Congenital kyphosis

The peculiarity of congenital kyphosis forces one to consider this type of deformity of the spine separately. Traditionally, the congenital kyphosis group includes not only single-plane sagittal deformities or so-called sagittal deformities. "Pure" (English "rigue") kyphosis, but also kyphoscoliotic deformations with a leading kyphotic component. Almost all authors point out significant differences in the course of pure kyphosis and combined kyphoscoliosis and consider the presence of a scoliotic component as an element of compensation for a defect, which "saves" the body from the development of vertebro-spinal conflict and the development of myelopathy. The number of observations of "pure" congenital kyphosis in only rare, practically single works exceeds 30 cases.

At present, the "base" is the classification of congenital kyphosis by R. V. Winter (1973), without reference to which there is not a single publication on the problem under consideration. At present, earlier classification schemes are not used on their own. R. V. Winter identified three types of congenital kyphosis: type I kyphosis in the anomalies of the formation of vertebral bodies, type II kyphosis in anomalies of segmentation of vertebral bodies and type III kyphosis in mixed anomalies.

In the same 1973 Ya.L. Tsivyan also identified three variants of congenital kyphosis: kyphosis with a wedge-shaped (complete or supercomplete) vertebra, kyphosis during aplasia of the body (body) of the vertebra (vertebrae) and kyphosis when the vertebral bodies are congested.

The most detailed scheme of congenital kyphosis, based on the experience of the Novosibirsk Center for Spinal Pathology, is given by M.V. Mikhailovsky (1995). However, the author analyzes not so much the "pure" congenital kyphosis, but the congenital deformities of the spine, accompanied by the kyphotic component. That is why the classified group includes kyphoscoliosis, which account for up to 75% of all deformations considered by the author.

Classification of congenital deformities of the spine, accompanied by a kyphotic component.

Classification feature	Estimated parameters
I. Type of anomaly on the basis of which a deformation developed	Posterior (posterolateral) vertebrae (semi-vertebrae); Absence of the vertebral body (asomia); Microspondent; Concrement of vertebral bodies - partial or complete; Multiple anomalies; Mixed anomalies.
II. Deformation type	Kyphosis; Kyphoscoliosis.
III. Localization of the vertex of deformation	Cervicothoracic; Upper-thoracic; Medium-thoracic; Lower-thoracic; Thoracolumbar; Lumbar.
IV. The value of kyphotic deformation (degree of deformation)	I degree - up to 20 °; II century. - up to 55 °; III century. - up to 90 "; IVc. - over 90 °
V. Type of progressing deformation	Slowly progressing (up to 7 ° per year); Rapidly progressing (more than 7 ° per year).
VI. Age of primary detection of deformation	Infantile kyphosis; Kyphosis of small children; Kyphosis of adolescents and young men; Kyphosis of adults.
VII. The presence of the involvement of the contents of the vertebral canal	Kyphosis with neurological deficit; Kyphosis without neurological deficit
VIII. Associated anomalies of the spinal canal	Diastematomyelia; Diplomium studies; Dermoid cysts; Neuro-enteral cysts; Dermal sinuses; Fibrous constrictions; Anomalous spinal roots
IX. Concomitant anomalies of extrinsic localization	Anomalies of the cardiopulmonary system; Abnormalities of the thoracic and abdominal wall; Abnormalities of the urinary system; Anomalies of extremities
X. Secondary degenerative changes in the spine	None Revealed in the form: Osteochondrosis; Spondylosis; Spondyloarthrosis.

In our study, we managed to combine the experience of several world clinics - Twin Cities Spine Center, MN, USA, the State Pediatric Medical Academy and Phthisiopulmonology Research Institute, St. Petersburg, Russia, with the total number of patients with pure congenital kyphosis exceeding 80 people. This allowed us to detail the anatomical and radiological classification of RBWinter. In the course of the study, not only X-ray data were taken into account, but also the results of modern methods of radiation diagnostics, primarily magnetic resonance imaging. We are aware that in this form the above classification can not be considered complete. RB Winter described the effect of "spontaneous fusion" of vertebral bodies in the natural course of deformation, consisting in the concreteness of the vertebral bodies, which were initially visualized on the radiographs as segmented. Our experience has shown that in the MRI study of patients with spontaneous fusion, hypoplasia of the intervertebral discs in the form of a lack of luminescence of the pulpous nuclei was revealed even during the initial treatment. In the process of growth at the level of hypoplasia, a part of patients developed secondary degeneration with segmental instability of the spine, in others - true bone blockage.

Modified classification of pure congenital kyphosis

Type of kyphosis

Variants of deformation

I type - congenital kyphosis, caused by violation of the formation of vertebral bodies. II type - congenital kyphosis caused by a disruption of the segmentation of vertebral bodies III type - congenital kyphosis caused by mixed or undifferentiated developmental defects

A-agenesis of the body, B - hypogenesis of the body, the stored part of the body is less than 1/2 of its normal size, C - hypoplasia of the body, the stored part of the body is more than 1/2 its normal size. A - the true fusion of vertebral bodies, confirmed by roentgenologic and MRI data; B - hypogenesis of the disc: the presence of X-ray signs of the fusion of vertebral bodies while retaining the image of the disc according to MRI; the pulpous nucleus is hypoplastic; C - Hypoplasia of the disc: the disk is radiologically preserved, but lower in height; on an MRI the disk is devoid of a pulpous core.

The table contains data on the features of the spinal canal with various variants of congenital kyphosis and the frequency of secondary neurological complications (myelopathies) with them.

Sagittal stenosis of the spinal canal and frequency of neurological disorders in pure congenital kyphosis

Type of kyphosis	Mean value of narrowing of the spinal canal (%)	Frequency of neurological disorders (%)
1type:
IA	53	64
IB	36	Thirty
1C	13	17th
Type II	10	-
III type	25	36

If the relationship between the severity of the defect and the frequency of myelopathies in type I kyphoses seemed to us predictable, then the absence of neurologic disorders in type II kyphoses was unexpected, especially since there were patients with deformities of the fourth degree in this group. This disproves the opinion of the leading value of the magnitude of kyphotic deformation in the occurrence of neurologic complications of congenital kyphosis.

The data of the studies show that the main role in their development is played by stenoses of the spinal canal.

It should also be noted that in almost 20% of patients with congenital kyphosis, we identified various variants of myelodysplasia, and in almost half of cases its course was asymptomatic.

[1], [2], [3], [4], [5], [6]