Spinal Cord Injury Information: Levels, Causes, Recovery

Answers to Common Questions About Spinal Cord Injuries

Shepherd Center knows that you and your loved ones have many questions about spinal cord injury. Here are answers to help you learn more:

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Every year, about 17,500 people in the United States sustain a spinal cord injury. That's 48 new injuries every day. Most of these people are injured in auto accidents, falls, violence and sports-related accidents. The average age of newly injured patients is 42, and 81 percent of them are men.

A spinal cord injury (SCI) is damage to the spinal cord that results in a loss of function, such as mobility and/or feeling. Frequent causes of spinal cord injuriesare trauma (car accident, gunshot, falls, etc.) or disease (polio, spina bifida, Friedreichs ataxia, etc.).

The spinal cord does not have to be severed for a loss of function to occur. In fact, in most people with spinal cord injury, the cord is intact, but the damage to it results in loss of function. Spinal cord injury is very different from back injuries, such as ruptured disks, spinal stenosis or pinched nerves.

A person can "break their back or neck" yet not sustain a spinal cord injury, if only the bones around the spinal cord (the vertebrae) are damaged and the spinal cord is not affected. In these situations, the individual may not experience paralysis after the bones are stabilized.

The spinal cord is the major bundle of nerves that carries nerve impulses to and from the brain to the rest of the body. The brain and the spinal cord constitute the central nervous system. Motor and sensory nerves outside the central nervous system constitute the peripheral nervous system. Another diffuse system of nerves that controls involuntary functions, such as blood pressure and temperature regulation, are called the sympathetic and parasympathetic nervous systems.

The spinal cord is about 18 inches long and extends from the base of the brain, down the middle of the back, to about the waist. The nerves that lie within the spinal cord are upper motor neurons (UMNs), and their function is to carry the messages back and forth from the brain to the spinal nerves along the spinal tract. The spinal nerves that branch out from the spinal cord to the other parts of the body are called lower motor neurons (LMNs).

These spinal nerves exit and enter at each vertebral level and communicate with specific areas of the body. The sensory portions of the LMN carry messages about sensation from the skin and other body parts and organs to the brain. The motor portions of the LMN send messages from the brain to the various body parts to initiate actions such as muscle movement.

The spinal cord is surrounded by rings of bone called vertebra. These bones constitute the spinal column (back bones). In general, the higher in the spinal column the injury occurs, the more dysfunction a person will experience. The vertebra are named according to their location. The eight vertebra in the neck are called the cervical vertebra. The top vertebra is called C-1, the next is C-2, etc. Cervical spinal cord injuries usually cause loss of function in the arms and legs, resulting in quadriplegia. The 12 vertebra in the chest are called the thoracic vertebra. The first thoracic vertebra, T-1, is the vertebra where the top rib attaches.

Injuries in the thoracic region usually affect the chest and the legs, resulting in paraplegia. The vertebra in the lower back between the thoracic vertebra, where the ribs attach, and the pelvis (hip bone), are the lumbar vertebra. The sacral vertebra run from the pelvis to the end of the spinal column. Injuries to the five lumbar vertebra (L-1 thru L-5) and similarly to the five sacral vertebra (S-1 thru S-5) generally result in some loss of function in the hips and legs.

Spinal cord injuries can be divided into two types of injury complete and incomplete:

The level of injury to the spinal cord is helpful in predicting what parts of the body might be affected by paralysis and loss of function. Remember that in incomplete injuries, there will be some variation in these prognoses.

Cervical (neck) injuries usually result in quadriplegia. Injuries above the C-4 level may require a ventilator for the person to breathe. C-5 injuries often result in shoulder and biceps control, but no control at the wrist or hand. C-6 injuries generally yield wrist control, but no hand function.

Individuals with C-7 and T-1 injuries can straighten their arms, but still may have dexterity problems with the hand and fingers. Injuries at the thoracic level and below result in paraplegia, with the hands not affected. At T-1 to T-8, there is most often control of the hands, but poor trunk control resulting from a lack of abdominal muscle control. Lower thoracic injuries (T-9 to T-12) allow good trunk control and good abdominal muscle control. Sitting balance is very good. Lumbar and sacral spinal cord injuries yield decreasing control of the hip flexors and legs.

Besides a loss of sensation or motor function, individuals with spinal cord injury also experience other changes. For example, they may experience dysfunction of the bowel and bladder. Very high injuries (C-1, C-2) can result in a loss of many involuntary functions, including the ability to breathe, necessitating breathing aids such as mechanical ventilators or diaphragmatic pacemakers.

Other effects of spinal cord injury may include low blood pressure, inability to regulate blood pressure effectively, reduced control of body temperature, inability to sweat below the level of injury and chronic pain.

About 285,000 people in the United State are living with spinal cord injuries (SCIs). There are about 17,500 new SCIs every year, and the majority of them (81 percent) involve males. These injuries result from motor vehicle accidents (38.4 percent), falls (30.5 percent), violence (13.5 percent) and sports-related accidents (8.9 percent). Quadriplegia is slightly more common than paraplegia.

Currently, there is no cure for spinal cord injury. There are researchers studying this problem, and there have been many advances in the lab.

Many of the most exciting advances have resulted in a decrease in damage at the time of the injury. Steroid drugs, such as methylprednisolone, reduce swelling, which is a common cause of secondary damage at the time of injury.

When a spinal cord injury occurs, there is usually swelling of the spinal cord. This may cause changes in virtually every system in the body. After days or weeks, the swelling begins to go down, and people may regain some functioning. With many injuries, especially incomplete ones, the individual may recover some function as late as 18 months after the injury. In very rare cases, people with spinal cord injurywill regain some functioning years after the injury. However, only a small fraction of individuals sustaining a spinal cord injury recover all function.

No, not everyone who has a spinal cord injury will need to use a wheelchair. Wheelchairs are a tool for mobility. High C-level injuries usually require the individual to use a power wheelchair. Low C-level injuries and below usually allow the person to use a manual chair. Advantages of manual chairs are that they cost less, weigh less, disassemble into smaller pieces and are more agile. However, for the person who needs a power chair, the independence afforded by the chair is worth the limitations.

Some people are able to use braces and crutches for ambulation. These methods of mobility do not mean the person will never use a wheelchair. Many people who use braces still find wheelchairs more useful for longer distances. However, the therapeutic and activity levels allowed by standing or walking briefly may make braces a reasonable alternative for some people.

Of course, people who use wheelchairs aren't always in them. They drive, swim, fly planes, ski and do many activities out of their chair. If you hang around people who use wheelchairs long enough, you may see them sitting in the grass pulling weeds, sitting on your couch, or playing on the floor with children or pets. And, of course, people who use wheelchairs don't sleep in them; they sleep in a bed.

The life expectancy of someone with a spinal cord injury can vary depending on level of injury.Overall, 85 percent of people with spinal cord injury who survive the first 24 hours are still alive 10 years later. The most common cause of death is due to diseases of the respiratory system, with most of these being due to pneumonia. In fact, pneumonia is the single leading cause of death throughout the entire 15-year period immediately following SCI for all age groups, both males and females, whites and non-whites, and people with quadriplegia.

Long-term data collected by Shepherd Center and the Spinal Cord Injury Model Systems (SCIMS) show an increase in life expectancy for people who have lived 25 years or more with spinal cord injury. The survival rate at 25 or more years after injury is 60 percent; this number has been climbing steadily over the years. In addition, many of the leading indicators show the quality of that extended life expectancy is good.

Before World War II, most people who sustained a spinal cord injury died within weeks of their injury from urinary dysfunction, respiratory infection or bedsores. With the advent of modern antibiotics, modern materials such as plastics and latex, and better procedures for dealing with the everyday issues of living with SCI, many people approach the lifespan of non-disabled individuals.

Interestingly, other than level of injury, the type of rehabilitation facility used is the greatest indicator of long-term survival. This illustrates the importance of and difference made by going to a facility that specializes in spinal cord injury. People who use ventilators are at some increased danger of dying from pneumonia or respiratory infection, but modern technology is improving in that area as well. Pressure sores are another common cause of hospitalization and if not treated, can be fatal.

The second leading cause of death is infectious and parasitic diseases. These are usually cases of septicemia and are usually associated with decubitus ulcers, urinary tract infections or respiratory infections. Cancer ranked as the third leading cause of death, followed by hypertensive and ischemic heart disease.

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Spinal Cord Injury Information: Levels, Causes, Recovery