Metopic (Trigonocephaly)

Metopic Craniosynostosis

Metopic craniosynostosis is the third most common type of single suture (non-syndromic) craniosynostosis and occurs when the metopic suture (the centre of the forehead) fuses prematurely before birth. The metopic suture separates the forehead bone in two from the anterior (front) fontanelle (soft spot) at the top of the forehead down to the top of the nose.

Metopic craniosynostosis can be associated with other conditions; the Craniofacial Surgeon will examine your child closely. The head shape which occurs because of metopic craniosynostosis is known as trigonocephaly which means triangle shape in Greek. 

How common is metopic craniosynostosis?

It is the third most common type of premature suture fusion affecting approximately 1 in every 15,000 births with a 3:1 male: female ratio which means that it is 3 times more common in boys.

What causes metopic craniosynostosis? 

The cause of metopic craniosynostosis is not yet known. Metopic craniosynostosis seems to affect more males than females but we are not yet sure why this is the case. There may be a genetic basis to the condition as it seems to be passed on from parent to child in a small number of families and in approximately 5% of patients, we may be able to identify the gene responsible. When some children are born with metopic craniosynostosis a known syndrome (collection of symptoms) can be identified.  More research is needed to identify the cause of metopic craniosynostosis which is increasing throughout the world.

What are the symptoms of metopic craniosynostosis?

Children with metopic craniosynostosis rarely have symptoms, with only the appearance of their forehead being obvious. A small percentage may also have hypotonia of their body (low muscle tone) and or developmental delay and behavioural problems, but this is rare and only slightly higher to be average population of children without craniosynostosis. While others may also have a speech and language delay where they tend to start to speak later than other children, this usually improves with from a speech and language therapist.

Raised intracranial pressure (ICP) seems to develop in approximately 5-10% of children when they are between 3 and 5 years of age. Raised intracranial pressure means the pressure inside the skull around the brain increases, which can cause pressure on the brain itself. If your child reports having headaches and are otherwise well with no other signs of an infection such as temperature, sore throat or ears or has a cough it is important to discuss this with a member of the craniofacial team as it may be a sign of raised intracranial pressure. 

We are not sure why raised intracranial pressure happens, but it can occur in both children who have had surgery to correct their head shape as well as in those who have not had surgery. 

What does metopic craniosynostosis look like?

The main sign of metopic craniosynostosis is a bony ridge over the prematurely fused metopic suture which gives your child a very pointed forehead. This prominent bony ridge extends from the ‘soft spot’ to the top of their nose. When looked at the head from above your child’s head shape will look like a triangle, pointed at the front and wider at the back of the head. Metopic craniosynostosis will also cause the eyes to be spaced closely together (hypotelorism) with some up slanting of the outer corners.

Also, children will often look as if their eyes are closer together and their eyebrows and forehead bone will be slanted backwards towards their ears.

 

A child with Metopic Craniosynostosis

Does my child need an x-ray?

We do not recommend x-rays to diagnose metopic craniosynostosis. The Craniofacial Surgeon and Neurosurgeon will make a diagnosis with careful assessment of your child’s skull. However, a CT-Scan with 3D reconstruction (3D CT scan) may be used to:

  • Verify the diagnosis of metopic craniosynostosis
  • Assess brain growth.
  • Evaluate if there is evidence of raised intracranial pressure
  • Assist in surgical planning 

3D CT scan of Metopic Craniosynostosis 

What happens in the craniofacial clinic?

You and your child will meet the Craniofacial Surgeon, Neurosurgeon, Craniofacial Nurse Specialist and Craniofacial Coordinator. The team will ask you about the pregnancy and your child’s medical /surgical history to date.  The Craniofacial team will confirm if your child has metopic craniosynostosis and discuss the options available to you. Your child will be referred to an Ophthalmologist (Eye Specialist) and a 3D CT scan may also be arranged. Once these assessments have taken place you will once again meet with the team at the craniofacial clinic where they will discuss any further questions you may have and the options for surgery to correct your child’s head shape. If your child has other medical conditions, your craniofacial consultant may decide to delay surgery until some of these problems are treated, this is to ensure your child is fit and well for surgery. Your expectations and conservative management (no surgery) will also be discussed at this visit. 

Your child should be assessed by an Ophthalmologist (Eye Specialist) to monitor for signs of raised intracranial pressure as this can happen in 14% of children with metopic craniosynostosis, especially when they are between 3 and 5 years of age. 

Once a decision for surgery has been made the Craniofacial Nurse Specialist will meet you in clinic to discuss the pre-operative (before surgery) planning including any further assessments or blood tests which must be completed. The Craniofacial Nurse Specialist will also discuss your child’s admission to hospital before surgery including preparation for surgery, expected length of stay in hospital and your child’s expected post-operative (after surgery) recovery course including managing their pain and care of their wound (scar) and the follow up appointments you will need to bring your child to after surgery. 

The Craniofacial Coordinator will liaise with all services both inside and outside of Children’s Health Ireland (CHI) at Temple Street to ensure that your child’s entire pre-operative plan is completed before surgery. The Craniofacial Coordinator will also be able to help you connect with other families who have recently gone through similar circumstances and surgery after their child was diagnosed with metopic craniosynostosis. The Craniofacial Coordinator will also give you the information about your child’s date of surgery.

Will my child need surgery?

The decision for surgery is based on severity of the craniosynostosis, the findings of the Craniofacial team with input from other teams where necessary and parental involvement. All families are offered the option of surgical management and treatment for their child’s head shape. For the more severe cases surgery to correct your child’s head shape is almost always necessary. For mild to moderate cases surgical management and treatment is offered. For the cases that are considered mild often conservative (no treatment) management with follow up as per our protocol is indicated. 

https://www.craniofacial.ie/wp-content/uploads/2020/02/NPCC-Care-Pathway-Metopic-2020.pdf

The team is always available should families wish to discuss surgery in the future if their child’s head shape becomes a problem for their child particularly from a psychological and or social perspective. It is important that families understand the only treatment to change your child’s head shape to a normal head shape is with surgery. 

What will my child’s surgery involve?

There is a close relationship between the growth of the skull and facial growth. Children with abnormal skull growth may have abnormal facial growth. Since the moulding and shape of the skull is directly dependent on the growth of the brain the best appearance changing results are obtained with early surgery. Surgery for craniosynostosis starts with the Craniofacial Surgeon making a cut in the skin across the top of your child’s head from ear to ear. This cut is shaped like a zigzag which makes it easier for your child’s hair to grow over it after surgery. The Craniofacial Surgeon will decide which parts of the skull bone need to be removed and reshaped (reconstructed) to give your child a normal head shape. Once all the bones are in place the Craniofacial Surgeon will stitch your child’s skin together.  

Surgical correction of metopic craniosynostosis involves a procedure called a Fronto-Orbital Advancement / Anterior Cranial Vault Remodelling (FOA/ACVR) generally; this surgery is performed when your child is between 12 and 18 months of age and is healthy and strong. It is during this time frame that the bones of the skull are thick enough and yet still malleable (pliable) to reconstruct. This surgery involves the removal of the frontal bones (forehead) and of the supra orbital rims (eyebrow bones) and the fused metopic suture. Once the bones are reconstructed the forehead and eyebrow bones are brought forward to allow the brain to grow. 

The skull bones are held in place with plates and screws (usually bio-resorbable ones which gradually dissolve between 12 and 18 months after surgery). Usually, there is not enough bone to reconstruct the entire skull and several “soft spots” or defects will remain. These will heal spontaneously over time, up to 24 months after surgery the brain is still growing rapidly, and any soft spots or defects left after the reconstruction will be filled in naturally by new bone being laid down. The surgery takes about 5 hours from start to finish, this includes putting your child to sleep and waking your child up. Your child will stay in hospital for approximately 4 to 5 days following surgery.  

 

A child pre and post Metopic Craniosynostosis Correction

Following surgery, infants and children generally stay in St Gabriel’s ward.  Before going home, the Craniofacial Nurse Specialist will discuss your child’s discharge and home care with you. https://www.craniofacial.ie/wp-content/uploads/2018/08/3.Following-Craniofacial-Surgery.pdf