Closed spinal injuries: causes, symptoms, diagnosis, treatment

In the occurrence of various spinal injuries, four main mechanisms of action of damaging violence should be distinguished: flexion, flexion-rotation, extension and compression. Each of these types of violence leads to a certain form of spinal injury, each of which can be classified as either stable or unstable injuries.

The concept of stable and unstable spinal fractures in traumatology was introduced by Nicoll in 1949 for the lumbar-thoracic spine, and in 1963 Holdsworth extended it to the entire spine.

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Causes of closed spinal injuries

To understand the further presentation, it is necessary to recall the basic (concepts about how individual vertebrae are connected into a single organ - the spine. With the exception of the first two vertebrae - the atlas and the axis, the bodies of all the underlying vertebrae are connected to each other by means of intervertebral discs - complex anatomical formations, one of the functions of which is to hold the body of one vertebra relative to the body of another. Thus, the stability of the anterior sections of the spine is ensured by the intervertebral discs or, more precisely, their fibrous rings, as well as the anterior and, to a lesser extent, the posterior longitudinal ligaments.

The posterior sections of the vertebrae are held in relation to each other by the postero-external intervertebral joints with their ligamentous and capsular apparatus, interspinous, supraspinous and yellow ligaments.

The stability of the vertebrae is mainly provided by these four structures: the postero-lateral intervertebral or, as they are also called, synovial joints, the interspinous, supraspinous and yellow ligaments, which we called the "posterior support complex" ("posterior ligament complex" according to Holdsworth). In all cases where the elements of the "posterior support complex" remain intact, the spinal injury remains stable. In all cases where the "posterior support complex" is damaged, the spinal injury is unstable.

Flexion mechanism. Flexion violence affecting the spine occurs with sudden significant one-time, forced bending of the human torso. This mechanism of violence occurs when heavy objects fall on the victim's shoulders, when falling from a height onto the buttocks or straightened yogis, etc. The breaking force is spent on overcoming the resistance of the extensor muscles and on the fracture of the vertebral body and is extinguished by this fracture. As a rule, with this mechanism of violence, the anatomical structures of the "posterior support complex" are not damaged. A typical compression wedge-shaped fracture of the vertebral body occurs, a fracture characteristic of the lumbar and lower thoracic localization. Since the structures of the "posterior support complex" are not damaged, this type of spinal injury should be classified as stable.

In some rare cases, when after a fracture of the vertebral body the damaging force continues to act and increases in magnitude, the ligaments of the "posterior support complex" may rupture. Then an unstable injury may occur.

In the cervical spine, where the anatomical structures of the “posterior support complex” are less strong, flexion force may result in flexion dislocations or fracture-dislocations, which are considered unstable injuries.

Extension mechanism. Until recent years, it was believed that extension injuries of the spine are extremely rare. Indeed, this mechanism of injury is rarely the cause of injuries to the thoracic and lumbar spine. However, it is common in the cervical spine. Approximately half of the injuries to the cervical spine occur as a result of extension violence.

Extension violence occurs with sudden, one-time hyperextension of the spine. With this mechanism of violence, the anatomical structures of the "posterior support complex" remain intact. There is either a fracture in the area of the roots of the arches, or, more often observed in the cervical spine, a rupture of the anterior longitudinal ligament and intervertebral disc or spongy substance of the vertebral body near the endplate, and an extension dislocation occurs. This injury is stable provided that the flexion position is maintained. If such a victim is treated with hyperextension, then irreparable harm can be caused to him. Extension injuries to the cervical spine often occur in motorists and divers when the head was in an extension position at the moment of impact with the bottom of the river.

Flexion-rotation mechanism. When exposed to flexion-rotation force or pure rotation, as a rule, damage to the anatomical structures of the "posterior support complex" occurs. If only the ligaments are damaged, which is more often observed in the cervical region, a pure dislocation occurs: if the articular processes and the anterior sections of the spine are simultaneously broken, a fracture-dislocation occurs. Both dislocations and fracture-dislocations belong to the category of unstable injuries. In their pure form, dislocations most often occur in the cervical spine, much less often in the lumbar region, and never occur in the thoracic region, which has an additional rigid attachment in the form of the rib cage.

The classic place for fracture-dislocations to occur is the lumbar and lumbar-thoracic spine. They are not so rare in the cervical spine and extremely rare in the thoracic spine. Flexion-rotational violence occurs when a weight falls on the area of one shoulder or scapula, when it acts asymmetrically and not only bends, but also rotates the spine around its vertical axis. This mechanism of violence often occurs in train and car accidents. Very often, such fractures are combined with damage to the contents of the spinal canal.

Compression mechanism. The compression mechanism of violence consists in the fact that the breaking force acts along a vertical line applied to the vertebral bodies. Such a mechanism of violence is characteristic only of the cervical and lumbar spine, the bodies of which in a certain position can be located strictly along a vertical line. The normal position for the cervical and lumbar spine is physiological lordosis. In a position of slight flexion, the cervical or lumbar spine straightens, lordosis is eliminated, and the vertebral bodies are located along a vertical line. When at this moment violence acts vertically on the vertebral bodies, a compression comminuted fracture of the vertebral body occurs. With such damage, the structures of the "posterior support complex" remain intact, which is why this type of damage is classified as stable.

The mechanism of this fracture was studied in detail and described by Roaf in 1960. In this case, severe damage to the spinal cord and its elements often occurs due to the posterior fragment of the broken vertebra displacing towards the spinal canal.

These are the four main mechanisms of spinal injury that determine the nature of each given spinal injury.

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Symptoms of a closed spinal injury

Symptoms of spinal injury should reflect the degree of stability of the existing injury, the presence or absence of complications from the spinal cord or its elements and the specific clinical form of spinal injury. A detailed clinical diagnosis can be established based on a detailed clarification of the circumstances of the injury and the material cause that caused it, clarification of the place of its application and the nature of the possible impact, data from an objective examination and survey and, finally, high-quality spondylograms in at least two projections - anterior and lateral.

However, when providing first aid to the victim at the scene of the incident, it is important to know at least approximately whether the injury is stable or unstable. This is important to know because transporting a victim with an unstable injury is more responsible and requires taking measures to exclude the possibility of additional or secondary damage to the contents of the spinal canal. The doctor can suspect an unstable injury based on the history and examination of the victim. The presence of swelling, traces of a bruise in the form of abrasions and bruises in the interscapular region allows one to think about a purely flexion mechanism, the presence of bruises and abrasions in the area of one shoulder or scapula - about a flexion-rotation mechanism, etc. A significant increase in the interspinous space allows one to think about the possibility of a rupture of the supraspinous and interspinous ligaments. An increase in the interspinous space and the broken lines of the spinous processes in the form of a bayonet make it possible to consider the suspicion of an unstable injury reliable. The fall of a weight on a slightly bent head allows one to think about a compression comminuted fracture of the body of the cervical vertebra, bruises and abrasions in the diver's back of the head - about a flexion injury, in the forehead and face - about an extension injury.

The final clinical diagnosis is formulated after a detailed examination of the victim and is an effective starting point for choosing the most rational and appropriate method of treatment.

Treatment of closed spinal injury

Surgical interventions on the spine in case of its injuries and their consequences have a number of specific features. These features are caused by the uniqueness of the spinal column as an organ and the multifaceted and responsible role it plays in human life, as well as its location in the human body. All this obliges the doctor who decides to perform surgical intervention on the cervical, thoracic or lumbar spine to know well, perfectly, the normal and pathological anatomy of the spine, the topographic-anatomical relationships of the spine with the surrounding formations, and to be able to navigate them. When invading the spine, the surgeon must be ready to eliminate possible complications due to previously occurring or occurring during the operation damage to the paravertebral formations.

Situated over a considerable distance in the human body, the spine is intimately in contact with the median structures of the neck, the posterior mediastinum and retroperitoneal space, the organs of the chest and abdominal cavity. When using anterior surgical approaches to the spine, the surgeon inevitably comes into contact with all of the above-mentioned structures that can be damaged during surgery. All this requires the surgeon operating on the spine to have perfect command of the surgery of the chest and abdominal cavities, surgery of the neck organs, vascular surgery and elements of neurosurgery.

Many surgical interventions on the spine are only possible under endotracheal anesthesia. A well-established anesthesiology service is an indispensable condition for surgical interventions on the damaged spine. An equally important and mandatory condition is the ability to begin immediate intensive care and resuscitation in the event of severe shock or blood loss. Timely and complete replenishment of blood loss during surgery requires a sufficient supply of preserved blood. Finally, surgical interventions on the damaged spine require special equipment and facilities.

Indications and contraindications. The use of surgical treatment methods is indicated in the following cases.

1. Cervical spine injuries:
   1. ) all unstable injuries (dislocations, fractures, dislocations), especially if they are combined with damage to the contents of the spinal canal. In these injuries, we consider surgical treatment methods to be less dangerous for the victim. They allow for reliable internal immobilization at the site of the former injury and transform unstable injury into stable; prevent subsequent occurrence and development of degenerative processes in the area of the intervertebral discs at the level of the former injury and in this sense are not only purely therapeutic, but also therapeutic and prophylactic; significantly facilitate patient care and make the patient mobile. They reduce the time the victim spends in bed and in hospital;
   2. compression comminuted fractures of the cervical vertebrae;
   3. all types of injuries to the cervical spine, in which conservative methods and techniques prove ineffective and fail to achieve the desired effect.
2. Injuries to the thoracic and lumbar spine:
   1. uncomplicated compression wedge-shaped fractures of the bodies of the lumbar and lower thoracic vertebrae;
   2. comminuted compression fractures of the lumbar vertebral bodies;
   3. fractures and dislocations of the lumbar and thoracic spine.

Contraindications: lack of necessary qualifications and sufficient experience of the surgeon, necessary equipment, facilities and well-established anesthesiology service; serious condition of the victim due to existing spinal injury or concomitant serious injuries that exclude the possibility of surgical intervention; presence of diseases that exclude the possibility of surgical intervention; biologically elderly age of the victim.

Pain relief. When choosing a method of pain relief, it is necessary to be guided by the following two main provisions - the safety of the method of pain relief for the victim and convenience for the operating surgeon. With regard to surgical interventions on the spine, endotracheal anesthesia best meets these two requirements.

Conducted by a qualified, experienced anesthesiologist, modern endotracheal anesthesia appears to be the safest for the victim. This type of anesthesia also creates maximum convenience for the surgeon. Muscle relaxation and switching off spontaneous breathing create significant convenience during interventions performed on the lumbar spine using extraperitoneal surgical approaches. Controlled breathing eliminates the dangers associated with accidental injury to the pleura during extrapleural approaches to the bodies of the thoracic vertebrae, with injury to the mediastinal or parietal pleura on the opposite side when using transpleural surgical access. Wide opening of the pleural cavity, manipulations in the area of the posterior mediastinum, near the pericardium and roots of the lungs, the aortic arch and large blood vessels branching off from it inevitably lead to disruption of external respiration and hemodynamics, in particular, central venous pressure. Thoracotomy performed under controlled breathing conditions allows to compensate to a large extent for the negative effects of pneumothorax. The role of this type of anesthesia in surgical interventions on the cervical spine is invaluable. The ability to switch to long-term controlled breathing at any time if necessary in case of injuries or surgical interventions on the cervical spine allows to confidently perform the necessary manipulations on both the anterior and posterior sections of the cervical vertebrae, the lower, middle and especially the upper sections of the cervical spine.

Resuscitation. Surgical interventions on the anterior sections of the injured spine are carried out in inevitable contact with large main blood vessels. In case of injury to these large, especially venous, vessels, massive bleeding may occur, leading to severe collapse and even clinical death. The life of the victim in these cases depends on the speed and completeness of the manipulations carried out to revive the victim. Therefore, surgical interventions on the spine must be arranged so that all necessary resuscitation measures can be started immediately. In addition to special resuscitation equipment (sets for intra-arterial blood transfusion, tracheostomy set, automatic breathing apparatus, defibrillator, etc.) and a set of necessary medications. A special doctor is assigned to assist the anesthesiologist, who is proficient in all resuscitation manipulations and is ready to immediately begin their implementation. In advance, before the operation, it is necessary to prepare the most accessible venous and arterial trunks for quick exposure, so as not to waste precious minutes searching for them when needed.

The use of posterior surgical approaches in a number of surgical interventions on the spine is not associated with the need for direct contact with large arterial and venous trunks. Despite this, blood loss during these surgical interventions is incomparably greater than when using technically correctly performed anterior surgical approaches. Therefore, during surgical interventions on the posterior spine, the amount of blood loss should be monitored most carefully and blood loss should be replenished in a timely manner.

As a rule, with anterior approaches, the spine is exposed without blood loss, and only manipulations on the vertebrae lead to it. The amount of blood loss in these cases is directly proportional to the volume of manipulations on the spine - the wider the spongiosa is exposed, the greater the number of vertebral bodies deprived of compact bone, the greater the blood loss. Blood loss especially increases during manipulations near the roots of the arches and intervertebral openings. Blood loss can be significant during surgical interventions for old spinal injuries. During surgical interventions on the bodies of children's vertebrae, significant bleeding from the basivertebral vessels can occur.

The preparation of the victim for surgery depends on the nature of the existing injury, its location, the urgency of the intervention, the condition of the victim, the presence or absence of concomitant injuries and diseases.

Surgical approach. The success of surgical intervention largely depends on rational access to the object of intervention. Existing surgical approaches to the vertebral elements can be divided mainly into anterior and posterior. Posterior surgical approaches are most widely used in surgical interventions for various spinal injuries. Without denying the importance and benefit of these approaches for certain interventions on the posterior spine, we emphasize that these approaches do not justify themselves in a number of surgical interventions on the damaged spine. At the same time, anterior - direct approaches to the vertebral bodies and intervertebral discs, most often subject to damage, are far from being used enough in spinal injury surgery. There is a misconception that anterior approaches to the spine are too difficult and risky for victims, sometimes aggravating their already serious condition. The amount of blood loss and the severity of the condition of those operated on through posterior surgical approaches are incomparably greater, the postoperative period is more difficult and difficult and fraught with lesser, but greater complications.

The main advantages of anterior surgical approaches, when appropriately indicated, are that they provide: wide access to the anterior sections of the damaged spine; the possibility of expanding this access during the intervention, if necessary; the possibility of visual control over manipulations on the spine; the possibility of one-stage intervention in case of multiple vertebral injuries; the possibility of one-stage intervention in case of certain types of combined injuries; minimal risk of damage to paravertebral anatomical structures and elimination of complications if they arise; no direct contact with the spinal cord, its membranes, spinal roots, ganglia, etc.; preservation of the posterior undamaged sections of the spine.

All of the above benefits are extremely important.

Manipulations on the damaged spine. The nature of the manipulations performed on the damaged section of the spine depends in each individual case on the clinical form of the existing injury, the presence or absence of complications from the contents of the spinal canal, the condition of the victim and the goals and objectives that need to be achieved by this intervention. Some provisions should be emphasized.

1. In unstable injuries, various types of bone grafting on both the anterior and posterior sections of the damaged spine do not create early primary stability of the damaged section of the spine. In these cases, stability occurs only after the onset of a bone block, after the time required for the implantation and reconstruction of bone grafts.
2. Early primary stability of the damaged segment of the spine can only be achieved by fixing the damaged segment of the spine with rigid metal fixators.
3. Usually, various metal or other rigid fixators are viable for a certain period of time, after which they lose their useful function. This period of viability of metal structures should be used wisely to obtain permanent stability using bone plastic fixation.
4. The most appropriate method is to perform simultaneous stabilization using metal structures and bone grafting, if there are appropriate indications. In these cases, early stabilization will be provided by metal structures, and final stabilization will be provided by the bone block that has arisen during this time.
5. If it is impossible to perform one-stage stabilization of the damaged section of the spine with metal structures and bone plastic fixation, if there are appropriate indications, spondylodesis with bone grafts should be performed in a second stage before lifting the victim to a vertical position.
6. In case of stable injuries, the use of metal fixators and various types of bone grafting proves to be effective.
7. More perfect and harmonious "implantation" of autograft inserts give preference to autobone. Homobone can be used only for forced indications.