Injuries of the Spinal Cord and Vertebrae
Most spinal cord injuries result from motor vehicle crashes, falls, assaults, and sports injuries.
Symptoms, such as loss of sensation, loss of muscle strength, and loss of bowel, bladder, and sexual function may be temporary or permanent.
Magnetic resonance imaging or computed tomography is the best way to identify the injury.
Treatment involves immobilization of the spine, drugs to relieve symptoms, sometimes surgery, and usually rehabilitation.
Injuries may affect the spinal cord or the roots of the spinal nerves, which pass through the spaces between the back bones (vertebrae) of the spine. The bundle of nerves that extend downward from the spinal cord (cauda equina) may also be injured. Injuries of the spinal cord cause nerve damage or dysfunction in one the following ways:
Because the spinal cord is surrounded and protected by the spine, injuries of the spine or its connective tissue (such as disks and ligaments—see see Figure: A Herniated Disk) can also injure the spinal cord. Such injuries include the following:
Attachments may be loosened so much that the vertebrae move freely. These injuries are considered unstable. When vertebrae move, they can compress the spinal cord or its blood supply and damage spinal nerve roots. An unstable injury to the spine may not damage the spinal cord immediately. For example, the injury may cause muscle spasms that prevent the vertebrae from moving much. However, after hours or days, muscle spasms may subside, allowing the vertebrae to move freely and damage the spinal cord.
Almost all people with a spinal cord injury have an injury to the spine. However, sometimes children do not.
The most common cause of spinal cord injuries is motor vehicle crashes, accounting for almost half of them. Other causes include falls, sports, work-related accidents, and violence (such as a knife or gunshot wound). Among older people, falls are the most common cause.
If the spine is injured, people usually feel pain in the affected part of the neck or back. The area over the injury may be tender to the touch, particularly if a fracture is present. If the spinal cord is injured, the nerves at and below the site of the injury malfunction, causing loss of muscle control and loss of sensation. However, children may have spinal cord injuries in which nerves malfunction only temporarily and briefly. They may have lightning-like pains that shoot down the arms or legs.
When nerve damage occurs, loss of muscle control or sensation may be temporary or permanent, partial or total, depending on the severity of the injury. An injury that severs the spinal cord or destroys nerve pathways in the spinal cord causes permanent loss, but a blunt injury that jars the spinal cord may cause temporary loss, which can last days, weeks, or months. Sometimes swelling causes symptoms that suggest an injury more severe than it is, but the symptoms usually lessen as the swelling subsides.
Partial loss of muscle control results in muscle weakness. Paralysis usually refers to complete loss. When muscles are paralyzed, they often go limp (flaccid), losing their tone. Muscle reflexes that doctors check using a reflex hammer are weak or absent. But when the spinal cord is injured, paralysis may progress weeks later to involuntary, prolonged muscle spasms (called spastic paralysis). In this case, muscle reflexes are stronger than normal.
For people who are weak or paralyzed, movement is limited or impossible. Consequently, they are at risk of developing blood clots, pressure sores, permanently shortened muscles (contractures), urinary tract infections, and pneumonia.
People who have symptoms of spine injury (such as significant pain in the bones of the neck or back) and children who have even brief symptoms of possible nerve damage or pains that shoot down the arms or legs need to be evaluated in an emergency department.
Injuries to the spine (affecting bones) and spinal cord are diagnosed by imaging tests.
X-rays: After an injury, an x-ray is often done. X-rays can be done immediately, usually while the person is still in an emergency department. X-rays show major injuries of the spine but do not show injuries of the spinal cord. X-rays are usually abnormal if the person has a spinal cord injury but may not show every detail of the injury.
Computed tomography (CT): Whether or not x-rays are done, CT is done after a spinal injury. CT is the most accurate test for injuries of the spine and can show most injuries of the spinal cord.
Magnetic resonance imaging (MRI): MRI is the best test for injuries of the spinal cord and the ligaments of the spine. However, CT is generally done before MRI is done because MRI is less readily available than CT and does not show spine injuries in as much detail as CT.
People who may have a spinal cord injury should not be moved except by emergency personnel. The first goals are to make sure people can breathe and to prevent further damage. Thus, emergency personnel take great care to keep the neck immobile when moving a person with a possible spinal cord injury. Usually, the person is strapped to a firm board and carefully padded to prevent movement. A rigid collar may be used to keep the neck from moving. When the spine is severely damaged, the vertebrae may no longer be held in place or may be broken, making the spine unstable. Thus, even slight movement of the injured person can cause the spine to shift, putting pressure on the spinal cord. Pressure on the cord increases the risk of permanent paralysis.
Surgery is needed to remove blood and bone fragments if they have accumulated and are pressing on the spinal cord. If the spine is unstable, people are immobilized until the bone and other tissues have had time to heal. Sometimes a surgeon implants steel rods to stabilize the spine so that it cannot move and cause additional injury. If an injury causes only partial loss of function, surgery done soon after the injury may enable people to recover more function and become mobile sooner. However, the best time for surgery is debated. Spinal surgery may be done by neurosurgeons or orthopedic surgeons.
Drugs may be useful.
Corticosteroids: If the injury is caused by a blunt force, doctors may immediately give corticosteroids, such as methylprednisolone, by injection to help prevent swelling around the injury. The drugs must be started within 8 hours of the injury to be effective and should be continued for about 24 hours. However, not all doctors think corticosteroids are helpful because it is unclear whether the benefit outweighs the risk of side effects.
Pain relievers (analgesics): If the injury causes pain, analgesics are given. During the first hours and days, opioids are usually used. Milder analgesics, such as acetaminophen or ibuprofen, may be used later.
Muscle relaxants: If spastic paralysis develops, muscle relaxants, such as baclofen or tizanidine, may be used.
Good nursing care can help prevent complications due to bed rest, such as pressure sores, urinary tract infections, blood clots in the legs, and pneumonia (see Problems Due to Bed Rest).
Experimental treatments to stimulate growth of spinal nerves are being studied. For example, a certain type of white blood cell (macrophage) can be extracted from the blood, then injected back into the injured person. The injected macrophages help speed the removal of waste products generated by the body’s reaction to the injury and secrete substances that may help the nerves regenerate. Experimental drugs can be injected into the space around the spinal cord (epidurally) or taken by mouth. Using stem cells (unspecialized cells from which other more specialized cells can be derived) is another possibility, but this treatment requires much more study.
Rehabilitation, including physical and occupational therapy, can help people recover more quickly or more completely (see Rehabilitation After a Spinal Injury). People usually need emotional support, and often counseling and antidepressants, because depression usually develops when injury results in disability.