Cervical spine hyperextension injury
Cervical hyperextension injury is also called “whip injury”, with the expansion of the highway and the increase of speed, this kind of injury is increasing in recent years, and clinicians with insufficient clinical experience are prone to miss and misdiagnose it, which should be taken seriously. Most of the more serious injuries have residual sequelae, especially the impact on hand function is greater. The main pathological and anatomical changes are located in the central canal of the spinal cord, so it is also known as “central canal syndrome”.
Injury mechanism of cervical hyperextension injury
The mechanism of injury is mostly seen when the vehicle brakes sharply or crashes at high speed. At this time, due to the role of inertial force, the face, jaw, frontal and other parts of the impact from the front, and the head and neck backward over-extension; instantly, the head and neck and forward flexion, therefore, also easy to cause flexion injury. In addition, other violence from the front, supine neck position from a high fall, as well as the neck was pulled by the violence of upward and backward direction can produce the same consequences.
In normal cervical extension, the spinal cord and the dural sac in the spinal canal are compressed and shortened in a folded fashion; however, if the anterior longitudinal ligament is ruptured and the vertebral space is separated, the spinal cord can be stretched backwards. In this case, if the cervical spinal canal of the injured person is narrow, the spinal cord will be easily embedded in the sudden convexity and invagination of the ligamentum flavum and the bony canal wall in front of the spinal canal; especially if there is a posterior nucleus pulposus or bone spur formation in front of the spinal canal, such hedging pressure will be easily concentrated in the central canal of the spinal cord, which will cause congestion, edema or bleeding around the area.
Clinical manifestations of cervical hyperextension injury
I. Neck symptoms
In addition to pain in the posterior part of the neck, the involvement of the anterior longitudinal ligament is often accompanied by pain in the anterior part of the neck, and the movement of the neck is obviously restricted, especially in supination and extension, and there is obvious pressure pain around the neck.
Symptoms of spinal cord damage
Because the pathological changes are located around the central canal, the closer the lesion is to the central canal, the more serious the lesion is, so the deeper the cone bundle is involved first. Clinically, the symptoms of upper limb paralysis are more severe than those of lower limbs, and hand dysfunction is more severe than that of shoulder and elbow. The clinical manifestation of sensory involvement is the loss of temperature and pain sensation, but the presence of position and deep sensation, which is called sensory dissociation. Severe cases may be accompanied by fecal incontinence and urinary retention.
Imaging examination
Typical cases on the X-ray film mainly show.
1, prevertebral shadow widening when the plane of injury is high, mainly manifested as the posterior pharyngeal soft tissue shadow widening, while the plane of injury in the cervical 4-5 vertebrae below, the posterior laryngeal ventricular shadow significantly widened.
The height of the anterior border of the vertebral space of the damaged vertebral segment is wider than that of other vertebral segments, and small bone fragments can be torn off at the anterior superior border of the damaged vertebral segment.
MRI examination is of great significance in determining the degree of disc herniation and spinal cord involvement, and should be considered routine in every case.
[Treatment of cervical hyperextension injury
I. Acute treatment
Non-surgical treatment is the main treatment. In addition to general treatment measures, the following points should be noted.
1, cervical braking and fixation should be used early cranial or Glisson’s band line continuous traction; traction force line slightly forward flexion, generally 5 ° -10 °, do not supine extension. Traction weight should not be too heavy, 1.0-1.5kg is enough.
2, keep the airway unobstructed especially for the injury plane is high, should be inhaled oxygen or tracheotomy as appropriate.
3, spinal cord dehydration therapy in the clinic mostly with dexamethasone and tachyphylaxis.
4, prevention of complications and limb function exercise should pay attention to the prevention of complications such as pneumonia, urinary tract stones and decubitus ulcers, and strengthen the functional exercise and rehabilitation of both upper limbs, mainly the hand.
Second, surgical treatment
It is not suitable to be performed in the early stage, unless there is a clear bony compression; generally choose 1 week after the injury, when the trauma reaction has subsided and the condition is mostly stable. The choice of surgery can be divided into two types of decompression surgery: anterior and posterior. For spinal stenosis and ligamentous lesions, posterior cervical decompression should be performed and the sagittal diameter of the spinal canal should be enlarged. In the case of bony compression in the spinal canal, the anterior or posterior resection should be decided depending on the location of the compression bone. For those with spur formation at the posterior edge of the vertebral body, the anterior approach should be chosen; while removing the compressive bone and restoring the height of the vertebral segment and the line of the spinal canal, the anterior cervical locking plate or Cage internal fixation can be used.
Prognosis of cervical hyperextension injury
In general, most of the spinal nerve function can be restored, especially in mild cases, and no sequelae can be left after recovery. However, in cases with more serious injuries around the central canal, it is difficult to fully recover the hand function. In cases with other injuries, residual bone in the spinal canal, sagittal diameter of the spinal canal less than 10 mm and delayed treatment, the prognosis is mostly unsatisfactory.