Craniosynostosis (premature closure of cranial sutures)

The human skull consists of several skull bones that come together and grow together at so-called cranial sutures. Until early childhood, these cranial sutures are open so that the brain can grow unhindered. Later, they close.

The skull has four large cranial sutures: the metopic suture (frontal suture), the coronal suture (coronal suture), the saggital suture (arrow suture) and the lambdoid suture (lambdoid suture). If one of these cranial sutures closes prematurely, this is also referred to as craniosynostosis. Several cranial sutures can also close prematurely at the same time. One child is affected by craniosynostosis for every 2000 to 2500 births worldwide. The exact cause of craniosynostosis is not known. It most frequently occurs sporadically (by chance). However, it can also occur as part of rare craniofacial syndromes that affect the skull and face. Examples include Apert syndrome, Pfeiffer syndrome and Crouzon syndrome. Premature closure results in an altered skull shape, which can inhibit the expansion and development of the brain under certain circumstances.

Typical shapes

In paediatric neurosurgery, we distinguish between the four most common skull deformities:

• Sagittal suture synostosis leads to a so-called «scaphocephalus». This is by far the most common craniosynostosis and occurs in 1:5000 births.
• Coronal suture synostosis leads to a so-called «anterior torticollis» (plagiocephalus). It can be unilateral or bilateral. This form occurs in 1:11000 births.
• Synostosis of the metopic suture leads to a so-called «triangular skull» (trigonocephalus). This form occurs in 1:15000 births.
• Lambdan suture synostosis leads to a «posterior oblique head» (plagiocephalus). This form is very rare and occurs in 1:200,000 births.

Much more common than craniosynostosis are skull deformities caused by the child lying on its back for long periods. The so-called «positional plagiocephaly» is usually reversible and does not require paediatric neurosurgical treatment. Neither a developmental disorder nor increased intracranial pressure is to be expected.

Sometimes it can also be mistakenly interpreted as craniosynostosis if a palpable ridge forms on the skull in early childhood. However, such a «benign metopic ridge» occurs during normal closure of the metopic suture. This also does not require neurosurgical treatment.

Rarer forms

A general distinction is made between a single suture synostosis and a synostosis of several sutures (multi suture synostosis). Single suture synostosis is generally not familial and usually occurs sporadically. Multiple suture synostosis, on the other hand, is often familial. However, they can also occur as part of typical syndromes.

Craniosynostoses in the context of syndromes are relatively rare. These are usually random newly occurring genetic mutations. In these children, several cranial sutures are often affected at the same time, whereby other parts of the body, such as the face, hands, feet, etc., are often also affected as part of the syndrome and must be treated accordingly. The syndromes in which craniosynostosis occurs most frequently are Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, Carpenter syndrome and Saethre-Chotzen syndrome.

• Apert syndrome occurs in about 6 to 15.5 per 1 million births and is characterised in particular by bilateral coronal suture synostosis and an underdeveloped upper jaw bone.
• Crouzon syndrome occurs in about 16 per 1 million births and also manifests itself particularly through bilateral coronary suture synostosis.
• Pfeiffer syndrome is very rare and occurs in three different forms, each of which is characterised by a different degree of concomitant disease. Pfeiffer syndrome is also characterised by bilateral coronary suture synostosis.
• Carpenter syndrome and Saethre-Chotzen syndrome are extremely rare and are characterised in particular by craniosynostosis of the coronal, sagittal and lambdoid sutures (Carpenter syndrome) and the coronal, metopic and lambdoid sutures respectively.

Craniosynostosis is typically detected within the first few months of life due to a conspicuous or altered head shape. If craniosynostosis is not treated in time, symptoms of increased intracranial pressure can occur in very rare cases due to constricted space in the head. In these cases, affected children complain of headaches, have to vomit and show slight irritability, weight loss or loss of appetite as well as delayed development, visual disturbances or cognitive impairments. In addition, craniosynostosis can change the shape of the head, resulting in an aesthetically unsatisfactory appearance.

Craniosynostosis is usually diagnosed on the basis of the clinical appearance (the typical signs of craniosynostosis) and the visible shape of the head. Therefore, imaging is often not necessary. An ultrasound of the cranial sutures can confirm the diagnosis of craniosynostosis, but is not necessary in most cases. Today, an X-ray is not necessary. A computerised tomography (CT) scan is only useful if craniosynostosis of the metopic or coronal suture is present so that open surgery can be planned.

If your child is suspected of having a genetic form of craniosynostosis, one of our genetics experts will advise you and refer you to the relevant specialists at UKBB as required.

The treatment of choice for diagnosed craniosynostosis is surgical correction of the skull shape. The surgical technique differs depending on the type of craniosynostosis.

In principle, all forms of craniosynostosis can be operated on minimally invasively using a camera-guided endoscope or openly. The endoscopic technique requires a smaller skin incision and, after the operation, the skull moulding is supported with a customised helmet.

During the entire hospital stay, your child will be looked after by our paediatric neurosurgery team at UKBB. Your child will arrive one day before the operation, will be examined again by our paediatric neurosurgery team and the anaesthetists and can then sleep at home if you wish. Your child will be operated on the next day. He or she will then be transferred to the intensive care unit (1st floor) for monitoring.

On the day of the operation, a companion from the Pro UKBB Foundation's parental support service (BELOP) will be at your disposal. She will accompany you until your child has fallen asleep and show you where he or she will wake up. In the meantime, she will help you to find your way around the hospital. As soon as your child no longer needs close monitoring (usually the following day), he or she will be transferred to the paediatric surgery ward (2nd floor).

As a rule, your child will recover from the operation after three to five days and will also be allowed to go home during this period. During the entire hospitalisation, you may be with your child and contact the paediatric neurosurgery team, who will visit you and your child daily for rounds.

The prognosis of treated craniosynostosis is generally excellent. Children with sporadic craniosynostosis can expect very good cosmetic results as well as normal development and quality of life. Children who are operated on during the first year of life tend to develop better than children who are older at the time of surgery. Development also depends on the type of craniosynostosis and the accompanying problems. A second operation may be necessary if the sutures close again. This occurs in around 14% of cases and is more common in children with craniosynostosis as part of a syndrome.

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