thereby affecting the brain’s growth and development.

What Causes Scaphocephaly?

Scaphocephaly is caused when the sagittal suture, a connective tissue gap in the skull, closes too early. Normally, this closure starts around age 22 and majority of individuals fully complete this closure between the ages of 30 to 50. The closing of this suture too early results in a particular type of craniosynostosis, a condition where one or more of the sutures in a baby’s skull close earlier than normal. The exact reason for this early closure, especially in nonsyndromic craniosynostosis (craniosynostosis not associated with any other abnormal features), is still not fully understood. However, it usually happens by chance.

Several factors are believed to contribute to this condition. They include specific gene mutations, metabolic and blood disorders, exposure to certain harmful substances like valproic acid (a medication), maternal smoking, and advanced paternal age.

A combination of these external influences and genetic mutations are often involved in the development of this condition. Research has identified more than 100 mutations linked with nonsyndromic craniosynostosis. The most frequent and well-studied mutation involves the fibroblast growth factors (FGFR) genes. In cases of sagittal craniosynostosis specifically, the most common mutation is found in the SMAD6 gene. Other identified genes include TWIST1, TCF12, ERF, and MSX2. However, it’s worth noting that these mutations are only found in a few cases.

Risk Factors and Frequency for Scaphocephaly

Craniosynostosis, a birth defect that affects the formation of the skull, is seen in around 1 in every 200 to 2,500 babies when they’re born. This condition is most commonly diagnosed in children who are non-Hispanic white. The most common type of craniosynostosis is called “sagittal craniosynostosis”, representing around 53% to 60% of all cases.

• Sagittal craniosynostosis is three times more likely to occur in males, accounting for around 80% of the cases.
• The rate of craniosynostosis is lower amongst children of the Hispanic ethnicity and non-Hispanic black race.

Signs and Symptoms of Scaphocephaly

Parents often notice that their child’s head appears unusual or the shape seems to worsen as the child grows. These are potential signs of a condition called craniosynostosis. This condition typically comes to attention with the ongoing monitoring of the child’s development.

Medical professionals will thoroughly observe the child’s condition during a physical exam. They will often notice that the child’s head is elongated, and a hard ridge may be felt over the highest point on the head. Measurements of the head can reveal that the length from front to back is longer than expected while the width from side to side is shorter, giving the head a narrow and somewhat boat-shaped appearance.

Further observations may include bulging at the forehead and back of the head. Medical professionals calculate a number called the “cephalic index,” which is a ratio of the width to the length of the head, to measure the degree of this change. A healthy average is around 80-83, but in cases of scaphocephaly, a form of craniosynostosis, the index may be lower. However, there should be no noticeable changes to the base of the skull, the eye sockets, or the face unless the child has a syndrome that involves craniosynostosis.

In addition to the head shape, it’s also important to check for breathing difficulties. If the condition is severe, it can cause the baby’s head to unnaturally bend back when lying flat, which might lead to breathing problems. The child’s eye health should also be evaluated to monitor for a condition called papilledema, which is a warning sign of abnormally high pressure within the skull.

Testing for Scaphocephaly

When a doctor suspects that you might have a fused suture in the skull, the first step is often just a manual physical exam. This involves feeling for a hard bump along the line where the bones of your scalp come together (the sagittal suture).

If your doctor believes that this suture might be improperly fused, they will likely order imaging tests to confirm. These tests could involve x-ray pictures of your skull, an ultrasound (which uses sound waves to create pictures of the inside of your body), or a computed tomography (CT) scan. A CT scan is like an x-ray but provides more detailed images and can sometimes involve reconstructing a 3D image of your skull for extra clarity. However, this isn’t always needed. CT scans can also highlight any other abnormalities in the bone structure or show if there’s excessive fluid buildup in the brain (a condition known as hydrocephalus).

In some instances, magnetic resonance imaging (MRI) might also be ordered. This is a type of scan that uses powerful magnets and radio waves to produce detailed images of the inside of your body. An MRI might be necessary if the case is more complicated and detailed images of the brain are required. Importantly, an MRI doesn’t involve any radiation but instead uses strong magnetic fields and radio waves to create detailed pictures. This can be a better option for people who need to avoid radiation exposure, like those with the bone condition craniosynostosis.

In rare cases where a person has unusual metabolic disorders affecting their skeleton and is suspected to have craniosynostosis, it’s vital to have them examined early and follow up as necessary.

Treatment Options for Scaphocephaly

Sagittal craniosynostosis is a condition where the joints between the bones in a baby’s skull fuse together too early. This can cause an abnormal head shape, which might have psychological impacts on both the child and their parents. To prevent this, doctors usually recommend surgery. This surgery involves removing the fused joints in the skull. It’s best if this surgery happens within the first 3 to 6 months of the baby’s life, because if it’s done after 12 months old, more bone has to be removed and reshaped. Also, if the treatment is delayed, the skull can thicken and slow the growth of the brain. That’s why it’s important to act early to get the best results.

During the surgery, one of the key things the surgeon has to do is manage any bleeding. Before the procedure, the patient will typically receive antibiotics to avoid any infections. The goal of the surgery is to reshape the skull so that another operation won’t be necessary. Surgeons can perform this operation using either traditional (open) methods, or a method called endoscopy. Endoscopic surgery often results in less blood loss, but it typically requires the baby to wear a helmet for several months after surgery to help reshape the skull.

Endoscopic surgery involves placing the baby in a special position that lets the surgeon access the front and back of the skull. The surgeon makes two incisions, or cuts, along the middle of the skull. They then separate a protective layer called the dura from the skull, and remove the fused joints. After that, they use a medical instrument called an endoscope to move towards the back of the skull. Once the dura is freed, the surgeon uses medical scissors to make additional cuts and remove any remaining fused joints. This operation is often able to improve the shape of the skull without causing damage to the dura, which is important for future bone growth.

The traditional or ‘open’ surgery may be necessary for milder cases or for more severe ones where a full reshaping of the skull is needed. This method involves making a sawtooth-shaped flap in the scalp, then exposing and removing each fused joint one-by-one. With its removal, the skull often naturally widens. The pieces of removed joints are left floating above the dura. If necessary, the surgeon can add bone grafts (transplanted bone tissue) to fill any resulting gaps. Finally, the surgeon sews the flap back together. Depending on the case, this method might also require the removal and reshaping of the frontal or back part of the skull. After the operation, the baby will stay overnight in a pediatric intensive care unit for monitoring.

An alternative approach is the spring-assisted surgery. This method is similar to the traditional surgery, but it uses springs to assist in the skull expansion. This technique is associated with less blood loss and shorter surgery and hospitalization times. However, it requires a second surgery to remove the springs. Research shows that the endoscopic approach often results in shorter hospital stays, less blood loss, and fewer blood transfusions compared to the open approach.

What else can Scaphocephaly be?

When diagnosing non-syndromic craniosynostosis, doctors need to consider other potential causes. These might include:

• Hyperthyroidism
• Hypercalcemia
• Renal osteodystrophy
• Hypophosphatemia
• Vitamin D deficiency
• Sickle cell anemia
• Thalassemia
• Polycythemia vera
• Microcephaly
• Prematurity
• Shunted hydrocephalus
• Sly syndrome
• Morquio syndrome
• Hurler’s syndrome
• Beta-glucuronidase deficiency
• Mucopolysaccharidosis
• Mucolipidosis III
• X-linked hypophosphatemia
• 1-alpha hydroxylase deficiency
• Exposure to harmful substances in the womb (phenytoin, valproic acid, retinoic acid, aminopterin)
• Pseudohypoparathyroidism
• Osteopetrosis

In addition, it’s important to distinguish single suture craniosynostosis from syndromic craniosynostosis, which usually affects the coronal suture and leads to a condition called brachycephaly. Syndromic craniosynostosis might be due to any of these syndromes:

• Apert syndrome
• Crouzon syndrome
• Muenke syndrome
• Pfeiffer syndrome
• Saether Chotzen syndrome
• Craniofrontonasal syndrome
• Carpenter syndrome

What to expect with Scaphocephaly

After surgery, the head usually reshapes to a more typical round form. Both endoscopic and open procedures effectively correct skull deformities linked to sagittal craniosynostosis, a condition affecting the skull’s growth. A systematic review couldn’t find enough information to say that one treatment provided better cosmetic results than the other. The level of correction in strip craniectomy is less than in cranial vault reconstruction but doesn’t significantly affect the appearance. Some doctors suggest overcompensating during surgery to offset reduced post-surgery growth of the skull.

Long-term studies have found that patients with sagittal craniosynostosis, and other nonsyndromic craniosynostosis forms, can experience mild difficulties in cognitive, language, and motor skills during infancy and childhood. In one study, reading or spelling disabilities were seen in up to 50% of these patients. Around 39% suffered from cognitive and speech problems, but compared to other craniosynostosis types, those with sagittal craniosynostosis were less likely to have such issues.

Patients with this condition tend to fall within the standard intelligence range but have a higher rate of learning disabilities. They generally record a higher verbal IQ than performance IQ, indicating possible issues in achievement areas. One study found no increase in cognitive impairment. Although surgery for sagittal craniosynostosis may increase the risk of learning disorders, there isn’t enough evidence to compare different procedures’ impact on cognitive and neurological outcomes.

Possible Complications When Diagnosed with Scaphocephaly

Here are some complications that could possibly arise from the surgical procedure to correct craniosynostosis:

• Leaking of cerebrospinal fluid
• Tearing of the dura, a layer of the brain
• Excessive blood loss during operation
• Coagulopathy, a condition where the blood’s clotting mechanism is impaired
• Decreased activity
• Elevated body temperature
• Local infection at the wound site
• Abscess forming in the area just outside the dura
• Collection of blood beneath the skin
• Collection of blood in the area between the skull and the dura
• A vein filled with air bubbles
• Insufficient correction of the condition
• Need for additional surgery
• Wearing away of the scalp
• Ulcer forming on the scalp

Recovery from Scaphocephaly

When a child is admitted to the pediatric intensive care unit, they typically stay for about 24 hours. The main focus of the initial care provided by the nurses is to check on the child’s neurological status, which simply means they’re keeping an eye on the child’s brain functions. They also monitor the child’s fluid balance, electrolyte levels (minerals in the body that are needed for the body’s cells to function) and manage any discomfort they might be feeling. One of the measurements the nurses closely watch is the hematocrit level, which is the ratio of the volume of red cells to the total volume of blood. If the hematocrit level falls below a certain level, a blood transfusion can be given.

For pain management, pain relief medication like acetaminophen and ibuprofen is given to the child, and sometimes additional doses of morphine are given through an IV if the pain is severe. Antibiotics might also be given to the child to prevent infection following surgery.

The child’s condition is carefully monitored for signs of proper blood clotting (hemostasis) and any indications of infection. After surgery, swelling on the scalp can be uncomfortable, but this can be reduced by raising the head of the child’s bed. By the first or second day after the operation, the child is normally moved to the general pediatric floor. Any swelling on the face and scalp typically goes away within one to two weeks.

Photos are taken before and after surgery to check on how well the outcome is. Ideally, the child is followed up for at least five years to assess how well the reshaping of the skull is progressing. The pattern of reshaping and the child’s age will help the doctor determine when further surgery might be needed. In children who are older than one or two years, if there are cranial defects (issues with the skull) that are larger than 2 cm in diameter, procedures like using bone grafts or substitutes might be needed to fill these defects and avoid permanent issues.

Preventing Scaphocephaly

Being diagnosed and treated for craniosynostosis, a condition that affects the growth pattern of a baby’s skull, can significantly impact families. To better manage this situation, it’s essential for families to have a thorough understanding of the condition, treatment options, after-surgery care, and the likely outcome. To ensure this understanding, all family members, even the grandparents, have the opportunity to meet the surgical team. This meeting is a chance to ask questions and discuss any worries regarding the surgery, which affects the entire family.

In cases of craniosynostosis that aren’t associated with any other syndrome, particularly sagittal craniosynostosis which affects the main ‘suture’ or joint on the top of the skull, doctors may perform tests for a mutation in the SMAD6 gene. If this mutation is found, parents will be provided with genetic counseling for a better understanding. If there is no family history of craniosynostosis and no genetic mutations are found, the chance for the condition to recur in future children is about 5%.

Patients experiencing increased pressure in the skull due to craniosynostosis may not show typical symptoms of excessive fluid in the brain, also known as hydrocephalus. Instead, they might exhibit signs such as papilledema (swelling of the optic nerve), skull deformities, delayed development, or an inability to reach key developmental milestones at the typical age range.