Spinal cord injuries, trauma and back pain

It is hardly possible to overestimate the place of spinal trauma in the overall structure of traumatic injuries, the number of which is steadily growing along with the rise in living standards, the development of modern transport, the increase in the number of military conflicts, etc., etc. We will provide just some statistical information.

According to V.P. Bersnev et al. (1998), 300-330 people suffer combined spinal and spinal cord injuries in St. Petersburg every year. 5-50% of patients with spinal injuries have multiple injuries to the long tubular bones and skull, and 20% have abdominal injuries. 80% of patients with traumatic spinal cord injuries are under 40 years of age. It is characteristic that mortality in spinal injuries in 50% of cases is associated not with the initial severity of the injury, but with its untimely diagnosis and inadequate management at the prehospital and hospital stages. It should be noted that the information provided does not apply to cervical spine injuries, which are accompanied by the most severe complications and information about which is provided in the last chapter of this publication.

We were unable to find any all-Russian statistics on vertebral trauma. However, according to official sources in the USA, spinal injuries are observed annually in 18,000-38,000 people, of which an average of 4,700 cases (i.e. about 20%) are accompanied by paraplegia.

The classification of spinal injuries is usually based on one or another feature, which is considered by the authors as the leading one in determining the nature or severity of the injury. Thus, according to the duration of the damaging factor, acute injuries are distinguished, which occur immediately at the moment of injury, and chronic injuries, which develop with repeated action of the damaging factor (for example, with unstable fractures). Taking into account the time elapsed from the moment of injury, the consequences of the injury are also distinguished.

Depending on the involvement of tissues adjacent to the spine, primarily the spinal cord, uncomplicated, complicated and combined injuries are distinguished. In uncomplicated injuries, damage is limited to only bone and soft tissue structures that directly form the spine. In complicated injuries, tissues and organs adjacent to the spine are damaged by bone fragments of the vertebrae. Combined injuries are characterized by simultaneous damage to the spine and other organs by the direct action of the damaging factor.

According to the mechanism of the damaging action, flexion, extension, rotation, dissecting injuries and injuries arising from axial pressure are distinguished (Bohler L., 1956). E.A. Nicoll (1949) and F.W. Holdsworth (1970) based the classification of spinal injuries on the condition of the fixing ligamentous apparatus and the violation of the mechanical stability of the spine that occurs (or does not occur) when it is damaged. Accordingly, the authors distinguished stable injuries (simple anterior compression fractures, burst fractures and extension injuries) and unstable ones, which included distraction and rotational dislocations, fracture-dislocations, and dissecting fractures of the vertebrae. The principle of determining the stability of the injury was later used in the AO/ASIF (see abbreviations) classification of spinal injuries, which is quite widely used at present. This classification is given below.

All of the above classification principles are included in one form or another in the summary classifications of spinal injuries. We present only three of them, which are currently most widely used in our country and abroad. The reader is given the opportunity to independently choose the scheme that is most convenient for practical use.

The combined classification of G.P. Saldun (1983) includes eight main groups and 46 signs of damage to the vertebral segment, according to which injuries are divided as follows.

By localization of the lesion:

1. cervical spine,
2. thoracic region,
3. lower thoracic and lumbar regions,
4. sacrococcygeal region.

By the nature and degree of damage to the spinal cord and its elements:

1. Uncomplicated fractures.
2. Aggravated fractures:
   1. spinal cord rupture (anatomical break),
   2. spinal cord compression,
   3. spinal cord contusion,
   4. compression or damage to spinal cord elements (roots).

By the mechanism of damage:

1. Compression fractures.
2. Compression-flexion fractures.
3. Flexion fractures.
4. Compression-rotational fractures.
5. Rotational injuries.
6. Extension fractures.

According to the degree of wedge-shaped deformation of the vertebra:

1. Marginal fractures.
2. Deformation up to 1/4 of the normal height of the vertebral body.
3. Deformation up to 1/3 of the height.
4. Deformation up to 1/2 height.
5. Deformation more than 1/2 of the height.

By the nature of the vertebral damage:

1. Penetrating fractures:
   1. with neurological symptoms,
   2. without neurological symptoms.
2. Vertical fractures.
3. Horizontal fractures
4. Comminuted ("explosive") fractures,
5. Multiple vertebral fractures:
   1. adjacent,
   2. non-adjacent,
   3. combined with damage to other areas of the musculoskeletal system;
6. Fractures of the arches:
   1. on one side (with offset, without offset),
   2. on both sides (with offset, without offset).
7. Fractures of the articular processes:
   1. on one side (with offset, without offset),
   2. on both sides (with offset, without offset),
   3. adjacent vertebrae.
8. Complete rupture of the posterior support complex
9. Damage (rupture) of the ligamentous apparatus
10. Fractures and dislocations:
    1. full,
    2. incomplete,
    3. burdened,
    4. unencumbered
11. Fractures of the spinous processes, fractures of the transverse processes (single, multiple)

By the nature of stability.

1. Stable damage:
   1. Compression fractures of the vertebral bodies are non-penetrating, without signs of damage to the posterior support complex, with a wedge-shaped deformation of up to 1/3.
   2. Extension fractures
2. Conditionally stable injuries.
   1. Uncomplicated compression fractures of the vertebral bodies with wedge-shaped deformation up to 1/2 without signs of damage to the posterior support complex.
   2. Multiple fractures of vertebral bodies with a total wedge shape of up to 1/2 of one of them. Penetrating fractures with persistent pain syndrome.
3. Unstable damage.
   1. Vertebral fractures with wedge-shaped deformation of 1/2 or more, aggravated and unaggravated.
   2. Less pronounced wedge-shaped deformity, but with signs of damage to the posterior support complex or deformation of the spinal canal.
   3. Fractures and dislocations, aggravated and unaggravated.
   4. Multiple fractures of the vertebrae with a total wedge-shapedness of more than 1/2 of one of them.
   5. Comminuted, vertical and horizontal fractures.
   6. Complicated and uncomplicated fractures after laminectomy.

Vertebral fractures in the elderly.

Combined fractures (with damage to internal organs, brain, etc.).

The classification of spinal injuries by F. Denis (1983) is based on the theory of "three columns" developed by him. In contrast to the theory of two columns proposed by F. Holdsworth (1970), the boundary between which was the frontal plane passing along the posterior longitudinal ligament, F. Denis identified a middle column, which is directly adjacent to the spinal canal. According to Denis, the anterior column of the spine consists of the anterior longitudinal ligament, the anterior parts of the vertebral bodies and the intervertebral discs; the middle column consists of the posterior halves of the vertebral bodies adjacent to the spinal canal, the intervertebral discs and the posterior longitudinal ligament; the posterior column is formed by the arches, transverse, articular and spinous processes, as well as the posterior muscular-ligamentous-capsular apparatus of the spine.

Clinical manifestations and severity of spinal injury according to F. Denis are determined by:

• mechanism of damage,
• damage zone (damaged column) and
• stability (or instability) of the damaged segment.

Moreover, the concept of “instability” has a dual interpretation and includes mechanical and neurological components.

Mechanical instability (the author also uses the term “first-degree instability” to describe it) is characterized by pathological mobility of the spine (or the threat of its occurrence), which occurs at the level of the damaged segment directly at the moment of injury, or by the progression of spinal deformation in the late periods after injury (the so-called “dynamic” or delayed instability).

Neurological instability (or second-degree instability) is damage or the theoretical possibility of damage to the spinal cord and its elements by bone fragments of damaged vertebrae directly during the injury or with its inadequate management.

The combination of mechanical and neurological instability is described by the author as "grade 3 instability."

It should be noted that F. Denis uses the term “potential” instability to denote theoretically possible post-traumatic instability of the spine; in Russian literature, this type of instability is described as “threatening”.

Since the concept of “spinal instability” is interpreted differently by different authors, it is appropriate to cite the classical triad of clinical signs of chronic post-traumatic spinal instability given by I. Posner et al. (1981):

1. dynamic (progressive and/or transient) neurological disorders;
2. pain;
3. progressive deformation of the spine.

According to the classification of F. Denis, a distinction is made between “minor” vertebral fractures, which include isolated damage to the posterior vertebral column, and “large” fractures, which are accompanied by mandatory damage to the anterior and/or middle columns of the spine.

"Minor" vertebral fractures include fractures of the articular and transverse processes, spinous process, and fracture of the interarticular part of the arch. These fractures are often accompanied by damage to the ligamentous apparatus of the posterior column of the spine. Isolated "minor" fractures are mechanically and neurologically stable in the vast majority of cases, with the exception of neurologically unstable "pressed into the canal" fractures of the arches. In the long term, isolated "minor" spinal injuries can cause chronic pain syndromes, which are usually associated with the absence of fusion of bone fragments, the formation of pseudoarthrosis, or inadequate healing of the injured fixing muscular-ligamentous apparatus with the development of segmental hypermobility.

"Major" spinal injuries include injuries to the vertebral bodies and intervertebral discs that make up the anterior and middle columns, including any combinations of these with damage to the elements of the posterior column. According to the nature of bone injuries assessed radiologically, as well as according to CT and/or MPT data, F. Denis identified four variants, and within each of them, several types of vertebral injuries (letter designations of injury types are given by us in accordance with the author's description):

[ 1 ], [ 2 ]

Compression fractures of the vertebral bodies

The mechanism of injury is anterior and/or lateral flexion.

The damage zone is the anterior column of the spine. The posterior column and the part of the middle column adjacent to the spinal canal always remain intact in this type of damage.

Characteristic anatomical, radiological and clinical signs of injury: the integrity of the spinal canal ring is not violated, the interpedicular distance is not changed, a slight expansion of the interosseous space is possible. The injuries are always mechanically and neurologically stable. With severe compression of the vertebral bodies, delayed mechanical instability is possible, accompanied by pain syndrome and increasing deformation of the spine. The following types of compression fractures of the vertebrae are distinguished:

• A - vertical fracture of the vertebral body passing through the superior and inferior endplates;
• B - fracture of the upper (cranial) part of the vertebral body with damage to the upper endplate;
• C - fracture of the lower (caudal) part of the vertebral body with damage to the lower endplate;
• D - central ("horizontal") fracture of the body, typical for osteoporotic vertebrae.

The author notes that compression fractures of the vertebral bodies can be asymmetrical, i.e. accompanied by lateral compression of the vertebral body.

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Blast fractures of the vertebrae

The mechanism of injury is a blow directed along the vertical axis of the spine, the so-called axial trauma.

Damage zone - middle column of the spine, possibly combined with damage to the anterior column.

A characteristic anatomical and radial sign is an increase in the interpedicular distance and the anteroposterior size of the vertebral body.

The following types of burst fractures of the vertebrae are distinguished:

• A - a fracture passing through both endplates (typical for lumbar vertebrae);
• B - fracture of the superior endplate;
• C - fracture of the inferior endplate,
• D - rotational fracture (the most unstable of burst fractures) - rotational displacement of the injured fragments is observed in the presence of all the typical radiographic signs of a fracture-dislocation, but without damage to the intervertebral joints, i.e. without a true dislocation of the vertebrae;
• Type E - a burst fracture with lateral flexion (accompanied by a fracture of the lateral sections and displacement of the lateral fragments of the vertebra into the spinal canal).

The most informative data for diagnosing burst fractures are CT data, including in combination with myelography, and transverse MRI slices, which often reveal not only damage to the middle column of the spine and displacement of a fragment of the vertebral body into the spinal canal, but also splitting of the vertebral arch along its anterior surface, which is typical for this type of injury. The injury is mechanically conditionally stable, and delayed (dynamic) instability associated with impaired support of the vertebrae may develop. A characteristic feature of burst fractures of the vertebral bodies is always their neurological instability, which occurs even in the absence of signs of traumatic myelopathy. In burst fractures of the thoracic vertebrae, the clinical picture of compression myelopathy is observed in almost 70% of cases, in fractures of the lumbar vertebrae - in slightly more than 20%, which is associated with the anatomical features of the spinal cord.

F. Denis points out three possible causes of neurological disorders in burst fractures:

1. compression of the spinal cord by a fragment of the vertebral body,
2. narrowing of the nerve root canals with mechanical compression of the roots themselves and
3. pinching of the spinal nerves in the split anterior surface of the vertebral arch.

The latter type of injury is typical for the lumbar spine, in which the elements of the equine tail occupy a predominantly dorsal position within the spinal canal. Understanding the various mechanisms of neurological complications of burst fractures and their accurate diagnosis is of particular importance when choosing surgical treatment tactics: if, when the spinal cord is compressed by a fragment of the vertebral body, its anterior decompression is absolutely indicated, then the infringement of the nerve roots in the split arch dictates the need for revision of the posterior sections of the spinal canal.

Seat-belt damage - damage of the "seat belt" type.

The mechanism of injury is a sharp bending with axial traction of the upper and lower fragments of the spine with its "central" section fixed (the so-called flexion-distraction mechanism). A similar mechanism is typical for car accidents: when the car brakes sharply and the central section of the body is fixed with seat belts (which is reflected in the name), its upper and lower halves continue to move forward by inertia.

Damage zone - elements of the posterior and middle columns of the spine are always damaged, damage to the anterior column is possible. The anterior longitudinal ligament and the anterior part of the fibrous ring of the intervertebral disc are never damaged.

Characteristic anatomical, radiological and clinical signs of injury. In cases where the line of injury passes through the bone elements of the vertebrae, fractures of the elements of the posterior column are revealed radiologically, and fragments of the bodies adjacent to the posterior sections of the intervertebral discs may be torn off. The size of the interosseous spaces may expand.

The following types of seat-belt damage are distinguished:

• A - single-level intervertebral injury, accompanied by rupture of the ligament-articular apparatus and the posterior part of the intervertebral disc;
• B - single-level transvertebral injury or Chance fracture - horizontal fracture of the posterior, middle and anterior columns;
• C - two-level injury with a fracture of the arch and damage to the fibrous part of the middle column;
• D - two-level injury with a fracture of the arch and damage to the bony part of the middle column.

Seat-belt injuries are always mechanically unstable, and instability is most pronounced in cases of injury to the fibrous and muscular parts of the posterior and middle columns - interosseous ligaments, muscles, intervertebral discs. That is why the term "damage" is used for this type of injury, not "fracture". In some types of injury (seat-belt injuries type A), radiographs may completely lack signs of damage to the bone structures of the spine, which leads to erroneous interpretation of radiographs. Undiagnosed soft tissue injury is accompanied by incomplete healing of the fixing apparatus of the vertebrae, which leads to delayed instability and chronic pain syndrome. In the acute period of injury, the diagnosis can be more clearly established by magnetic resonance imaging: in the structures of the posterior column of the spine at the level of injury, an increase in the signal associated with local hemorrhage is always detected.

Seat-belt injuries are not accompanied by a violation of the vertebral-spinal relationships, and therefore are neurologically stable. However, this type of injury may be accompanied by the clinic of "ascending myelopathy", the pathogenesis of which is associated not with mechanical damage to nerve structures, but with traction myeloischemia: microcirculatory changes in the spinal cord are located above the spinal injury zone, which is clinically manifested by a discrepancy between the level of bone and neurological disorders.

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Vertebral fractures and dislocations

Mechanism of injury: combined action of forces - compression, extension, rotation and flexion.

Characteristic anatomical, radiological and clinical signs of injury. All three columns of the spine are injured, including possible damage to the anterior longitudinal ligament. This is the most unfavorable variant of spinal injuries, which are both mechanically and neurologically unstable. F. Denis identified the following types of fracture-dislocations of the vertebrae:

• A-flexion-rotation, in which it is possible to maintain normal relationships in one of the facet joints;
• B - "cutting" extension fracture-dislocation;
• C - flexion-distraction fracture with bilateral dislocation.

Based on the classification of F. Denis, an algorithm for diagnostics and tactics of management of spinal and spinal-spinal cord injuries was proposed, the widespread use of which, in our opinion, will allow doctors, on the one hand, to be more active in the use of modern methods of treating spinal injuries, and on the other - to approach the choice of surgical intervention more differentiated. It should be noted that in some cases of burst fractures not accompanied by neurological complications (which is more often observed in the lumbar region), it is possible to conduct conservative treatment with adequate reclining orthotics.

The AO/ASIF classification of spinal injuries is compiled in accordance with the UPC - Universal Classification of Fractures, which, in turn, is based on the determination of the mechanical instability of the injured skeletal section. According to the considered

According to the authors of the AO/ASIF classification, impacted fractures of the vertebral bodies (type AI) are always mechanically stable and require adequate conservative treatment. Splitting and burst injuries of the vertebral bodies, differing only in the number of bone fragments (types AII and AIII, respectively), are conditionally stable, since they heal poorly, which leads to an increase in kyphosis ("dynamic" instability) or late neurological complications.

Spinal injuries that occur with extension (type B) are in most cases mechanically unstable, and injuries with rotation (type C) are always mechanically unstable. At the current level of development of medical technologies, these types of injuries in the vast majority of cases are subject to surgical treatment, including in children.

Spinal trauma in children and adolescents has certain characteristics. Typical, but not the only possible for patients of this age group, is damage to the vertebral bodies by the type of compression fracture. The type of fracture is usually determined by the degree of decrease in the height of the vertebral body, primarily the height of its ventral or central sections. Compression fractures in children are classified by the severity of the injury.

Compression fractures of the spine in children.

Compression ratio	Radiographic characteristics (change in vertebral body height)
Grade I - minor compression	Reduction in the height of the ventral section by 2 mm Reduction of the height of the middle section by 1 mm
II degree - moderate compression	Reduction in the height of the ventral section by 2-5 mm, Reduction of the height of the middle section by 2 mm
III degree - significant compression	Decrease in the height of the ventral section by 4-6 mm Reduction of the height of the middle section by 2-3 mm
IV degree - severe compression	Decrease in the height of the ventral section by more than 5 mm Decrease in the height of the middle section by more than 3 mm

None of the degrees listed in the table, with the exception of some fractures with pronounced IV degree compression, exceed the severity of injuries corresponding to impacted fractures of group AI according to the AO/ASIF classification. Children with such fractures never need surgical treatment. IV degree fractures with pronounced compression, accompanied by delayed mechanical instability leading to the formation of kyphosis, can be subjected to surgical treatment in order to stabilize the spine and prevent the deformity from increasing. Other types of vertebral injuries, accompanied by trauma to the middle and posterior columns, occur in childhood much less frequently than compression fractures. In our opinion, with such injuries in children it is advisable not only to use one of the above classifications, but also to apply a more active treatment tactic - early surgical intervention aimed at eliminating the mechanical and neurological instability of the injury will ensure the best treatment outcome for this category of patients.

Gunshot wounds to the spine, the number of which, unfortunately, has been steadily increasing in recent years due to the spread of firearms and numerous local military conflicts, deserve special mention. The main classification feature of this type of injury is the relation of the wound canal to the bone structures of the vertebrae and the spinal canal. N.S. Kosinskaya identifies the following types of wounds:

1. penetrating wound - the wound channel crosses the spinal canal;
2. blind penetrating wound - the wound channel ends inside the spinal canal;
3. tangential wound - the course of the wound channel is accompanied by marginal damage to the walls of the spinal canal;
4. blind non-penetrating wound - only the bone elements of the vertebrae are damaged;
5. paravertebral wound - the wound channel passes through soft tissues without affecting the actual structures of the spine.