Navigation

Dislocation and subluxation of the vertebrae

Автор: ,

Dislocation and subluxation of the vertebrae

Dislocation of the vertebrae is a rare phenomenon. Vertebral fractures complicated by dislocations are much more common. In its pure form, dislocations occur almost exclusively in the area of the cervical vertebrae. The upper vertebra is considered dislocated. There are flexonal and rotational types of dislocations. Excessive extension meets an obstacle when the vertebral arches approach, which prevents dislocation. Excessive bending of the head to the chest can displace the articular processes of the upper vertebra relative to the lower one (incomplete dislocation, subluxation). With the subsequent straightening of the spine, the articular surfaces of the upper vertebra can slide further, being installed in front of the articular processes of the lower vertebra, "jumping" behind them (complete dislocation). In this case, the head acts as a lever force with a fulcrum on both anterior edges of the articular surfaces of the underlying vertebra. Therefore, flexion (flexion) dislocation of the cervical vertebrae is always bilateral.

Excessive extension or flexion from a neck injury can dislocate the cervical vertebrae and form a dislocation.

In rotational dislocation with excessive lateral flexion and ligament stretching, the articular process of the upper vertebra rests on the arch of the lower one (as in the fulcrum). With further movement, the articular processes of one side diverge, as in flexion dislocation, incomplete or complete dislocation. On the opposite side, during rotation (rotation), the upper articular process (due to stretching of the articular capsule) moves posteriorly from the lower vertebra. Thus, with rotational dislocation, the vertebrae are displaced on both sides, but in opposite directions. Because the adhesion of the articular processes here occurs on one side, rotational dislocation is otherwise called unilateral.

Both flexion and rotational dislocation are observed only in the cervical spine - with a sharp bend of the neck (in horizontally located articular processes):

  • flexion dislocation - with complete rupture of the capsules of both intervertebral joints
  • rotational dislocation - with rupture of the capsule of the intervertebral joint on the side of rotation

When X-ray of the cervical spine in the lateral projection, it is not possible to see the displacement of the vertebral body after injury, because the patient's shoulders obstruct the view.

 

Diagnostics of the dislocation and subluxation of the vertebrae

Symptoms of flexion dislocation of the cervical spine:

  • the patient's head is tilted forward
  • the patient's chin almost touches the sternum

Due to significant mobility and sharp pains in the back of the head, neck, and shoulders, patients often hold their heads with their hands while walking. When examining the spinous processes of the cervical spine, one can see the protrusion of the spinous process of the underlying vertebra. Up from it, the impression of the overlying vertebra is felt. The standing anteriorly of the body of the overlying vertebra makes it difficult to swallow. A dislocated cervical vertebra is felt through the pharynx or determined by laryngoscopy.

Computed tomography (CT) of the cervical spine shows anterior displacement of the C5 vertebral body after injury (indicated by an arrow).

CT scan of the cervical spine reveals a fracture with dislocation of the C7 vertebra, the coupling of the facet joints.

With rotational unilateral dislocation of the cervical vertebra, the position of the patient's neck and head may be different, depending on the degree of dislocation. In case of incomplete dislocation, the neck is extended, and the head is tilted and turned to the healthy side. In case of complete dislocation, the patient's head is tilted towards the chest, and the dislocation and turned (rotated) into a healthy one. The spinous processes of the upper vertebrae will be deflected towards the dislocation. With both types of dislocations of the cervical vertebrae, concomitant neurological symptoms occur:

  • changes in the sensitivity of the radicular nature (hypesthesia, paresthesia, analgesia)
  • paresis and paralysis of the muscles of the upper extremities - as a result of compression or damage to the roots (mono- or paraparesis, paraplegia)

Paralysis of the muscles of the four limbs (quadriplegia) will indicate damage to the substance of the spinal cord. The severity of these neurological symptoms is critical for prognosis. A fatal outcome is not uncommon.

On MRI of the cervical spine, the lateral image shows displacement of the C7 vertebral body and a fracture of the Th1 body, forming compression of the spinal cord at this level after injury (indicated by arrows).

 

Treatment of dislocation and subluxation of the vertebrae

Reduction of dislocation and subluxation of the vertebrae is not an easy task, even under anesthesia. Incomplete unilateral dislocations of the cervical vertebrae are adjusted more easily - by stretching the neck behind the head (along the length of the body) with a Glisson loop and turning it in the opposite direction; complete dislocations of the cervical vertebrae, that is, those where there is a "grip", need to be released from it by bending the head towards the dislocation, followed by its rotation into a healthy one, with constant extension. Having freed from the clutch and continuing the traction, the reverse maneuver is performed: abducting the head to the healthy side, followed by rotation towards the dislocation.

The Gardner-Wells brace is used in emergency care; the length of the neck is stretched through an adjustable block attached to an X-ray transparent table.

It is recommended to turn the flexion dislocation of the cervical vertebra into rotational, unilateral, and then reposition it. After reduction, a stabilizing operation is performed to fix the vertebrae (discectomy with anterior and posterior fusion). For this purpose, various designs of fixing plates, implants (cages), and transpedicular fixing screws are used.

Most often, in the cervical spine, such dislocations occur at the level of the C3-C5, C5-C6 vertebrae, that is, in the middle part of the cervical spine, where the general anterior mobility is greatest. In the area of the two upper cervical vertebrae (C1 and C2), where there are no cartilaginous discs, and the joints are wide, they are strengthened with such a powerful ligamentous apparatus that dislocates at this level are a rare and exceptional phenomenon. Dislocation of the C1 vertebra (dislocation of the skull relative to the atlas), is possible either with a sharp bend of the head or with its rotation (rotation), which is almost always fatal.

The same can be said about dislocations of the C1 vertebra (atlas) relative to the underlying C2 vertebra (epistopheus) if it is not accompanied by a fracture of its odontoid process. The cervical C2 vertebra is firmly connected to the anterior arch of the atlas (C1 vertebra):

  • transverse ligaments
  • pterygoid ligaments
  • cruciate ligaments with the anterior edge of the foraminis occipitalis magni in the occipital bone of the skull

Wearing a neck brace (Philadelphia collar) when treating sprained ligaments and injured neck joints.

When the head is tilted sharply with traction (for example, when hanging), these ligaments can rupture. When the C1 vertebra (atlas) is displaced forward, the odontoid process of the C2 vertebra crushes the spinal cord in the spinal canal, and instant death occurs. The fractured odontoid process of the C2 vertebra is displaced from the anterior arch of the C1 vertebra (atlas) forward, and in this case, the spinal cord is not compressed. With increased flexion of the neck (hyperflexia), fractures of the bodies or articulated vertebrae are often possible here.

Conservative treatment for dislocation of the articular processes of the subaxial (C3-C7 vertebrae) of the cervical vertebrae consists of temporary immobilization of the neck for a period of 6 to 12 weeks. During this period, the damaged ligaments, tendons, and muscles of the neck, being at rest, have time to recover. Compliance with these deadlines is especially important for ligaments because the metabolic process in them is much slower than in muscles, in which the vascular network is well developed. To immobilize the cervical spine, a cervical corset (Philadelphia collar) or an external restraint system (Halo System) is used.

Wearing a neck brace (Philadelphia collar) in the treatment of dislocation or subluxation of the articular processes of the cervical vertebrae.

Surgical treatment of dislocation of the articular processes of the cervical vertebrae is performed in two stages:

  • immediate closed reduction of dislocation, subsequent MRI, then surgical stabilization of the cervical vertebrae
  • immediate MRI, then - open reduction of the dislocation with surgical stabilization of the cervical vertebrae

The sequence of these steps depends only on the clinical status of the patient and the type of damage present.

The first treatment option is applicable for unilateral or bilateral dislocation of the articular processes of the cervical vertebrae with neurological symptoms in patients who are conscious and with adequate behavior. Closed reduction is not performed in patients with impaired consciousness and inappropriate behavior. Surgical stabilization follows the successful closed reduction of the dislocation. Unilateral dislocation is technically more difficult to eliminate, but much more stable after reduction. Bilateral dislocation is technically easier to correct (due to rupture of the posterior longitudinal ligament), but less stable after reduction.

After the stage of reduction, an MRI examination is performed and subsequent surgical stabilization of the cervical vertebrae. Posterior transpedicular fixation and sometimes anterior discectomy with fixation can be performed in the absence of significant hernial protrusions of the intervertebral discs. Anterior discectomy with fixation is always indicated for severe violations of the integrity of the intervertebral disc. About a third of all cases of closed reduction of dislocation of the articular processes of the cervical vertebrae may be ineffective and require the use of the open reduction technique.

The operation of the posterior fixation of the cervical vertebrae and the occipital bone in case of damage to the neck at the level of the axial vertebrae (C1-C2) and the cervico-occipital joint.

The second treatment option is applicable for unilateral or bilateral dislocation of the articular processes of the cervical vertebrae with symptoms in patients with impaired consciousness and inappropriate behavior. Also, this option is used in patients with dislocation, which could not be corrected in a closed way. An MRI scan is performed, followed by open reduction and stabilization of the cervical vertebrae. If the hernial protrusion is localized anteriorly, then discectomy with an anterior approach is performed.

Techniques for eliminating dislocation of the articular processes of the cervical vertebrae:

Technics
Description of dislocation reduction
Closed reduction With axial traction of the cervical spine, adding weight, gradually increase the effort. An additional movement to bend the neck (tilting the head forward) can help to reduce the dislocation. As the weight (traction force) is added, a neurological examination and X-ray of the cervical spine are performed. If the patient's neurological symptoms worsen, traction (traction) of the neck is stopped and an MRI scan is performed. To carry out a closed reduction of dislocation of the vertebrae, it is required:
  • adequate anesthesia
  • sedation of the patient
  • respiratory function control
  • a series of radiographs of the cervical spine in frontal and lateral projections
Anterior open reduction and fixation with discectomy This treatment method is indicated for:
  • reduced dislocation of the articular processes, which was carried out in a closed way, with a hernial protrusion of the disc anteriorly
  • unilateral dislocation of the articular process, which could not be eliminated by a closed method, with a hernial protrusion of the disc anteriorly
Features of open anterior reduction:
  • can be used to eliminate unilateral dislocation of the articular process
  • the reduction technique includes distraction of the vertebral bodies with a Caspar expander, followed by a rotation of its proximal part towards the dislocation
  • not effective for eliminating bilateral dislocation of the articular processes.
Posterior reduction and transpedicular stabilization This method of treatment is applicable for:
  • the impossibility of eliminating the dislocation of the articular processes by closed or anterior open methods
  • absence of anterior hernial disc protrusion
Features of open posterior reduction and transpedicular fixation:
  • performed using screws in the lateral parts (pedicals and body) of the vertebrae
  • fixation of two levels is usually required due to the lack of adequate stability of the lateral masses at the level of dislocation
Combined anterior decompression and posterior reduction / stabilization This method of surgery is indicated in the presence of a hernial protrusion of the disc in the anterior direction, requiring decompression in patients with dislocation, which was not eliminated by closed or open anterior reduction. Features of the technique of the operation:
  • first, an anterior discectomy is performed, then an anterior plate is installed at the same level, which is fixed only to the body of the superior vertebra
  • incomplete fixation with the plate prevents re-dislocation and allows the rotation of the vertebrae during posterior reduction
  • this technique eliminates the need for a repeat anterior procedure

In the thoracic region, the spine, being connected to the ribs, is inactive and can move only after fractures of adjacent (articulated) vertebrae.

Operation of anterior fixation of the cervical vertebrae in case of damage to the neck at the level of the subaxial vertebrae (C4-C5-C6).

The same can be said about the more mobile lumbar spine, reinforced with powerful long and short ligaments. The range of motion during flexion at the lumbar level of the spine is more pronounced than its rotation and tilt. In the lumbar vertebrae, the platforms of the articular processes are located in the frontal plane. This anatomical feature also prevents dislocation of the lumbar vertebrae during flexion.

Chronic sliding of the L5 body forward and downward from the sacrum was first described by Killian under the guise of spondylolysis and spondylolisthesis, and Lambl under the name of "spinal dislocation". Spondylolisthesis is an inevitable consequence of a congenital defect in the development of the arches of the vertebrae (the area between the articular processes), most often found in the arch of the L5 vertebra. The clinical picture of spondylolysis and spondylolisthesis described by Turner occurs in both women and men. Clinical manifestations of this defect in the form of spondylolisthesis are observed under the influence of sudden physical exertion, increased severity, etc. In women, repeated pregnancy can cause the gradual development of the same symptom (spondylolisthesis). in the process of fetal growth, the ligaments soften. The softening of the ligaments provides the necessary mobility of the joints of the pelvic bones for the smooth passage of the fetus during childbirth.