Congenital scoliosis: causes, symptoms, diagnosis, treatment

Scoliosis is a lateral curvature of the spinal column, combined with its torsion.

ICD-10 code

• M41. Scoliosis.
• Q76.3 Congenital scoliosis due to malformation of bone.

The surgeon usually faces three problems: identification of the congenital anomaly, the prospects for progression of the deformity, and treatment of scoliosis.

What causes congenital scoliosis?

Scoliosis is most often encountered due to anomalies in the formation of vertebrae. Such anomalies include wedge-shaped vertebrae and hemivertebrae.

The progression of spinal deformity depends on such factors as the type of anomaly, the location and number of abnormal vertebrae, the presence (or absence) of their fusion with adjacent vertebrae.

If the body of a wedge-shaped vertebra (hemivertebra) is separated from the adjacent one by a normally developed intervertebral disc, then both vertebrae have growth plates and, therefore, grow at the same rate. The fundamental difference between them is that the wedge-shaped vertebra is initially deformed, moreover, due to the Hueler-Folkmann law, the degree of deformation gradually increases. The presence of growth plates leads to the progression of the deformation of the spine as a whole and thus becomes the most important prognostic factor. Such a vertebra was defined by I.A. Movshovich as active. If the abnormal vertebra merges with one or both adjacent vertebrae, the progression of the deformation becomes benign. Such a wedge-shaped vertebra (hemivertebra) is defined by I.A. Movshovich as inactive.

The second important factor in the progression of the deformation is the number of abnormal vertebrae. If there are two or more wedge-shaped vertebrae (hemivertebrae) and all of them are located on one side, this is a prognostically unfavorable sign. If the abnormal vertebrae are located on opposite sides of the spine and are separated by at least one normal vertebra, the prognosis for the progression of scoliosis can be quite favorable. Such vertebrae are called alternating.

Congenital scoliosis of the second group - deformations on the basis of anomaly of segmentation of the spine. These disorders occur at any level, but most often in the thoracic spine. The block can form at any length - both in the frontal and horizontal plane. The rate of progression of scoliosis on the basis of anomalies of segmentation depends on the number of segments involved in the block zone and the preservation of growth plates on the convex side of the deformation.

Congenital scoliosis in its most severe form is type III deformation according to the Winter classification (mixed anomalies). This is scoliosis, the development and progression of which is based on one-sided blocking of the vertebrae in the presence of one or more wedge-shaped vertebrae on the opposite side (at the level of the block). The combination of two types of scoliosis anomalies mutually enhances the effect of each of them, which leads to catastrophic consequences already at an early age.

A separate, although small, group is congenital scoliosis due to multiple developmental anomalies affecting almost the entire spine. Such patients sometimes do not have a single normally formed vertebra.

Associated anomalies are very common. These include anomalies of the head and neck (cleft palate and upper lip, ear deformity, mandible deformity, absence of the epiglottis, deficiency of the VII and VIII pairs of cranial nerves), trunk (congenital heart defects, sternum deformity, absence of a lung, tracheoesophageal fistula, esophageal stricture), urinary system, and limbs.

How is congenital scoliosis treated?

Conservative treatment of scoliosis

Congenital scoliosis cannot be treated with conservative methods.

[ 1 ], [ 2 ], [ 3 ]

Surgical treatment of scoliosis

Indications for surgical intervention in congenital scoliosis should be considered in terms of the severity of the existing deformation and the prospects for its further progression.

The operation should be performed at the age when the indications for intervention are not in doubt, even if it is a very early age (2-5 years). Moreover, many surgeons are convinced that scoliosis treatment should begin at the age of 3.

Orthopedic literature contains references to a wide variety of numerous interventions that can change the natural course of congenital scoliotic deformity. Treatment of scoliosis depends, among other things, on the experience of the surgeon and the equipment of the clinic. There is no universal method, but in recent decades, most orthopedists have been inclined to the need for anterior-posterior stabilization of the spinal column (360 fusion).

Posterior spondylodesis without instrumentation

Posterior spondylodesis without instrumentation is the best method for deformities that are clearly progressive or of such a nature that progression is inevitable, but at the same time are so rigid that correction seems unrealistic. A classic example is a unilateral non-segmented block.

The basic principles of surgical intervention are as follows.

• The spondylodesis area should include the entire arc of curvature plus one segment cranially and caudally,
• The posterior sections of the vertebrae must be exposed as widely as possible, that is, up to the tops of the transverse processes.
• The formation of the bone bed must be meticulous and include resection of the articular facets and complete decortication of the posterior vertebral structures.
• It is necessary to use a large number of grafts.

Formation of the block requires postoperative external immobilization. The use of corrective corsets such as Milwaukee or corsets with halotraction (for cervicothoracic deformities) for this purpose allows achieving some correction of scoliosis. In addition, the use of such devices helps to normalize the balance of the trunk and form a bone block in conditions close to normal from the point of view of the biomechanics of the spinal column.

Lonstein et al. emphasize that the results of posterior fusion with bel instrumentation are excellent as long as the surgeon understands that significant correction is not the primary goal. The primary goal is stabilization, i.e., prevention of progression.

Many surgeons claim that spondylodesis cannot be performed on a small child, as it limits his growth. It is true that the formed block of vertebrae does not grow in length with the growth of the patient or grows slower than normal, but it must be remembered that with congenital scoliosis, the blocked area has no growth potential. It is nature that shortens the spine, not the surgeon; the child will have a longer torso after early spondylodesis if this operation is not postponed.

Posterior spondylodesis with instrumentation

Supplementation of posterior spondylodesis with metal implants aims to achieve greater stabilization of the spine, which reduces dependence on the quality of external immobilization, and also to obtain a more significant correction of the deformity. The use of Harrington distractors for this purpose is associated with an increased risk of developing neurological complications. The use of CDI or its analogues is much more attractive. But any intervention using metal implants requires a thorough preoperative examination of the contents of the spinal canal, as well as intraoperative monitoring of the spinal cord.

Anteroposterior spinal fusion

This intervention is optimal in terms of stopping the progression of congenital scoliosis. The formation of a circular (360) bone block is accompanied by the destruction of growth plates on the convex side of the arc and balances both sides of the spine in terms of growth potential and, accordingly, increasing deformation. Performing anterior spondylodesis in patients with congenital scoliosis has its own characteristics.

• The first feature is the need to identify abnormally developed and located intervertebral discs.
• The second feature is the abnormal location and branching of segmental vessels.

It is advisable to perform ventral spondylodesis immediately before dorsal spondylodesis, that is, during the same anesthesia.

[ 4 ], [ 5 ], [ 6 ]

Anteroposterior epiphysiospondylodesis

The fundamental difference from the previous intervention is that epiphysiospondylodesis does not simply block the spine at a certain length, but, by stopping the growth of bone tissue on the convex side of the deformity, preserves it on the concave side.

Epiphysiospondylodesis is indicated for young children aged 1 to 5 years if the progression of the deformity is documented, the arc length is small, the growth potential on the concave side is preserved, and the deformity itself appears to be purely scoliotic - without pronounced kyphosis or lordosis. The operation may also be effective in patients over 5 years of age.

Dubousset et al. proposed a scheme for planning the epiphysiospondylodesis operation depending on the localization of the anomaly and its nature. Each vertebra can be imagined as a cube consisting of four parts (quadrants), each of which grows symmetrically around the spinal canal. If the growth processes are asymmetrical, which is what happens in the case of congenital deformation of the spine, it is necessary to determine in advance which zones need to be blocked to restore the lost symmetry. Using a four-quadrant scheme allows you to decide where exactly (in the horizontal plane) the bone block should be formed.

The second component of the Dubousset scheme is determining the extent of spondylodesis along the length of the spinal column. If epiphysio-spondylodesis is performed only at the level of the abnormal vertebra, this will only lead to a stabilizing effect. However, if it is necessary to achieve correction of the deformation during the ongoing growth of the spine, the epiphysio-spondylodesis zone must include the above- and below-lying segments.

[ 7 ], [ 8 ], [ 9 ], [ 10 ], [ 11 ], [ 12 ]

Excision of a hemivertebra

The first operation of this kind was described in 1928 by Royle, and was subsequently used by many surgeons. In essence, excision is a vertebrotomy on the convex side of the curvature; if the operation does not result in the formation of a block at the level of vertebrotomy, it can be considered unsuccessful. Excision of a hemivertebra is associated with a real risk of developing neurological complications, since the lumen of the spinal canal must be opened from the front and back. Indication for surgery is spinal deformity due to a single hemivertebra. Experience shows that performing it without the use of metal structures that provide compression on the convex side of the arch and thereby closing the post-resection wedge-shaped defect often leads to non-union of the bone surfaces and progression of the deformity. The optimal age for performing the operation is up to 3 years, although it can be quite effective at an older age. In lumbar scoliosis, epiphysiospondylodesis is performed in front and behind on the convex side of the deformity, covering the level of the hemivertebra and two adjacent ones - cranially and caudally; in the thoracic and thoracolumbar spine, due to the risk of the above-mentioned complications, two vertebral segments above and below the hemivertebra should be included in the instrumentation zone.

The first stage of the intervention is the removal of the body of the hemivertebra. Access depends on the localization of the anomaly. The body is removed completely to the base of the arch root. Along with the vertebral body, adjacent intervertebral discs and growth plates of the bodies of adjacent vertebrae are removed. E.V. Ulrich recommends using a localized arch root to facilitate identification of the posterior sections of the abnormal vertebra during the second stage of the intervention. For this purpose, a 6-8 cm long Kirschner wire is inserted into the center of the base of the arch root and passed in the dorsal direction through the soft tissues and skin of the back. This gives the surgeon a clear and reliable reference point, allowing him to reduce the time spent searching for the necessary hemivertebra and not expand the access unnecessarily. Autografts are placed in place of the resected hemivertebra, the wound is sutured layer by layer.

The second stage is correction of the deformity and posterior epiphysiolysis. The approach is median. The posterior sections of the vertebrae are isolated subperiosteally on the convex side of the arch over three segments. The posterior structures of the abnormal vertebra are removed, after which, in fact, a defect is formed with its apex facing the concavity of the deformity. Two CDI hooks are inserted behind the semi-arches of the vertebrae located on the borders of this defect. The length of the rod should be less than the distance between the hooks before compression. The rod is inserted into the hooks, the nut is tightened on one of the hooks, the hooks are brought together with a compressive force using a contractor, and as a result, the wedge-shaped post-resection defect is eliminated and the spinal deformity is corrected. The nut is tightened on the second hook. The operation is completed by placing autografts on the convex side of the deformity next to the instrumentation.

[ 13 ], [ 14 ], [ 15 ], [ 16 ]

Staged distractions without spondylodesis

This type of surgical treatment is designed for malignantly progressive forms of infantile and juvenile idiopathic scoliosis. Its use in congenital deformities is limited to fairly rare forms characterized by multiple anomalies along the entire length of the thoracic and lumbar spine and in combination with the young age of the patient and sufficient mobility of the deformity.

One-stage resection of a hemivertebra and correction of deformity with segmental instrumentation (Shono operations)

Indications: adolescent scoliosis due to single hemivertebrae of the thoracic and thoracolumbar localization, which do not require extension of spondylodesis to the lower lumbar spine.

The patient is placed in the prone position. The posterior sections of the vertebrae are exposed to the apices of the transverse processes, and the hemivertebra is identified. Its spinous process, arch, and articular facets are resected while preserving the root of the arch and transverse process. These two structures are resected only if the spinal cord is directly visualized (in the thoracic region, the rib corresponding to the hemivertebra is excised for 3 cm). Resection of the body of the hemivertebra begins at the base of the root of the arch and continues centrally to the anterior and ventral endplates. There is usually no need to remove them, since after applying a compressive force on the convex side of the deformity, they break and crumple like an empty eggshell. It is necessary to remove the tissue of the intervertebral discs and endplates on both sides of the hemivertebra. Resection of the root of the arch and the body of the hemivertebra is facilitated by the fact that the clearly visible spinal cord is displaced towards the concavity of the deformity.

The next stage is the implantation of screws and hooks in accordance with the preoperative planning. It is necessary to provide compression along the convex side of the deformity and distraction along the concave side. Before the correction, it is necessary to place autografts in the form of shavings between the adjacent vertebrae in the defect formed after the resection, otherwise voids may remain. The first rod to be implanted is on the convex side of the arch, having previously bent it in accordance with the normal sagittal contour of the spine. On this rod, hooks or screws develop a compressive force to crush the endplates and close the triangular post-resection defect. At the same time, scoliosis and local kyphosis are corrected. The second rod is implanted on the concave side of the arch. Distraction, however, should be dosed to avoid excessive tension on the spinal cord. The main role of the second rod is additional stabilization. Posterior spondylodesis with autobone is performed along the entire length of the curvature arc. Bed rest must be observed for 1-2 days. Immobilization with a corset is indicated for 3 months,

Surgeries for segmentation disorders

Scoliosis in young children is treated by performing epiphysiospondylodesis. The side and length of the spondylodesis are determined in accordance with the Dubousset scheme. In older children and adolescents, surgical tactics, among other things, are dictated by the presence or absence of compensatory counter-curvature. Optimally, anteroposterior spondylodesis is performed using CDI, which allows for a significant elimination of compensatory counter-curvature and thereby normalizes the balance of the trunk. In the most severe advanced cases, including in adult patients, a wedge osteotomy of the block can be performed. During the operation, the spine is purposefully destabilized to achieve the necessary correction. The risk of complications increases proportionally to the correction achieved. Lost stability must be immediately restored on the operating table.