What is Craniosynostosis?

Craniosynostosis is the premature overgrowth of one or more sutures of the skull, leading to the formation of characteristic deformity. Craniosynostosis is understood as brain damage that occurs when the skull cavity is not sufficiently expanded during the period of the most active brain growth.

In the CIS countries (Ukraine, Russia, Belarus, etc.), a disease is recognized easily, but it is diagnosed in rare cases. The diagnosis is made after 12 months, because of which the prognosis worsens and a lot of complications arise.

According to international data, premature closure of one of the sutures of the skull on average is recorded in one of 1 thousand newborns, that is, the percentage of patients among infants is 0.02-4%. The frequency of syndromic craniostenosis 1: 100 000-300 000.

Division of the disease due to occurrence was proposed in 1986 by M. Cohen:

  • nonsyndromal
  • syndromal

Syndromic, in turn, is divided into:

  • X-linked craniosynostosis
  • monogenic craniosynostosis
  • syndromes caused by environmental factors
  • incomplete syndromic
  • chromosomal craniosynostosis

Monosynostoses, polynostosis, pansinostosis are distinguished by anatomical signs.

Monosynostoses are of the following types:

  • isolated metopic craniosynostosis
  • isolated sagittal craniosynostosis
  • isolated coronary bilateral craniosynostosis
  • isolated coronary unilateral craniosynostosis
  • isolated lambdoid bilateral craniosynostosis
  • isolated lambdoid unilateral craniosynostosis

Monosynostosis, which is an early closure of 1 suture of the skull, is almost always diagnosed. When two or more sutures are included in the process, polysynostosis is diagnosed. Pansinostosis occurs in extremely severe cases. An isolated craniosynostosis is diagnosed if, with premature synostosis, there are no other malformations in the child.

Causes of Craniosynostosis

The nature of this disease has been little studied to date. But there are a large number of theories of the occurrence of craniostenosis. Theories talk about such reasons:

  • hormonal
  • intrauterine
  • hereditary disorders
  • compression of the fetal head in the uterus, etc.

A defect in the gene for fibroblast growth factor receptor (FGFR) 1,2,3 is officially recognized as a factor in pathogenesis.

The main seams of the cranial vault:

  • coronary
  • sagittal
  • metopic
  • lambdoid

If the bone suture is affected, compensatory bone growth is fixed perpendicular to its axis, which is called the Virchow’s law in meditation. As a result of this process, a characteristic deformation arises – one for each of the closed joints. Sagittal craniostenosis causes scapocephaly, and synostosis of the entire coronary suture causes plagiocephaly. If there is a synostosis of the metopic suture, trigonocephaly occurs.

Synostosis of the entire lambdoid suture or its half leads to deformation of the occipital region. Its degree directly depends not only on the degree of synostosis and the number of sutures included in the deformation, but also on the state of the brain itself. For example, if there is hydrocephalus along with this, then the severity increases.

Pathogenesis during Craniosynostosis

It is possible to speak about premature synostosis of skull sutures if a large fontanel is closed early. If with syndromic synostosis 2 or more sutures are involved in the process and if there is a concomitant expansion of the ventricles of the brain, the large fontanel may not be closed until the baby is 3 years old. With premature synostosis of the sutures of the skull, panoramic radiographs show finger impressions.

The pattern of finger impressions becomes stronger if other compensatory mechanisms cannot cope with intracranial hypertension. In newborns, finger impressions may also be visible. Another pathognomic sign of increased pressure in the middle of the skull is venous congestion in the fundus and edema of the optic nerve. If a person has isolated monosynostosis, the above-mentioned phenomenon may not be fixed. With polysynostosis, intracranial hypertension, which has existed for a long time, causes the formation of partial atrophy of the optic nerves.

Symptoms of Craniosynostosis

Sagittal craniosynostosis
With this type of disease, the anteroposterior size of the skull increases, while the width decreases. one can notice that the child’s head is sharply elongated in the longitudinal direction, and the occipital and frontal region hang over, while the temples are as if pressed. Such changes lead to the fact that the face of the child becomes oval and narrow. This type of deformation is called scaphocephaly or scaphoid skull.

Netopic craniosynostosis (trigonocephaly)
Among isolated craniosynostoses, this species is least likely to occur. A triangular deformation of the frontal part of the head is formed, a bone keel is formed, which goes from the overhead to the large fontanel. Observe hypotellorism. Most doctors consider trigonocephaly as a component of syndromes such as Oro-facio-digital or Opitz. With the growth of the child, the deformation of the forehead becomes not so noticeable due to the fact that the tops of the crest are smoothed out and the frontal sinuses develop. But nevertheless, the curvature of the frontal bone is visible, there is a turn of the infraorbital edges outward, hypothellism remains. There may be brain damage, but they cannot be predicted. Visual disturbances are likely, there is a delay in the development of the child’s intelligence.

Unilateral coronary craniosynostosis
The coronary suture with the pathology under consideration is located perpendicular to the median axis, two equal halves are observed in its composition. If one of them prematurely heals, a typical asymmetric deformation occurs, which is called plagiocephaly in the medical literature. In a child, the upper orbital edge of the orbit and frontal bone is flattened on the side that is affected. And the other half of the forehead hangs – a compensatory development mechanism.

The older the child becomes, the more flattening of the zygomatic region is, and the nose is bent to the unaffected side. From about 6-7 years old, the bite begins to deform, because the height of the upper jaw becomes more and more. The consequence of this is the displacement of the lower jaw on the side of the prematurely closed suture.

Visual impairment is observed with this type of craniosynostosis, most often this is squint. Plagiocephaly can be taken for the features of the postpartum configuration of the head, but it does not disappear in the first 14-21 days of life.

Bilateral coronary craniosynostosis
It occurs in about 15-20 cases out of 100. In such cases, a wide flattened with a flat high forehead is formed, while the upper orbital edges are flattened. This form is called “brachycephaly.” If the cases are severe, it is recognized by the tower shape of the head, it is pointed up, which is called acrocephaly.

The neurological picture is nonspecific; at earlier times, ophthalmological and neurological phenomena are more pronounced. Presumably, this is due to the large length of the seam.

Lamb-shaped craniosynostosis
The lamboid seam, similar to the coronary, is divided into 1 parts at the point of contact with the sagittal suture. Therefore, the child may have unilateral or bilateral damage.

In almost all cases, the unilateral nature of the lesion is observed with the form of craniosynostosis under consideration. A flattening of the occipital part appears, occipital plagiocephaly is formed. It is very difficult to diagnose this synostosis, because the unilateral neck fusion is in most cases regarded by diagnosticians as “positional”, which occurs due to the forced position of the baby’s head on its side. This situation happens when a child has a unilateral increase in muscle tone or with a diagnosis of torticollis.

Synostosis in such cases can be distinguished by the fact that with age it practically does not change, although it is determined even at the birth of a child. Positional plagiocephaly progresses significantly when a child is given physiotherapy. Under the baby’s hair, deformation is visible only a little, there are no bright neurological manifestations. Therefore, lambdoid synostosis in this group of diseases is difficult to diagnose. However, early diagnosis and proper treatment is recommended because there is a risk of neurological disorders.

Syndromic craniosynostosis
This is the rarest and most complex group of congenital diseases of the craniofacial region. Surgical correction is difficult, and it is also very difficult to make a prognosis of mental and neurological development. In children, not only the growth of the bones of the facial skull is disrupted, but there are problems with breathing, vision, and cosmetic deformity is expressed.

The main symptom: brachycephaly against the background of premature synostosis of the coronary suture. The upper jaw is underdeveloped, because there is an indented facial deformity with exophthalmos and orbital hypertellioriem. The process of breastfeeding is disturbed, because it is difficult for him to breathe, and the correct position of the jaws is disturbed.

With syndromic craniosynostosis, coronary and other sutures quite often overgrow, which leads to craniostenosis. Therefore, in addition to problems with breathing and nutrition, the child also receives neurological disorders. In such cases, early surgical intervention is important. In many children with syndromic craniosynostosis, a large fontanel is sharply enlarged, there may be an extension of the sagittal suture along the entire length. In the diagnosis, this gives certain difficulties, because an extended fontanel is combined with premature overgrowth of sutures.

Patients with syndromic synostosis with unqualified care die before 12 months of life during frequent and severe respiratory diseases, the complications of which are pneumonia. If there is no surgical treatment for such patients, neurological and mental problems are later observed in children.

Diagnosis of Craniosynostosis

Such instrumental diagnostic methods as CT (computed tomography) with 3-dimensional remodeling of the image of the bones of the cranial vault and face are effective. The study reveals signs of hypertension inside the skull, confirms stenosis in the case of isolated damage, allows doctors to establish all interested sutures in cases of polysynostosis.

Premature synostosis of cranial sutures can be detected during a doctor’s examination. Craniosynostosis is noticeable in the shape of the child’s head. Such children have a non-standard shape of the skull, which is combined with deformation of the facial skeleton. If a child has synostosis of more than 2 stitches, there is a clear tendency to increase the degree of neurological deficit in proportion to the number of stitches involved.

If more than 2 sutures are affected, craniostenosis is diagnosed. Neurological manifestations can appear at the age of 2-3 years, as a rule. But with such a late diagnosis, brain damage due to illness is always detected.

Differential diagnosis
Deformations of the skull in a child arise not only from early synostosis of sutures. Or craniosynostosis can occur as a result of some damage to the brain, which leads to a halt in the processes of its growth. In such cases, operations are needed only for cosmetic purposes, because, unfortunately, the baby will no longer have functional advancements after surgery.

The most common example of nonsynostotic cranial deformity is positional plagiocephaly. The head changes in a newborn child, its spontaneous motor activity is limited, because the head is turned in one or the other direction. The reason for this condition is often in torticollis or dystonic disorders, which are the result of perinatal encephalopathy.

The difference between the positional deformation of the skull and craniosynostosis in newborns is that it manifests itself in the first weeks after the birth of the baby. A synostosis is already at birth. The deformation can become much smaller or disappear altogether if the child is properly looked after, exercise therapy, physiotherapy, massage and normalize the position of his head using various devices.

The swelling or sinking of certain areas of the head is observed when a history of any deviation in the normal course of childbirth or the early postnatal period is indicated.

Craniosynostosis should also be differentiated from microcephaly in children. It is also typical for her to prematurely close the fontanelles and sutures of the skull. In some cases, there may be true synostosis of individual cranial sutures in inadequate periods. With microcephaly in a newborn, synostosis of sutures occurs gradually. Lag of psychomotor development in children with microcephaly occurs earlier and is always much more difficult than with craniostenosis.

Microcephaly differs from craniosynostosis, primarily by signs of brain damage and the absence of signs of increased intracranial pressure. This can be detected using neuroimaging methods, such as CT or MRI.

Craniosynostosis Treatment

The treatment of craniosynostosis is that they perform surgical intervention in a specialized clinic. To date, the techniques are so developed that patients almost never experience complications. The earlier a child has been diagnosed with craniosynostosis, the greater the chances of a successful outcome of the operation, the better the cosmetic result (type of face and skull).

The brain grows most actively while the child is not yet 2 years old. By the time the child is 2 years old, his brain already has 90% of the adult’s volume. Therefore, craniostenosis can be prevented only with the help of early surgical intervention. Doctors believe that the disease in question can be effectively treated at the age of 6-9 months. Since at this age it is easy to manipulate the bones of the skull of the baby, the final remodeling of the shape of the skull by the rapidly growing brain is facilitated. At the age of 6-9 months, residual bone defects heal more fully and faster.

If the disease is diagnosed late, and the child undergoes surgery when he is already 3 years old, then there is almost no chance that the functions of the eyes and brain will improve. The operation in such cases will only improve the appearance of the child, no more. Modern treatment allows not only to increase the cranial volume, but to correct its shape to a more or less correct one.

Treatment is most effective with the collaboration of a maxillofacial surgeon and a neurosurgeon. Surgical treatment consists in remodeling the bones of the cranial vault. For this, the bones of the deformed sections are removed and rearranged to the correct anatomical position, as a result of which the cranial cavity increases.