Dysplastic scoliosis

Among the scoliosis-related deforming dorsopathies that have the code M40-M43 in the International Classification of Diseases (ICD-10), there is no dysplastic scoliosis. Although there is code M41.8 - other forms of scoliosis, one of which is scoliosis due to dysplasia, that is, an anomaly in the development of structures of the lumbosacral spine during embryogenesis.

Epidemiology

According to clinical statistics, pediatric idiopathic scoliosis is 1.7%, with most cases aged 13 and 14 years, and small scoliotic curves (10-19 degrees) were the most common (prevalence of 1.5%). [1]The ratio of women to men ranges from 1.5: 1 to 3: 1 and increases significantly with age. In particular, the prevalence of curves with higher Cobb angles is significantly higher in girls than in boys: the ratio of women to men increases from 1.4: 1 in curves from 10 ° to 20 ° to 7.2: 1 in curves> 40 °. [2]

In 90-95% of cases, right-sided dysplastic chest scoliosis is observed, in 5-10% of cases - idiopathic or dysplastic left-sided scoliosis of the lumbar spine (right-sided lumbar scoliosis is rare).

According to the Scoliosis Research Society, juvenile scoliosis accounts for 12–25% of cases; girls are diagnosed more often than boys. [3]Typical localization is the thoracic spine; up to about 10 years, the pathology progresses slowly, but has a higher likelihood of developing severe deformity that is not amenable to conservative treatment.

The most common dysplastic scoliosis in adolescence is with a general incidence in the population of up to 2% (with a predominance of girls).

At the same time, dysplastic thoracolumbar scoliosis is observed four times more often than lumbar scoliosis.

Causes of the dysplastic scoliosis

Western and many domestic experts in the field of orthopedics and pathology of the spine do not distinguish dysplastic scoliosis: it is referred to the idiopathic form, since the causes of many congenital anomalies in the development of spinal structures have not yet been established. Idiopathic scoliosis, in a sense, is a diagnosis of exclusion. However, idiopathic scoliosis is by far the most common type of spinal deformity. [4]It should be noted that at least 80% of  scoliosis in children  is idiopathic. [5]But as a final diagnosis, it is determined after the exclusion of genetically determined generalized syndromes, accompanied by  congenital scoliosis .

Some experts associate the etiology of idiopathic or dysplastic scoliosis with genetics, since the spine is formed before birth, and this pathology is observed in the genus: according to the Scoloosis Research Society, almost a third of patients. And there is an opinion that scoliosis due to dysplasia is a multigenic dominant state with multivariate gene expression (but specific genes have not yet been identified). [6]

Other researchers, analyzing and systematizing clinical cases, see the causes of this pathology in metabolic disorders or teratogenic effects of various etiologies.

Nevertheless, congenital morphological disorders of the spine (primarily in the lumbosacral region), which can lead to its three-dimensional deformation, are considered:

• spinal hernia, in particular,  meningocele ;
• non-growth of the posterior vertebral arch -  cleft of the spine  or spina bifida;
• spondylolysis - dysplasia of the vertebral arches with interarticular diastasis (gap);
• abnormalities of the spinous processes of the vertebrae;
• developmental defect (in the form of a wedge) of the bodies of the first sacral vertebra (S1) and fifth lumbar (L5);
• inferiority of connective tissue structures of the spine in the form of dysplasia of the intervertebral discs.

When diagnosing dysplastic lumbar scoliosis in patients, ontogenetic disorders of spinal segmentation such as lumbarization and sacralization can be detected.

With lumbarization (lumbar vertebrae - the lumbar spine) in the embryonic period, the so-called transitional lumbosacral vertebra is formed, then the vertebra S1 does not merge with the sacrum and remains mobile (sometimes it is designated L6).

Sacralization (os sacrum - sacrum) is a condition in which, during the period of intrauterine skeleton formation, the transverse spinous process of the L5 vertebra merges with the sacrum or ilium, forming a partial pathological synostosis. According to statistics, these anomalies are found in one infant in 3.3-3.5 thousand newborns.

Risk factors

The risk of developing dysplastic scoliosis is increased in the presence of the following factors:

• scoliotic deformity of the spinal column in a family history;
• violations of intrauterine development in early pregnancy (during the first 4-5 weeks), causing congenital defects of the structures of the spine;
• age and gender. This refers to the immaturity of the spine in children during their heightened growth: from infancy to three years and after nine years, as well as with the onset of puberty - puberty in adolescents, especially girls, whose disease often progresses and requires surgical intervention.

Pathogenesis

Explaining the pathogenesis of spinal column deformation in the frontal plane, which is accompanied by simultaneous twisting (torsion) of the vertebrae, orthopedists and vertebrologists note not only the  anatomical and biomechanical features of the spine , but also the factors of its normal or abnormal formation at the initial stage of intrauterine development - during somitogenesis.

Experts say that almost all congenital defects in the structures of the spine of the unborn baby are "laid" before the end of the first month of pregnancy, when the cell is rearranged in the cytoskeleton. And they are associated with violations of the processes of formation and distribution of somites - paired segments of mesodermal tissue.

As for the pathophysiology of spinal deformity in dysplastic scoliosis, for example, congenital morphological disorders of the vertebral bodies - the formation of so-called sphenoid vertebrae or half-vertebrae - cause asymmetry and compensatory changes (curvature) of neighboring vertebrae. As the child grows, ossification zones (ossification nuclei) are formed on the surfaces of the vertebral joints, and the formation of spongy bone tissue instead of cartilage leads to consolidation of the deformation of the spinal column.

With defects of the spinous processes, the surfaces of the vertebral joints are displaced by the joint (in case of their underdevelopment), or - when the processes are hypertrophied - their articulation is disrupted. The stability of the spinal column due to dysplasia of the intervertebral discs is also lost.

Symptoms of the dysplastic scoliosis

What are the clinical symptoms of dysplastic scoliosis? They depend on the localization of the pathological process and the degree of frontal deviation of the spinal column. 

By localization are distinguished:

• dysplastic thoracic scoliosis - with the upper point of curvature of the spine at the level of thoracic vertebrae T5-T9;
• thoracolumbar scoliosis - in most cases S-shaped, that is, with two oppositely directed arches of curvature in the frontal plane; the apex of the lumbar arch is noted at the level of the first lumbar vertebra (LI), and the contralateral thoracic arch - in the region of the vertebrae T8-T11;
• lumbar scoliosis - with an apical point of curvature in the area of the lumbar vertebra L2 or L3.

About a quarter of patients with idiopathic scoliosis (AIS) have adolescent back pain. [7]Symptoms may also include paresthesia and paresis of the extremities, deformation of the toes, loss of tendon reflexes, variability of blood pressure, pollacuria and nocturnal enuresis. [8]

See also -  Symptoms of scoliosis .

Stages

According to the adopted methodology, specialists determine the size of the curvature arc - the degree of deviation (Cobb angle) from the x-ray of the spine:

• dysplastic scoliosis of 1 degree corresponds to a curvature angle of up to 10 °;
• 2 degrees is diagnosed with a Cobb angle in the range of 10-25 °;
• 3 degrees means that the deviation of the spine in the frontal plane is 25-50 °.

Higher values of the Cobb angle give rise to ascertain scoliosis of 4 degrees.

At 1 degree of curvature, both the first signs and severe symptoms may be absent. The progression of the pathology begins to manifest itself in posture disorders with a skew line of the waist and different heights of the shoulder blades and shoulders.

With lumbar scoliosis, a pelvic skew occurs, which is accompanied by bulging of the upper edge of the ilium, a feeling of shortening of one leg and limping.

With scoliosis of 3-4 degrees, pain in the back, pelvic region, lower limbs may appear. Rotation of the vertebrae with an increase in the angle of curvature leads to bulging ribs and the formation of the front or rear hump.

Complications and consequences

Any scoliosis with a frontal deviation of the spine of more than 40 ° has negative consequences and gives complications, and this is not only a hump disfiguring the body. According to the study, progression of scoliosis was observed in 6.8% of students and in 15.4% of girls with scoliosis of more than 10 degrees at the initial examination. In 20 percent of children with 20 degree curves, there was no progression during the initial examination. Spontaneous improvement of the curve occurred in 3% and was more often observed on curves of less than 11 degrees. Treatment was required for 2.75 children per 1000 examined. [9]

Since the progression of curvature is associated with growth potential, the younger the patient in the initial stage of scoliosis, the greater the degree of deformation of the spinal column.

So, dysplastic thoracolumbar or lumbar scoliosis, which develops in children under the age of 5 years, can disrupt intraorgan blood flow and adversely affect the cardiopulmonary, digestive and urinary systems. [10]

Diagnostics of the dysplastic scoliosis

Detailed information identifying this disease in the material -  Diagnosis of scoliosis .

Instrumental diagnostics is primarily carried out using radiography and  spondylometry , as well as  computed tomography of the spine .

See also -  Methods of examination of the spine

MRI of the brain and spinal cord may be required - to rule out CNS disorders in patients younger than eight years old with a spinal curvature angle of more than 20 °.

Differential diagnosis

Differentiation of some diseases accompanied by spinal deformity is necessary  . In addition, differential diagnosis is important for determining stable or minimally progressive scoliosis, which can be observed and corrected, and scoliosis with a large compensating lateral curvature and vertebral torsion and a high risk of an increase in the angle of curvature. In the second case, a referral to an orthopedic surgeon is necessary.

Treatment of the dysplastic scoliosis

Methods and techniques for treating dysplastic scoliosis  -  including  physiotherapeutic treatment  (various procedures, exercise therapy, massage)  [11]- are described in detail in the publications:

• Scoliosis treatment

In which cases, surgical treatment is necessary to correct spinal deformity , [12]and how it is carried out is described in detail in the articles:

• Surgical treatment of scoliosis
• Scoliosis: operation

Prevention

Dysplastic scoliosis, according to experts at the Pediatric Orthopedic Society of North America, cannot be prevented.

However, early detection of deforming changes in the spine, that is, prevention of severe curvature, is possible by screening. Children's orthopedists should examine girls at 10 and 12 years old, and boys should be checked once at 13 or 14 years old. [13]

Forecast

After the diagnosis of dysplastic scoliosis has been made, the prognosis is associated with a risk of progression of the deformity.

The determining factors are: the magnitude of the curvature at the time of diagnosis, the potential for future growth of the patient and his gender (since girls have a much higher risk of progression than boys).

The stronger the spinal column is curved, and the greater the growth potential, the worse the prognosis. Growth potential is assessed by determining the stage of sexual development according to Tanner and the degree of ossification in accordance with Risser's apophysial test. [14]

If untreated, dysplastic scoliosis of degrees 1, 2, and 3 in an adolescent will progress on average by 10-15 ° throughout life. And with a Cobb angle of more than 50 °, its increase is 1 ° per year.