What is Craniosynostosis?
Craniosynostosis (cray-nee-oh-sin-oh-sto-sis) is a rare condition found in around 3 in 10,000 live births. The condition affects how the bones in the skull grow and is translated from Greek; ‘cranio’ means head, and ‘synostosis’ means fusion. Treatment for craniosynostosis requires surgical treatment from a craniofacial unit and only then can a helmet be used to continue the treatment to correct any deformity. It is not exactly the same as flat head syndrome treatment but it is becoming a more accepted treatment regime.
Craniosynostosis is the premature fusion of one or more of the joints (sutures) between the bone plates that make up your baby’s skull. These sutures are normally flexible to allow for the natural birth process, and they remain open during growth to allow the brain to continue growth and develop naturally within the skull casing. Over time, as brain growth completes, the sutures close naturally to form a protective bone casing around the brain. In the case of a (cranio)synostosis, one or more of these sutures stick together prematurely causing the head to develop in an unusual shape, as the skull is unable to grow properly.
This condition can be confused with plagiocephaly and other variants of flat head syndrome as they all result in a skull deformation. To learn more about the difference between plagiocephaly and craniosynostosis, please read our previous post. At Technology in Motion, we see approximately 1 in 100 infants with undiagnosed synostosis.
What Causes Craniosynostosis?
Craniosynostosis causes are, for the most part, unknown as the condition is so rare. However, the condition can be related to particular genetic disorders, which is why craniosynostosis is divided into two types based on this factor:
1. Nonsyndromic craniosynostosis
This is the most common type of craniosynostosis and the cause of the condition is unknown. However, doctors and medical scientists believe that genetics and environmental factors may have an effect on how the sutures in the skull develop in utero.
2. Syndromic craniosynostosis.
This form of craniosynostosis means the skull fuses too early due to particular types of genetic syndromes, such as:
- Pfeiffer syndrome
- Crouzon syndrome
- Apert syndrome
- Carpenter syndrome
- Saethre-Chotzen syndrome
To read a more in-depth feature on the potential causes of craniosynostosis, featuring medical research references, please read our relevant article.
Which Sutures are Involved in Craniosynostosis?
The skull can be seen as two parts; the lower part called the cranial base supports the brain and has openings for the nerves and blood vessels. The upper part, called the cranial vault, protects the brain. The cranial vault has four main bones over the brain and one at the back of the head. These bones are connected by flexible fibres known as sutures. The sutures allow your baby’s head to compress during the birth process and then remain flexible throughout childhood to allow the brain and the head to grow normally.
The majority of synostoses occur in one or more of the four sutures connecting the cranial vault:
1. The metopic suture at the middle front of the brow.
2. The coronal sutures left and right going over the head from in front of the rear to the centre top.
3. The sagittal suture, which runs front to back from the top centre to the mid-back of the head.
There are other sutures in the skull that can fuse before they should but synostoses in these sutures are very rare indeed.
If any of these four sutures close before they should, the head will not be able to grow as it should to allow brain growth and the head will grow with a deformity. If this is the case, the suture(s) must be operated on to allow the head to develop without deformity.
Types of Craniosynostosis
1. Sagittal Suture Synostosis:
The most common suture to be involved is the sagittal suture with approximately 1 in every 5000 births. It is more common in boys, with a 3:1 male-female ratio.
Sagittal synostosis is the premature closure of the sagittal suture. If this suture is closed, the head can’t grow in width, resulting in a long thin head shape, with an overdeveloped brow. This shape is called scaphocephaly.
2. Metopic Suture Synostosis:
The next most common type of synostosis is the metopic suture, located at the front of the skull, centrally on the brow. If this suture is prematurely fused the head can’t grow in width at the brow and the resulting shape is called trigonocephaly (triangle shape).
3. Coronal Suture Synostosis:
Another common suture to prematurely fuse is the coronal suture on one side. This is called unicoronal synostosis, which severely affects the face.
The bridge of the nose is pulled to the side of the synostosis and the eye is ‘pulled’ up and out on the same side. Also, the ear on the affected side is pulled forward towards the synostosis. Furthermore, there is usually a flattening at the front and the back of the head on the same side as the synostosis.
This is most easily seen from a scan of the head shape (you can just see the tip of the nose at the top of the image).
These are the three most common types of synostosis, but there are other types, with some specifically associated with genetic syndromes, that require complex case management and are usually picked up early in life.
Craniosynostosis symptoms can include:
- Unevenly shaped skull
- Missing or an irregularly shaped fontanelle (soft spot) on the baby’s skull
- A hard ridge developing along the suture
- Distinctively slower head growth in comparison with the body
These signs of craniosynostosis are usually visible from birth or in the first few months. There are other craniosynostosis symptoms that can also come to light, based on the type of craniosynostosis each baby has, such as:
- Deformation of the eye sockets
- Ear position becoming displaced
- Specific developmental delay
More information on spotting craniosynostosis can be found in our article which answers the question, how is craniosynostosis diagnosed?
How to Diagnose Craniosynostosis
Craniosynostosis diagnosis involves a paediatrician, neurosurgeon or relevant specialist examining a baby’s head, and each process will be different dependant on the suspected type of craniosynostosis a baby has. The craniosynostosis diagnosis may include the following process depending on these relevant factors:
1. Initial examination
A physical examination where the doctor will feel and look for deformities in the baby’s skull and face.
2. Imaging test
This involves taking an x-ray, CT (computerized tomography) scan or possibly a cranial ultrasound which shows the doctor if there are any sutures that have fused in the baby’s skull. If there is a fusion, this should be apparent in the imaging.
3. Genetic test
A genetic test will only need to take place if the specialist detects syndromic craniosynostosis and needs to diagnose the syndrome.
The only form of treatment to correct craniosynostosis is surgery. The main aim of surgery is to ensure that the brain can grow normally without any increase in pressure on the developing brain. The type of surgery used, will also determine the extent of correction of any irregular head shape whilst also taking any pressure off the brain. Ideally, craniosynostosis surgery should be undertaken before the baby is 12 months old.
There are two types of surgery available to release each of these synostoses. The type recommended will be based on several factors including the age of the baby, which sutures are affected and the type of craniosynostosis the baby has. For more information on finding the right treatment for craniosynostosis, please read our previous post.
The two different types of craniosynostosis operation are outlined in details below.
1. Total Cranial Vault Reshaping
This is the more traditional surgery which involves exposing the skull and removing the suture and the bone area which has been deformed. The bone is then remodelled and reattached to the head to allow growth, now with no restriction.
Surgery times can vary depending on the type and severity of the suture and the age of the baby, but 8.5 to 9 hours is the usual duration of traditional surgery.
This type of surgery remodels the head shape during the operation, and there is usually no need to use any remodelling helmet afterwards.
2. Endoscopic Strip Craniectomy with a Remoulding Helmet
The surgeon uses an endoscope, a small camera which provides visibility of the operation area in a less invasive fashion. Endoscopic tools are used to release and remove the fused suture and to position openings where required to relieve pressure and to allow the head shape to remodel.
This type of operation takes about 5 hours, but the bones are not remodelled in theatre.
Postoperatively the baby wears a helmet up to the age of 18 months to allow the head to grow back into shape within the moulding helmet such as a TiMbandAir or TiMband. The helmet is custom-fitted to the skull and is designed to do two things:
1. First, it provides control in the areas where growth is not desired.
2. Secondly, the helmet has space to allow the bones of the skull to move and develop in the previously fixed areas, as the brain now continues to grow and develop naturally.
Is endoscopic surgery available in the UK?
Where it is clinically appropriate, some UK hospital craniofacial departments are now providing endoscopic surgery. After surgery, these babies are being provided with helmets, usually at the parents own cost.
Endoscopic surgery has been available since the early 2,000’s, having been developed as a treatment regime in the USA and gradually being taken up by surgeons around the world as training became available.
There are some UK surgeons who offer endoscopic surgery, but at the time of writing the Health Service will not fund the ongoing helmet treatment and the parents must do this themselves. The NHS Trust usually authorises this NHS/Private type of service with the parents before going ahead.
Craniosynostosis Risk Factors
Craniosynostosis complications can occur if the condition isn’t treated and depending on the type of craniosynostosis, these can include:
- Baby’s head shape remaining permanently abnormal
- Increased pressure in the skull leading to impairment of vision and brain development
- Impaired motor skills
- Cognitive decline
Some of these complications may be unnoticed for a period of time but may show themselves more clearly as the child grows and develops. You can read our summary on the 2012 research investigating the behavioural, cognitive and neurological impairments associated with craniosynostosis, on our blog.
Craniosynostosis Post-Surgery Treatment
Technology in Motion offers craniosynostosis treatment for those infants who have undergone endoscopic strip craniectomy or craniotomy, using a cranial remoulding method. A post-op craniosynostosis helmet is essential for allowing the head to recover and grow back to a regular shape as without it the head could remain in the deformed shape.
We and our clinical manufacturing partners in the Czech Republic have extensive experience in treating infants post-operatively using a craniosynostosis helmet and we greatly appreciate this collaboration. This international team approach offers substantial benefit to our clinicians and their patients.
How Does a Post-Surgery Craniosynostosis Helmet Work?
In the same way that a plagiocephaly or flat head syndrome helmet works, a craniosynostosis helmet is bespoke and designed to fit your baby’s head exactly. Using a photographic scan of the baby’s head, the custom made helmet helps to correct the position and formation of the skull so that it develops into a more normal shape. The helmet doesn’t restrict growth, it simply creates the space and direction that the head needs to grow into in order for the head shape to normalise.
You can learn more about helmet therapy as an advanced cranial remoulding treatment, including how they work and what they’re made from, on our dedicated helmet therapy page.
If you have any questions regarding craniosynostosis post-surgery treatment, then we would love to hear from you. Simply call us on 0330 100 1800 (local rate) for more information or to book a free consultation.
We’ve also compiled a list of frequently asked questions which will help you understand more about plagiocephaly and other variants of flat head syndrome, that may have interested you when mentioned above.