If you suffer an injury that severs or compresses the spinal cord in your neck or back, there is a good chance that you will be paralyzed from the point of injury downward for the rest of your life. This is called a “spinal cord injury,” or SCI for short. A little neurology and anatomy will be of immense help here.
The central nervous system (CNS) is made up of two parts: the brain and the spinal cord. The spinal cord runs from the base of the brain down the back to the tailbone. The spinal cord is protected by the spinal column, which consists of bones with a hole in the middle of them. These bones are called the vertebrae. At the top of the spinal cord are seven vertebrae known as the cervical vertebrae (C-1 to C-7, in descending order). Running down the back are the 12 “thoracic” vertebrae (T-1 to T-12), which are in turn followed by the five “lumbar” vertebrae (L-1 to L-5). The “sacrum” (S-1 to S-5) and the “coccyx” (tailbone) make up the remainder of the spinal column. Injuries to the cervical spine resulting in paralysis of the body below a certain point are known as quadriplegia (also called tetraplegia), while injuries to the spinal column at or below the thoracic level are classified as paraplegia.
The cervical spinal nerves control signals to the back of the head, the neck and shoulders, the arms and hands, and the diaphragm. The thoracic spinal nerves control signals to the chest muscles, some muscles of the back, and parts of the abdomen. The lumbar spinal nerves control signals to the lower part of the abdomen and the back, the buttocks, some parts of the external sex organs, and parts of the leg. Sacral spinal nerves control signals to the thighs and lower parts of the legs, the feet, most of the external sex organs, and the area around the anus. As you can see, the higher the SCI to the spine, the more disabling—and potentially fatal—the injury. For instance, a spinal cord injury at the neck level may cause paralysis in both arms and legs and make it impossible for the victim to breathe without a respirator, while a lower injury may affect only the legs and lower parts of the body.
SCIs involving the cervical vertebrae usually cause loss of function in the arms and legs, known as quadriplegia (or tetraplegia). If the SCI is at or above the C-3 level (C-1 to C-3), then the ability to breathe on one’s own is affected, and it will probably be necessary to have a mechanical ventilator for the person to breathe, as was the case for actor Christopher Reeve after his tragic accident until his death. Many people with SCI at or above C-3 die before receiving medical treatment because of their inability to breathe. C-4 is a critical level, as it is the level where nerves to the diaphragm—the main muscle that allows us to breathe—exit the spinal cord and go to the breathing center.
Besides allowing for regulation of the breathing process, injuries at C-4 may also allow the person some use of his biceps and shoulders, but this will be fairly weak. Injuries at the C-5 level often result in shoulder and biceps control, but no control of the wrist or hands. If the SCI is at the C-6 level, the victim usually has wrist control, but no hand function. Victims with SCI at the C-7 level can usually straighten their arms, but may still have dexterity problems with the hands and fingers. Injury at or below the C-7 level is generally considered to be the level for functional independence.
If the SCI is at the T-1 to T-8 levels, the victim usually has control of his hands, but poor trunk control resulting from a lack of abdominal muscle control. Lower thoracic vertebra injuries (L-9 to L-12) allow good trunk control and good abdominal muscle control, and the victim’s sitting balance is very good. SCI to the lumbar and sacral regions result in decreasing control of the legs and hips, urinary system, and anus.
It is often impossible for the doctor to make a precise prognosis right away, and emergency doctors are advised not to make prognoses on the question of paralysis. There is no cure for an SCI, but the sooner the intervention, the better the chances of minimizing the damage. For example, a corticosteroid drug (methylprednisolone) administered within eight hours of the time of injury may reduce swelling, which is a common cause of secondary damage. An experimental drug currently being studied appears to reduce loss of function.
On about the third day of hospitalization following the injury-producing incident, the doctors give the victim a complete neurological examination to determine the severity of the injury and predict the likely extent of recovery. X-rays, CT scans, MRIs, and more advanced imaging techniques are also used to visualize the entire length of the spine.
Recovery, if it occurs, typically starts between a week and six months after the injury is sustained, especially as the swelling goes down. The majority of recovery occurs within the first six months after injury. Impairment remaining after 12 to 24 months is usually permanent, although with incomplete SCIs, the person may recover some functioning as late as 18 months after the injury. However, some people experience small improvements for up to two years or longer. For instance, Christopher Reeve regained the ability to move his fingers and wrists and feel sensations more than five years after he sustained a SCI to his cervical spine in a horse-riding accident. But the fact remains that only a very small fraction of persons who sustain an SCI will recover significant functioning.
Besides a loss of motor functioning and feeling below the level of injury, depending upon the level of the SCI, persons with SCI may experience other difficulties, such as:
The damage to the nerve may be complete or incomplete. With complete damage, there is a total loss of sensory and motor function below the level of the SCI; there is no movement and no feeling below the level of injury, and both sides of the body are equally affected. With incomplete damage, there is some functioning and/or sensation below the site of the SCI. For instance, a person with incomplete damage may be able to move one leg more than the other, may be able to feel parts of the body that cannot be moved, or may have more functioning on one side of the body than the other. The extent of an incomplete spinal cord injury is generally determined after spinal shock has subsided, approximately six to eight weeks after the injury is sustained. With advances in acute treatment of SCI, incomplete injuries are becoming more common than complete SCI injuries.
Accidents involving automobiles, motorcycles, and other motor vehicles, especially with Sport Utility Vehicles (SUVs) and 15-passenger vans rolling over, are the most common causes of SCIs. Spinal cord injuries due to violent acts—such as being shot or stabbed—are the second-most common type of SCI, and they are the leading type of SCI in some urban settings in the United States. SCIs due to falls are the thirdmost common type, occurring most frequently in persons aged 65 years or older. Recreational sports injuries (discussed in Chapter 15) are the fourth-most common cause of SCIs, with diving in shallow water being the sport that causes the most SCIs of all recreational sports, followed by impact in high-risk sports such as football, rugby, wrestling, gymnastics, surfing, ice hockey, and downhill skiing.
There is the risk of an earlier death for a person who suffers a SCI. The most common cause of death of SCI victims is diseases of the respiratory system, especially pneumonia. The second leading cause of death is non-ischemic heart disease; this almost always involves unexplained heart attacks, often occurring among young persons who have no previous history of underlying heart disease. Suicide is the cause of death in a substantial number of persons who sustain a SCI. Other leading causes of death involving an SCI are pulmonary emboli and septicemia (infection of the blood stream). Death rates are significantly higher during the first year after injury than during subsequent years, particularly for severely injured persons.
The financial and emotional costs associated with paraplegia and quadriplegia are enormous. The average length of the initial hospitalization following injury in acute care units is 15 days. The average stay in a rehabilitation unit is 44 days. The victim of a serious SCI will often have to go through extensive and exhaustive rehabilitation and physical therapy. Persons suffering from a serious SCI are generally treated at a regional SCI spine center. The initial hospitalization costs following an SCI are in the range of several hundred thousand dollars for paraplegics and over half a million dollars for quadriplegics. The average lifetime medical costs for victims becoming paraplegics at the age of 25 can easily top $1 million. The average lifetime costs for victims who become quadriplegics at age 25 easily reaches into the area of several million dollars.