Brachycephaly is a deformity in which the head shortens in the anteroposterior direction, becomes wide. Occurs due to premature overgrowth of cranial sutures (formation of synostoses). It is often accompanied by intracranial hypertension, which, in the absence of therapeutic measures, can lead to violations of the child’s mental development, the occurrence of neurological symptoms. It is often combined with facial deformities. It is diagnosed based on the results of the examination, the data of hardware research methods. Early surgical treatment is required.
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Brachycephaly in the broad sense is a round head. In anthropology, the term is used to describe variants of the shape of the skull in representatives of different races. This type can occur in people of any nationality, but is more often detected in some Mongoloids and Melanesians, does not require treatment. Pathological brachycephaly should be distinguished from physiological brachycephaly. This term is used in medicine, denotes the deformation of the cranium, which is caused by the premature appearance of synostoses, entails unfavorable aesthetic and organic consequences, needs surgical correction.
The immediate cause of the violation of the shape of the skull is premature bilateral overgrowth of the coronal suture. Hereditary predisposition is revealed. In many patients, pathology is part of rare genetic syndromes: Kruzon, Pfeiffer, Aper, Setre-Chotzen. This group of diseases is characterized by a combination of deformities of the skull, abnormalities of limb development or axial skeleton. Most mutations affect the FGFR2 gene. They can be transmitted by autosomal dominant type or occur spontaneously.
In some diseases, de novo mutations are associated with the age and gender of the parent. For example, with Aper syndrome, the defect appears more often in the gametes of the father, the probability of mutation increases with age. The prevalence of pathologies is low, most often (with a frequency of 1 patient per 65 thousand newborns) there is Cruson syndrome. Isolated brachycephaly is diagnosed less often as syndromic. In both groups of patients, girls predominate (66-79%).
The coronal suture is located between the frontal and parietal bones. Its premature fusion limits further growth in the sagittal direction, therefore, with brachycephaly, the head begins to grow sideways and upwards. When combined with other synostoses, the skull may acquire an unusual appearance, for example, a leaf of clover. The shape of the head in multiple synostoses is determined by the order of occurrence and the severity of splices.
Due to the significant area of fusion with bilateral fusion of the frontal and parietal bones, the likelihood of developing intracranial hypertension increases, which can cause mental retardation, neurological disorders. An increase in intracranial pressure is detected in every third patient. Variants of facial deformities are determined by the severity of changes in the shape of the head, the type of syndrome. Brachycephaly is often combined with hypertelorism (abnormally wide-spaced eyes).
A common feature of patients with brachycephaly is a wide, high, short skull. The forehead is vertical, large, flat or protruding at the top and “sinking” at the bottom. The concavity of the supraorbital margin is detected with the subglacial unchanged. The back of the nose is expanded, low. Other possible signs are hypertelorism, some protrusion in the temporal areas. The details of the clinical picture depend on the type of disease.
It includes brachycephaly, depression of the middle zone of the face, symmetrical syndactyly of the fingers and toes. The head is enlarged, the fontanelles are expanded, form a significant defect along the middle line of the skull. Hypertelorism, exophthalmos, and often asymmetric are noted. The upper jaw is underdeveloped, malocclusion is observed. The tip of the nose is bent according to the type of beak.
These features are often combined with malformations of the brain: arachnoid cysts, jugular stenosis. A typical feature is a non-progressive enlargement of the ventricles, which requires differentiation with their expansion due to increasing hydrocephalus, which is rare in this pathology. A decrease in intelligence of varying severity is observed in 60% of patients.
The severity of syndactyly varies – from the fusion of the three middle fingers with partially free extreme to “hoof-like” hands with completely undivided fingers. Other possible anomalies include fused vertebrae, malformations of the trachea. Visual impairments are acquired in nature, occur due to deformations of the orbital region, include ametropia, anisometropia, strabismus, amblyopia. Keratopathy develops in 8% of patients due to incomplete closing of the eyelids. Atrophy of the optic nerve is detected in the same number.
It is characterized by the occurrence of a number of synostoses, hypoplasia of the face. Coronal sutures are most often involved in the formation of craniosynostoses, which causes the predominance of brachycephaly. Hypertelorism, exophthalmos, shortening of the upper lip are revealed. Due to the underdevelopment of the upper jaw, the lower one protrudes forward, a reverse bite is formed. At the time of birth, the changes are usually not clearly expressed, they become clearly visible after reaching 2 years, after which they continue to progress.
Distinct finger indentations are found in the skull area. CNS anomalies are less common, exophthalmos is more pronounced than in patients with Aper syndrome, but it has a symmetrical character. Sometimes it reaches such an extent that it is complicated by dislocation of the eyeballs. Progressive hydrocephalus is possible. Splices of the cervical vertebrae are found in every fifth child. In half of the patients, conductive hearing loss is detected, in 13% – atresia or narrowing of the external auditory canal.
It is characterized by brachycephaly, cutaneous syndactyly, extension and tilt of the thumbs of the upper and lower extremities. Possible malformations of internal organs, brachydactyly. It includes three subtypes. The first subtype is characterized by a favorable course. Changes in the shape of the face and skull resemble a softened version of the Aper syndrome. Intelligence is normal or slightly reduced. The lifespan is preserved.
The second subtype is manifested by multiple synostoses with deformity of the head in the form of a trefoil (clover leaf). Pronounced exophthalmos, decreased intelligence, ankylosis of the elbow joints are revealed. The third subtype in terms of the severity of the course, the presence of brachial synostosis resembles the second. The shape of the face and head – as in Crouzon syndrome. Both subtypes occur sporadically, are more severe than the first, and are more often combined with severe abnormalities of the development of the central nervous system. Life expectancy in the absence of treatment is reduced.
Any synostosis is possible, but coronary sutures are most often affected. Brachycephaly is combined with underdevelopment of the lower jaw. There may be an unusual shape of the ear, facial asymmetry, partial syndactyly, an increase of 1 finger. Symmetrical or asymmetrical ptosis is almost always detected. Intelligence, as a rule, is preserved. There is a significant variability of clinical manifestations.
Possible negative consequences of brachycephaly are intracranial hypertension, intellectual development disorders, and the appearance of neurological disorders. The risk of these complications increases with the increase in the number and area of synostoses. A certain negative role is played by venous anomalies, as well as hydrocephalus, which can aggravate these complications.
Visual disturbances are a consequence of intracranial hypertension or develop against the background of exophthalmos. Patients have an incorrect bite, respiratory disorders may occur. The probability of certain complications depends on the type of brachycephaly. Thus, visual impairment is more typical for Crouzon syndrome, mental retardation – for Aper syndrome, 2 subtypes of Pfeiffer syndrome.
The primary diagnosis of brachycephaly is carried out by a pediatrician. The patient is then referred to a neurosurgeon. The nature of the pathology is determined taking into account the results of physical examination, data from instrumental studies. Interviewing parents does not always provide useful information, but sometimes helps to assess the development of symptoms over time, which may indicate a certain syndrome. The most important role is played by the examination of the patient, during which the parameters of the skull are measured, pathologies of the face and limbs are revealed.
Laboratory tests are not informative enough, they are used to confirm the genetic nature of the disease. Mutations of one gene can cause several types of syndromic brachycephaly, so test results often cannot be used for differentiation. As part of the survey , the following hardware techniques are prescribed:
- Neurosonography. It is used to assess the condition of cerebral tissues, determine the size of ventricles, detect intracranial hypertension.
- Skull x-ray. Confirms ossification of the coronal suture, with polysynostosis – fusion of several sutures. The images may show enlarged fontanelles, areas of bone thinning, pronounced finger depressions, indicating an increase in intracranial pressure.
- CT and MRI. Performed at the final stage of diagnosis. They allow you to detail the information obtained during other studies, to determine the preferred tactics of surgical treatment.
- Ophthalmological examination. It is carried out to identify possible concomitant visual impairments. Includes visometry, ophthalmoscopy, exophthalmometry, and other techniques.
Patients often require consultations with a dentist, maxillofacial surgeon. In case of limb abnormalities and vertebral fusion, an examination by a pediatric orthopedist is indicated. Differential diagnosis is carried out between isolated and syndromic forms of brachycephaly. Pathology is distinguished from other deformities of the skull, fractures, rickets, brain cysts.
Surgical operations are necessary, often multi–stage. The purpose of treatment is to eliminate functional problems and aesthetic defects, to prevent the adverse effects of brachycephaly. Interventions are carried out before the age of 1 year, optimally – at 6-9 months. During this period, the brain grows rapidly, the removal of mechanical obstacles allows you to create favorable conditions for increasing its size. According to statistics, the level of intellectual development in early operated patients significantly exceeds similar indicators in other groups of patients.
In case of respiratory disorders, a tracheostomy is required in the first days of life. Severe hydrocephalus is an indication for early ventriculoperitoneal bypass surgery. These measures make it possible to stabilize the condition of patients, to prepare them in the best way for a volumetric operation. Patients with severe exophthalmos, incomplete closing of the eyelids may require temporary stitching of the eyelids to prevent dislocation of the eyeballs, the development of keratopathy.
Surgical correction of nonsyndromic brachycephaly is performed by bifrontal trepanation of the skull. The shape of the forehead is changed by remodeling using a special tape or absorbable plate. With mild hypertelorism , the central section of the tape with a width of up to 2 cm is removed . The results are usually good, 4.3% of patients require repeated operations.
In syndromic brachycephaly, anterior reconstruction is the first stage of treatment. Along with the above method, various osteotomy options may be required, the movement of bone blocks with the mobilization of the eye socket and facial bones. Metal structures are removed after 1-3 months. The risk of unsatisfactory results in the presence of genetic syndromes increases, repeated operations to change the shape of the skull are necessary for 20% of patients.
Subsequently, interventions are performed to eliminate hypertelorism. After the occurrence of stable occlusion, facial traction is applied to correct the bite and the shape of the jaws. The list of other surgical techniques depends on the presence of brain development abnormalities, syndactyly, and other pathologies.
The prognosis is determined by the type and severity of brachycephaly, the presence of other malformations, the quality of preoperative preparation, and the timeliness of the operation. A favorable outcome is more often observed in patients with isolated pathology. With genetic syndromes, the volume and number of interventions increases, and unsatisfactory correction results are more often revealed.
Facial deformities often have to be eliminated in several steps until adolescence. Other anomalies have a certain influence on the forecast. Nevertheless, with the optimal choice of the timing of operations, the use of modern techniques, in most cases it is possible to achieve a satisfactory aesthetic and clinical effect.
There is no specific prevention of brachycephaly. The list of non-specific measures includes medical and genetic consultations to identify genetic syndromes, pregnancy planning, healthy lifestyle, exclusion of exogenous negative factors to prevent cases of isolated pathology unrelated to adverse heredity.