What is Sagittal Craniosynostosis?

When thinking about the bones that make up the skull, imagine that each bone is a piece of a puzzle. Sometimes, two of the pieces can be put together too early, making it difficult to finish the puzzle properly. Similarly, the bones in babies’ heads can come together too early, resulting in head shapes that are not normal. Craniosynostosis is the name of the medical condition that causes the sutures in a baby’s skull to fuse together too early.

Infant and adult heads have very important differences. Infants typically have thinner and less dense bones, as well as soft spots where the bones of the head are not yet joined. These differences allow a child’s head to be flexible and allow room for brain growth. If a baby’s skull sutures fuse too early, this can change the head’s shape, increase pressure on the brain, and possibly affect developing abilities such as speech, memory, and attention. Research has also shown that children with abnormally shaped heads may be seen as “different” by others, which might affect the child’s social interactions and self-esteem. Doctors can help by performing a surgery to separate the skull bones, creating more space for the brain to grow.

Sagittal craniosynostosis is the most common form of craniosynostosis. It occurs when the sagittal suture, which runs vertically in between the parietal bones of the skull, fuses too early in development. If the sagittal suture fuses, it can prevent the skull from growing in the right direction. As the brain grows, it causes the other sutures in the skull to move further away from each other than normal, forcing the baby’s head to grow long and narrow instead of wide and round (Figure 1). Sagittal craniosynostosis occurs in about 1 out of 5,000 births and is more common in boys than girls [1, 2].

How is Sagittal Craniosynostosis Treated?

There are two types of surgeries to fix sagittal craniosynostosis: Total cranial vault reconstruction (bigger surgery) and endoscopic suturectomy (smaller surgery). The bigger surgery has been used for many years to manage craniosynostosis. During the surgery, doctors make a zig-zag cut in the skin to uncover the skull bones (Figure 2A). Once uncovered, pieces of the skull are removed and rearranged to create a more normal head shape. This gives the brain enough space to grow properly. Unfortunately, the bigger surgery may cause a lot of blood loss, which can complicate the recovery process and lengthen hospital stays [3].

The smaller surgery is newer and less expensive, involving fewer cuts and openings in the skull (Figure 2B). It depends on the skull’s ability to naturally reform after surgery and is recommended for children under 4 months old. Research indicates that the smaller surgery is preferred at a younger age due to the bone being thinner and more malleable than at a later age [4]. To help visualize the operation, surgeons make small incisions in the scalp to remove the fused suture. Another key difference between the two surgeries is that after endoscopic suturectomy, doctors give the child a special helmet to wear, which helps protect the baby’s skull and directs the bones to grow properly. The smaller surgery has proven to be a good alternative that can fix the baby’s head shape, lower the risk of problems that may happen during surgery, and allow the child to recover faster.

Which is the Better Surgery?

Since the discovery of the smaller surgery, researchers and doctors have wondered which surgery has the best outcome for patients. A previous study in 2014 compared 13 patients who had the bigger surgery and 6 patients who had the smaller surgery [5]. The researchers determined that both procedures were equally successful in correcting head shapes.

In the current study, the results of a greater number of patients who received both procedures were documented. There were a total of 55 children (44 males and 11 females), each of which had sagittal craniosynostosis and surgeries performed at The Hospital for Sick Children in Toronto, Canada. Most of the children were around 10 months old. There were 37 children who underwent the total cranial vault reconstruction, while 18 underwent the endoscopic suturectomy. Most of the children who had the bigger surgery were 17 months old, while the majority who had the smaller surgery were under 4 months old. It is important to note that five patients out of the 55 needed additional surgery to correct their head shape.

To compare the outcomes of the surgeries, 3D photos of each child’s head were captured before and after surgery, using a machine called 3dMD (Figure 3). During the 3D photo taking, each child wore a head cap to ensure that their hair did not affect the quality of the image, giving a better view of their head shape. Each 3D photo was uploaded to an editing program on hospital computers to calculate the cranial index, a standard measurement representing an infant’s head shape. To calculate cranial index, the researchers used a ruler feature within the program to measure the length and width of the child’s head. The surgeons found that both types of surgeries could fix the head shape of each child, but the bigger surgery was slightly better in making the heads have more of a “normal” shape.

Summary: Why is this Important?

Sagittal craniosynostosis, a condition that occurs when the skull bones fuse too early, can make a child’s head look long and narrow. This can cause the child to feel very different from their friends and family, which is one of the reasons why it is important to help. Sagittal craniosynostosis can also cause a lot of pressure to build up in the brain, which can make it difficult for the brain to grow properly and may lead to a variety of problems like headaches, vision loss, speech difficulties, and even memory issues. Surgeons can use two main techniques to fix sagittal craniosynostosis: cranial vault reconstruction (a bigger surgery) and endoscopic suturectomy (a smaller surgery). Doctors, surgeons, and researchers compared results of both operations and found that both surgeries could fix the childrens’ head shapes to make them look more normal, ensuring that the brain could develop properly and that the children could all live healthy lives. Overall, further research is needed to compare the safety and effectiveness of each surgery. Perhaps, with advancements in the field of artificial intelligence, new technologies could be of great use in both the diagnosis of craniosynostosis and in determining which surgery offers the best outcomes.

Glossary

Craniosynostosis: ↑ A medical condition in which the bones of the skull come together too early, resulting in an abnormal head shape.

Suture: ↑ A joint connecting the bones of the skull. Sutures help the skull grow and change as the brain grows.

Fuse: ↑ The process by which the bones of the skull connect along the sutures.

Sagittal Suture: ↑ A joint connecting the parietal bones of the skull along the midline. It remains unfused for flexibility during childbirth and early brain growth in infants. It typically fuses during adulthood.

Total Cranial Vault Reconstruction: ↑ A surgical procedure to correct craniosynostosis by carefully removing, reshaping and reattaching the bones of the skull.

Endoscopic Suturectomy: ↑ A minimally invasive surgical procedure to correct craniosynostosis by using a small camera and specialized tools to open up the bones of the skull that have joined too early.

Cranial Index: ↑ A measurement used to describe the shape of the skull. It is calculated by dividing the width of the skull by the length of the skull and multiplying by 100.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.