Craniosynostosis (single suture) factsheet

Introduction

Craniosynostosis is a condition where the sutures between the bones in an infant's skull close prematurely. Sutures are fibrous bands of tissue that connect the individual bones of the skull.

If they close prematurely it can lead to abnormal skull growth and shape. This puts pressure on the brain, resulting in developmental delay and raised intracranial pressure.

The types of craniosynostosis are based on how many bones are fused together. It can present as an isolated condition or with a genetic condition or syndrome. Single suture craniosynostosis is the most common type and is explained in this factsheet.

Signs and symptoms

Here's what to look out for in the types of single suture synostosis (from most common to least common):

Sagittal

The sagittal suture runs from the fontanel (soft spot) at the front of the head to the back. Premature fusion of this suture leads to a long, narrow skull shape, called “scaphocephaly”. This is the most common type of single suture craniosynostosis.

Metopic

The metopic suture runs from the top of the head to the nose. Early closure can cause a triangular-shaped forehead, giving the appearance of a pointed skull with eyes close together. This is called “trigonocephaly”.

It is not to be confused with metopic ridging which creates a temporary ridge down the centre of the forehead.

Unicoronal

The coronal sutures run from ear to ear on either side of the skull. If one half of the coronal suture is fused, it results in an asymmetrical forehead with a bulge on one side and flattening of the other. On the affected side, the eyebrow is lifted and the nose is deviated.

Lambdoid

The lambdoid sutures are near the back of an infant's skull. Fusion in this area can lead to flattening or asymmetry of the back of the head. It needs to be differentiated from positional plagiocephaly, which happens when a baby sleeps with the head turned to the same side during first months of life.

Diagnosis

Sometimes, craniosynostosis can be diagnosed with an office examination alone. Imaging will be used to more closely examine the cranial sutures and confirm the diagnosis.

Physical exam: Your doctor feels your baby's head for features such as suture ridges and looks for facial differences such as unbalanced features.
Imaging studies: A CT scan or MRI of your baby's skull can show whether any sutures have fused. Cranial ultrasound imaging may be used. Fused sutures can be identified by their absence — because they are unseen once fused — or by a ridging of the suture line.
Genetic testing: If your doctor suspects an underlying genetic syndrome, genetic testing may help identify the syndrome.

Treatment

There are surgical options for children with single suture craniosynostosis.

The type of surgery recommended will depend on the types of craniosynostosis and child’s age.

Surgery is performed in babies with single suture craniosynostosis mainly for appearance and occasionally to deal with elevated pressure inside the head.

Strip craniectomy

Strip craniectomy involves the removal of a strip of bone from the fused suture, allowing the brain to grow more freely. The surgery usually takes less than an hour and children are discharged home the following day. Helmet therapy is used after the surgery, see details in 'Management' below.

This approach can be used for all types of craniosynostosis involving one suture. It is most effective when performed early in infancy, between 2.5 – 4 months of age.

Advantages

less invasive compared to other procedures
only one or two small scars are used to remove the strip of fused bone
helmet therapy (see 'Management' section below ) helps reshape the skull
blood loss and risk of blood transfusion minimised
high success rate, avoiding larger, more invasive types of surgical correction.

Complications:

incomplete correction
discomfort during helmet therapy, helmet worn 23 hours a day until the child is over 9 months (see 'Management' below)
risk of infection
need for additional interventions as the child grows.

Fronto Orbital Advancement (FOA) surgery

FOA involves removing the forehead and orbit (the space within the skull that contains the eye) bones, reshaping them and then replacing them onto the skull using dissolving plates and screws.

It is a routine but major craniofacial procedure. The surgery takes a few hours and is performed by plastic surgeons and neurosurgeons. Children remain in hospital for around 3 to 5 days afterwards.

FOA is used to treat types of craniosynostosis of the front of the skull, where the forehead needs to be reshaped or repositioned, such as metopic craniosynostosis, unicoronal synostosis or bicoronal craniosynostosis.

Advantages

dramatic improvement in forehead shape and gives the brain room to grow
complication rate is low.

Complications

risk of infection, bleeding
risk of damaging the dura (outside lining of the brain)
asymmetry, scarring
need for further surgeries to optimise the physical outcome when the child has finished growing.

Spring cranioplasty

Spring cranioplasty is an option for children with sagittal craniosynostosis who are too old for strip craniectomy and helmet therapy.

It is a two stage procedure.

The first procedure involves unfusing the fused suture by cutting through it. Two metallic springs are then placed to make the skull wider.
These are removed at a second smaller procedure 3 months later.

It is most effective when performed early in infancy, between the ages of 5-7 months of age.

Advantages

less invasive compared to other procedures
blood loss and blood transfusion risk is minimised
high success rate, avoiding larger, more invasive types of surgical correction.

Complications

incomplete correction
infection of the springs
need for additional interventions as the child grows.

Total calvarial remodelling

The entire skull is reconstructed in this procedure. It involves the complete removal of the affected skull bones, reshaping them, and then reattaching them.

Total calvarial remodelling is most commonly used to treat children with sagittal synostosis who are too old for either strip craniectomy or spring cranioplasty.

Advantages

comprehensive and customised solution for severe head shape deformities
procedure gives the brain room to grow and normalises the shape of the skull.

Complications

major surgical procedure
blood transfusions are commonly required
risk of infection, asymmetry, damaging the dura (lining of the brain)
need for further treatment interventions.

Management

Treatment without surgery

No medical treatment exists for craniosynostosis. Because of the progressive nature of the cranial deformity, most children with craniosynostosis are recommended for surgery.

However, children with mild deformities or those who present late without signs of increased intracranial pressure (ICP) are occasionally treated without surgery.

Helmet therapy

Helmet therapy helps mould the skull into a typical shape as the infant's head continues to grow. The helmet therapy starts a few days after the strip craniectomy surgery (see 'Treatment' above).

The helmet is worn 23 hours a day until the child is over 9 months.

Resources and more information

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