Scoliosis as a factor in the development of back pain

Among the structural deformations of the spine, the most common are idiopathic scoliosis (i.e. scoliosis with an unclear etiology), the prevalence of which in the population reaches 15.3%. The frequent presence of manifestations of dysraphic status in patients with idiopathic scoliosis allowed E. A. Abalmasova to distinguish dysplastic scoliosis in this group. At the same time, clinical manifestations, the nature of progression and the principles of prognostication of idiopathic and dysplastic deformations are often of the same type.

In foreign literature, the term "dysplastic scoliosis" is practically not used. In foreign countries, the leading principle of classification of idiopathic scoliosis is currently the age division of deformations proposed by JIP James (1954):

• Scoliosis in young children: develops in the first 2 years of life, is more often observed in boys, is more often left-sided, with long, gentle arcs, and regresses in most cases.
• Juvenile scoliosis: develops between the 3rd year of life and the beginning of puberty, is more often observed in girls, is more often right-sided, and progressive.
• Adolescent scoliosis: the onset of development coincides with the period of puberty and continues until the end of bone growth. In the vast majority of cases (up to 85%), it is observed in girls, progression is determined by the potency of bone growth.
• Scoliosis in adults: develops after the completion of bone growth.

Based on the study of the clinical course of idiopathic scoliosis in almost 25 thousand adolescents, King J. H. Moe, D. S. Bradford, R. B. Winter (1983) identified five typical variants of deformation. Subsequently, this division became known as the King classification (named after the first author). Unfortunately, the King classification was published in Russian literature only in 1998.

Classification of idiopathic scoliosis in adolescents according to King

Type of deformation	Characteristic of deformation
Trail	S-shaped scoliosis: right thoracic, Left-sided lumbar curve; Both arches are structural, the lumbar one is more rigid; The magnitude of the lumbar curvature exceeds The size of the thoracic arch; The deformation is usually compensated.
Type II	S-shaped scoliosis: right-sided thoracic, left-sided lumbar curve; both curves are structural; the magnitude of the thoracic curvature exceeds the magnitude of the lumbar curve; the lumbar curve is more mobile; the deformity is usually compensated
Type III	Right thoracic C-shaped scoliosis (usually T4 to T12-L1); Lumbar curvature is absent or minimal; Decompensation is minor or absent
Type IV	Long C-shaped right thoracolumbar curve (lowest vertebra - L3 or L4); significant decompensation
Type V	S-shaped double thoracic arch: upper left-sided arch (T1-T5), lower right-sided; both arches are structural, the upper arch is more rigid

It is important to emphasize that the deformations presented in this classification are classified in foreign literature as "typical" idiopathic scoliosis of adolescents. The classification is also particularly valuable due to the fact that type II deformation according to King is currently used as a basic model in determining the tactics of applying support structures of CD instrumentation.

The use of the term typical adolescent scoliosis has led to the introduction of the concept of atypical deformations. We have not found any descriptions of atypical scoliosis in Russian literature, so we pay special attention to them:

• left-sided scoliosis of the mid- and lower thoracic region,
• thoracic scoliosis with short 3-4-segment arcs,
• scoliosis not accompanied by vertebral torsion.

The presence of signs of atypicality, regardless of the magnitude of the deformation, is an indication for in-depth clinical and radiological examination. According to RB Winter, JE Lonstein, F. Denis (1992), in almost 40% of cases of atypical deformations, a fairly rare pathology of the spine or spinal cord is detected - tumors, syringomyelia, neurofibromatosis, Arnold-Chiari syndrome, various types of spinal cord fixation. At the same time, in typical idiopathic scoliosis, various types of myelopathies and myelodysplasias were detected by the authors only in 3-5% of cases. These data explain the need for early MRI of the spine and spinal cord in atypical scoliosis in adolescents.

Determining the probability of progression of scoliotic deformations. One of the key moments in determining the treatment tactics for scoliosis is predicting the probable progression of the deformation. This indicator is determined by many factors - primarily such as the size of the scoliotic arc, the age of the child at the time of the initial detection of the deformation, the degree of maturity of the skeleton, etc.

Probability of scoliosis progression in adolescents (summary data).

Author	Year	Number of observations	Scoliotic arc size	Probability of progression
Brooks	1975	134	Not specified	5.2%
Rogala	1978	603	Not specified	6.8%
Clarisse	1974	11O	10°-29°	35%
Fustier	1980	70	<30°	56%
Bunnell	1980	326	<30°->30°	20%-40%
Lonstein	1984	727	5°-29°	23%

It should be noted that deformations that have reached 45-50° progress most intensively during the growth period, but can also increase in patients who have finished growing.

The radiological features of progressive and non-progressive idiopathic scoliosis were studied by M.N. Mehta (1972) and, accordingly, are called the first and second signs of M.N. Mehta:

The first sign of M.N. Mehta reflects the probability of progression of scoliotic deformation depending on the value of the costovertebral angle, if the difference in the values of the costovertebral angles a and b, measured at the level of the apical vertebra on the convex and concave side of the scoliotic arc, does not exceed 20°, the probability of progression of the deformation is 15-20%; if this difference exceeds 20°, progression of the deformation is noted in 80% of cases;

The second sign of M.N. Mehta determines the probability of progression of scoliotic deformation depending on the projection ratio of the head of the rib and the body of the apical vertebra on the convex side of the arc. The author identifies two phases of the sign:

• phase 1 - the heads of the ribs are projected laterally from the body of the apical vertebra: the probability of progression is low;
• Phase 2 - the head of the rib on the convex side of the scoliotic deformity is superimposed on the body of the apical vertebra: the probability of progression is high.

The second sign of MHMehta actually characterizes the severity of torsional changes in the apical vertebrae.

Later studies, including ours, have established that the presence of II-IV degrees of torsion, measured using the pedicle method, has an unfavorable prognosis with regard to the progression of scoliotic curves in adolescents who have not yet completed their growth.

Some known prognostic signs of scoliosis progression are currently of historical interest, as they have not found wide practical application or are not reliable enough to predict the course of deformation. One of them is the definition of the Harrington stability zone, located between two perpendiculars restored through the roots of the L5 vertebra arches to the line connecting the wings of the iliac bones. If the greater part of the apical vertebra of the lumbar arch is located inside this zone, the deformation is considered stable, if outside it - progressive. The concept of the "stability zone" was also used by the author to determine the length of the posterior spondylodesis zone and to determine the supporting arches of the vertebrae, which, when installing a distractor, should be inside the stability zone.

Of historical interest is also the sign of scoliosis progression described by I.I. Kon, but which has not received statistical confirmation.

In conclusion of the section devoted to the prediction of scoliotic deformations, we should note the following: absolutely objective evidence of the progression of spinal deformation is radiographic confirmation of the growth of the scoliotic arc. In cases where this is possible, we consider it necessary to predict the possible course of deformation with a certain degree of reliability already during the initial examination and inform the patient and his parents about it. Of particular importance in the dynamic observation of a patient with scoliotic deformation is the frequency (multiplicity) of patient examinations and control radiographs.

In case of prognostically favorable spinal deformities, the patient should be examined by an orthopedist or vertebrologist every 6 months, and an X-ray examination should be performed once a year. If the risk of scoliosis progression is high enough, or if parents or the patient themselves subjectively note an increase in the deformity, a specialist examination and X-ray examination should be performed every 4-6 months.

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