Cervical spine trauma.

Cervical spine injury, especially in adults, is one of the most severe types of injury. Such injuries are characterized by:

• high risk of developing severe neurological complications, including tetraplegia;
• high frequency of fatal injuries, with death often occurring at the pre-hospital stage;
• the varied nature of bone damage, caused by the unique anatomical structure of the cervical spine.

The severity of a cervical spine injury is often aggravated by inadequate medical care. This is due to several factors, both objective and subjective:

• doctors, including traumatologists and neurosurgeons, are practically uninformed about the characteristics of cervical spine injuries and methods of their management;
• At present, the “market” of cervical orthoses is not sufficiently filled, the role of which at the stages of treatment of cervical spine injuries is difficult to overestimate;
• There is clearly a continuing shortage of modern domestic instruments for low-trauma operations on the cervical spine, including means for its internal instrumental fixation. This does not allow for a sufficient volume of full-fledged surgical interventions on all parts of the cervical vertebrae and in the craniovertebral zone.

All of the above necessitated the need to acquaint the reader with the most common types of injuries to the atlantoaxial joint and cervical vertebrae, some typical mechanisms of their occurrence, as well as the basic principles of their management.

Anterior Q dislocation, accompanied by a rupture of the transverse ligament and a sharp narrowing of the retrodental distance (SAC, see abbreviation), is in most cases a lethal injury due to compression of the distal medulla oblongata and cranial spinal cord by the C2 tooth. This type of injury requires fixation of the cervical spine and head in the head extension position. Conservative methods, as a rule, fail to achieve adequate stability of the Q-C2 segment, which leads to the development of chronic atlantoaxial instability, which in this case is potentially lethal and requires early or delayed surgical fixation.

Anterior subluxation of C1 with a fracture of the base of the C2 tooth is a more favorable injury in terms of neurological complications compared to anterior dislocation of C1. In children, an analogue of a C2 tooth fracture is a rupture of the corporodental synchondrosis or epiphysiolysis of the C1 tooth. Treatment of this injury consists of traction on the Glisson loop or in the Halo apparatus in the head extension position. After the subluxation has been eliminated, confirmed by radiographic examination, plaster or orthotic fixation is performed for 12-16 weeks in adults or 6-8 weeks in children in a rigid craniocervical bandage such as Minerva or Halo-cast hardware fixation. In the absence of fracture healing in the long term, confirmed by functional radiographs in the flexion/extension position, surgical stabilization of the craniovertebral zone is recommended.

Posterior transdental dislocation of C1 is typical for trauma accompanied by a sharp extension of the head, often noted with a blow to the submandibular zone (in adults). In newborns, this injury occurs with excessive extension of the head during childbirth, especially when using various obstetric techniques for childbirth. Reduction (reduction) of the dislocation is achieved by moderate axial traction on the head with subsequent extension-flexion movement of the head. The transverse ligament is not damaged in this type of injury, so immobilization in a corset such as Minerva or Halo-cast for 6-8 weeks is usually sufficient. Surgical stabilization is undertaken in the presence of pathological mobility of the segment in the long term or in the presence of persistent pain syndrome.

Rotational subluxation of Q is the most common type of damage to the atlantoaxial joint, the typical clinical manifestation of which is limited mobility of the cervical spine, accompanied by pain syndrome. The mechanism of its occurrence is different, most often associated with a sharp turn of the head. With concomitant Kimerly anomaly (see terms), the injury may be accompanied by acute cerebrovascular accident. Treatment consists of eliminating the subluxation with functional traction on the Glisson loop, followed by immobilization in the Shantz collar for 7-10 days.

It is necessary to pay attention that any deviation of the head from the frontal plane is accompanied on the anteroposterior radiographs of the atlantoaxial zone by projection asymmetry of the paradental spaces, lateral atlantoaxial joints, lateral masses of the atlas. This allows us to consider that for radiological confirmation of the diagnosis of rotational subluxation of the C1 vertebra, computed tomography is more objective than traditional radiological examination of this zone through an open mouth, which is accompanied by hyperdiagnosis of the specified pathology.

The peculiarity of the anatomical structure of the C2 vertebra requires attention to such a specific injury as a fracture of its odontoid process. There are three typical variants of such damage: transverse or oblique avulsion fracture of the odontoid apex at the level of the alar ligament (type I fracture), transverse fracture of the odontoid base (type II fracture), and a fracture passing through one or both upper articular processes (type III fracture). These types of damage are characterized by varying degrees of instability of the atlantoaxial segment. An avulsion fracture of the odontoid apex of C2 is rarely accompanied by fragment displacement and instability of the d-C2 segment, while for other types of fracture, mechanical atlantoaxial instability and neurological complications are typical.

Earlier we mentioned the peculiarities of the formation of corporo-dental synostosis, which can be mistaken for a traumatic injury. We will add that in children, an anatomical variant of development, designated as the odontoid bone (see terms), as well as the apophyseal growth zone of its ossification nucleus, can be mistaken for a fracture of the C2 vertebra.

Subluxations and dislocations of the cervical vertebrae can be observed both as independent injuries and in combination with fractures of the cervical vertebrae complicated by rupture of the ligamentous apparatus of the vertebral-motor segments. Depending on the degree of displacement in the intervertebral joints of the cervical vertebrae, simple and superior subluxation are distinguished, as well as linked dislocation of the vertebrae.

Radiological signs of dislocation (subluxation) of the cervical vertebrae, revealed on an X-ray in the anteroposterior projection, are:

• step-like deviation of the line of spinous processes, while:
• with unilateral anterior displacement in the facet joints, the spinous process deviates toward the affected side;
• with unilateral posterior displacement, the spinous process deviates toward the healthy side (it should be remembered that the absence of deformation of the spinous processes does not exclude the possibility of a violation of the relationship in the joints, which, according to V.P. Selivanov and M.N. Nikitin (1971), can be explained by the variability of the development of the spinous processes;
• different sizes of the transverse processes of the dislocated vertebra on the right and left: the transverse process protrudes more on the side rotated backwards, and less on the side rotated forwards;
• an increase of more than 1.5 times in the distance between the apices of the spinous processes at the level of the damaged segment;

Signs of dislocations and subluxations of the cervical vertebrae, revealed in the lateral projection, are the size of the angle formed by the lines drawn along the lower edges of adjacent vertebrae, more than 1G and local narrowing of the spinal canal.

According to the nature of the vertebral dislocation, there are "overturning" displacements of the cervical vertebrae at an angle and "sliding" displacements in the horizontal plane. Sliding dislocations are often accompanied by spinal disorders, which is associated with the narrowing of the spinal canal that occurs with this injury.

Some types of cervical spine injuries, namely fractures of the cervical vertebrae, have received special names under which they are designated in vertebrological literature.

Jefferson fracture is a fracture of the arches and/or lateral masses of the atlas C1. The typical mechanism of injury is an axial vertical load on the head. Characteristic are the presence of extensive pre- and paravertebral hematomas, neck pain. The following injury types are distinguished:

• typical Jefferson fracture - a multi-fragmentary burst ("burst") fracture or "true" Jefferson fracture, with damage to the anterior and posterior half-arches of the atlas. The presence of paired fractures (two in front and two in the back) is typical. The anterior and posterior longitudinal ligaments usually remain intact, the spinal cord is not damaged. The injury can occur without rupture of the transverse ligaments (stable injury) and with rupture of the transverse ligaments (potentially unstable injury);
• atypical Jefferson fracture - a fracture of the lateral masses of the atlas, usually bilateral, but can be unilateral. The fracture is stable.

Hangman's fracture-dislocation (hangman's fracture) is a traumatic spondylolisthesis of C2. The typical mechanism of injury is
a sharp extension of the head with an axial load. The historically established term "hangman's fracture" is associated with the fact that this injury to the cervical vertebrae is typical for those executed by hanging.

Cervical spine injury can also be observed in car accidents (direct head impact on the windshield). Depending on the degree of listhesis, 3 types of injury are distinguished:

• I - anterior displacement less than 3 mm, without rupture of the anterior and posterior longitudinal ligaments; the injury is stable;
• II - anterior displacement of more than 3 mm without rupture of the anterior and posterior longitudinal ligaments, the injury is conditionally stable;
• III - damage with rupture of the anterior and posterior longitudinal ligaments and intervertebral disc: accompanied by true instability of the spinal motor segment and complicated by spinal cord injury, up to and including its rupture.

A digger's fracture is an avulsion fracture of the spinous processes of C7, C6, T (vertebrae are classified by the frequency of injury in this injury). The typical mechanism of injury is a sharp bending of the head and upper cervical vertebrae with tense neck muscles. The name is associated with the injury sustained by a person in a pit ("digger"), on whose head, tilted forward, a load falls (collapsed earth). The injury is clinically accompanied by localized pain associated only with the injury to the posterior column of the spine. The injury is mechanically and neurologically stable.

Diving injury is a blast fracture of the cervical vertebrae below C2, accompanied by rupture of the anterior and posterior longitudinal ligaments, posterior interosseous ligaments and intervertebral disc. The typical mechanism of injury is axial loading, with sudden flexion of the head and neck. The injury is mechanically and neurologically unstable.

Injuries to the cervical spine of the C3-C7 vertebrae, accompanied by stretching of the anterior and posterior support complexes, are classified as type “C” (the most severe) in the AO/ASIF classification due to the worst prognosis and the need for more active surgical treatment.

Instability of the cervical spine. The term instability has become especially widely used in recent years in relation to the cervical spine, which is associated with increasing attention to its pathology. The diagnosis is most often made on the basis of X-ray data, while not only the age-related characteristics of the cervical spine are not taken into account (the physiological mobility of the cervical spinal motor segments in children is significantly higher than in adults), but also the constitutional features characteristic of some systemic dysplasias, primarily such as hypermobility of the spinal motor segments.

NoAO/ASIF Classification of Cervical Vertebrae Injuries

Damage level	Fracture type
	A	IN	WITH
Atlas fracture (C1)	Fracture of only one arch	Burst fracture (Jefferson fracture)	Dislocation of the atlantoaxial joint
C2 fracture	Transisthmal fracture (vertebral arch fracture or hangman's fracture)	Fracture of the odontoid process	Transistal fracture combined with tooth fracture
Fractures (damage)	Compression fractures	Injury to the anterior and posterior support complexes with or without rotation	Any damage to the anterior and posterior support complexes with stretching

To assess the severity of clinical manifestations of cervical myelopathy of various etiologies (caused by congenital defects of the cervical spinal canal, traumatic injuries, spondylosis and other degenerative diseases), the Japanese Orthopedic Association (JOA, 1994) proposed a 17-point assessment scale. The scale looks somewhat exotic (due to some national characteristics), but this does not reduce its significance and, with appropriate modification, it can be used in any other country. We used the principles laid down in the JOA scale when creating our own scale for assessing the adaptation status of patients with spinal pathology.

If it is impossible to precisely determine the parameter being assessed (an "intermediate value"), it is assigned the lowest score. If there is an asymmetry in the scores being assessed on the right and left sides, the feature is also assigned the lowest value.

JOA scale for assessing the severity of clinical manifestations of cervical myelopathy

Evaluated indicators	Evaluation criteria	Points
Motor functions of the upper limbs	Patient...
	Cannot independently eat food using cutlery (spoon, fork, chopsticks) and/or cannot button buttons of any size;	0
	Able to feed independently using a spoon and fork, but cannot use chopsticks;	1
	Can, but hardly ever uses chopsticks, can write with a pen or can button his cuffs;	2
	Can and does use chopsticks to eat, writes with a pen, and buttons his cuffs;	3
	Has no limitations on the functions of the upper limbs.	4
Motor functions of the lower limbs	Patient...
	Can neither stand nor walk;	0
	Cannot stand or walk without a cane or other external support on the ground;	1
	Can walk independently on a horizontal surface, but needs help to climb stairs;	2
	May walk quickly, but awkwardly.	3
	Has no limitations on the functions of the upper limbs.	4
Sensitivity
A. Upper limbs	Obvious sensory disturbances	0
	Minimal sensory disturbances	1
	Norm	2
B. Lower limbs	Obvious sensory disturbances	0
	Minimal sensory disturbances	1
	Norm	2
S. Body	Obvious sensory disturbances	0
	Minimal sensory disturbances	1
	Norm	2
Urination	Urinary retention and/or incontinence	0
	Feeling of delay and/or increased frequency and/or incomplete emptying and/or thinning of the stream	1
	Violation of urinary frequency	2
	Norm	3
Maximum amount of points		17

The level of radiodiagnostics of various pathological conditions of the cervical spine, which has increased in recent years, has led to a situation where the detected changes are a priori accepted as the cause of complaints, most often of a general cerebral nature. Neither the clinical features of the symptoms nor the absence of pathological signs revealed by other objective research methods are taken into account - i.e., everything that allows one to question the vertebrogenic nature of the complaints presented. The diagnosis of "cervical spine injury" should be established only based on a combination of clinical symptoms, data from radiological diagnostic methods (primarily X-ray and/or MRI) and a functional study of the blood flow of the main vessels of the head in the neck area.

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