Spinal Cord Injury
What is it?
Spinal cord injury (SCI) occurs when the spinal cord is damaged in a way that results in some loss of sensation and motor control. The spinal cord is a thick length of nerve tissue that extends from the base of the brain, down the back, through the spinal column. The spinal column is made up of bones called vertebrae that protect the spinal cord. The spinal cord is made up of motor and sensory nerve cells called neurons. The motor nerves are grouped together and transmit motor commands from the brain to the muscles and initiate movement. The sensory nerves are also grouped together. They carry information about sensations, such as pain and temperature, to the brain. The spinal cord is divided into four areas: cervical (neck), thoracic (chest), lumbar (lower back), and sacral (tailbone). Each area is referred to by its first letter (C, T, L, or S) and the vertebrae within each area of the spine are numbered as follows:
- C1 to C8: Cervical vertebrae
- T1 to T12: Thoracic vertebrae
- L1 to L5: Lumbar vertebrae
- S1 to S5: Sacral vertebrae
The nerves enter and exit the spinal cord through the small openings between each vertebra. The nerves that enter through the tailbone (coccyx) are called coccygeal nerves. Spinal cord injuries occur most often in the areas of C5 to C7, and T10 to L2, where the spine is most flexible. When injured, each spinal area has distinct symptoms that help doctors pinpoint the nerves that are damaged.
Who gets it?
Approximately 10,000 people injure their spinal cord in the United States each year. Spinal cord injuries can happen to anyone, at any age. However, men between the ages of 19 and 26 are more likely to have a spinal cord injury due to an accident or some act of violence.
What causes it?
Damage to the spinal cord is usually caused by one of five different types of injuries. Concussion of the spinal cord occurs when a sudden, violent jolt injures the tissues around the cord. This injury is usually temporary and goes away with in a few hours. A spinal contusion (bruise) causes bleeding to occur in the spinal column. The pressure the bleeding puts on the spinal cord can kill neurons. Spinal compression occurs when an object, for example, a tumor, puts pressure on the spinal cord. When the spinal cord becomes torn by some type of injury, the neurons are also damaged. Or, injury occurs when the spinal cord is completely cut. Fifty percent of all spinal cord injuries occur in a motor vehicle accident. Twenty percent occur from a fall, 15% from some act of violence, and 14% from a sports-related accident. The accidents that cause many spinal cord injuries are related to drug or alcohol abuse. Other causes of spinal cord injury include infection or disease, such as cysts on the spinal cord, multiple sclerosis, or cervical spondylosis (degeneration of the disks and vertebrae in the neck).
What are the symptoms?
Damage to the spinal cord interrupts the signals from the sensory and motor nerves, resulting in varying degrees of paralysis and loss of sensation. Symptoms depend upon the severity and location of the injury. A completely severed spinal cord causes paralysis and loss of sensation below the severed section. Patients with the cord partially severed may have some function below the injury. Damage to the front portion of the cord causes paralysis and loss of the ability to feel pain and changes in temperature. Damage to the center of the cord may paralyze the arms, but not the legs. Damage to the right or left half of the spinal cord causes paralysis on the side of the injury, loss of pain and temperature sensation on the opposite side of the injury, and loss of the ability to sense position. Injuries located in vertebrae C1 to C5 may cause paralysis of the muscles used for breathing and all arm and leg muscles. Theses types of injuries usually result in death. Damage above the T1 vertebra affects the arms and the legs. Injuries below the T1 vertebra affect the legs and trunk below the injury, but usually do not affect the arms and hands. Paralysis of the legs is called paraplegia. Paralysis of the arms and legs is called quadriplegia. Complications of spinal cord injuries include deep vein thrombosis, in which lack of normal blood flow to the paralyzed area causes blood to pool in the deep veins and form clots; pressure ulcers of the skin from staying in one position for long periods of time; joint deformity caused by the constant contraction of the muscle (contracture); abnormal deposits of bone in muscles and tendons, called heterotopic ossification; and urinary infection and hardened stool in the large intestine and rectum (impaction) from the loss of bladder and bowel control. Patients with paralysis are unable to sense when they might have an over-full bladder or bladder infection, constipation or impaction, or skin irritation. When this happens, the nerves respond by releasing high amounts of norepinephrine, which is a hormone similar to adrenaline. This causes the blood pressure to rise rapidly and the heart rate to slow. The signs of this condition, called autonomic dysreflexia, include throbbing headache, nausea, anxiety, sweating, and goose bumps below the level of the spinal injury. If untreated, it can result in unconsciousness, seizures, cerebral hemorrhage, and death. While men who are paralyzed below the waist area lose sexual function, women who are paralyzed may still be able to become pregnant and deliver vaginally with close medical supervision.
How is it diagnosed?
Because the nerves control feeling and movement in specific parts of the body, the symptoms of a spinal cord injury tell a doctor exactly where the injury occurred. In addition to a complete physical exam and study of symptoms, diagnostic tests such as x-rays, computed tomography scans (CT scans), and magnetic resonance imaging (MRI) scans of the spinal area can help pinpoint the location and severity of the injury. A myelogram is special type of x-ray in which a dye is injected around the spinal cord. When the x-ray is taken, the dye will look pinched off in the area of the spinal injury. If the symptoms are caused by a tumor compressing the spinal cord, the doctor may take a biopsy (tissue sample) of the growth to determine if it is cancerous.
What is the treatment?
People with spinal cord injuries are strapped to a firm board before being moved to a hospital. Movement without this precaution can completely sever the cord. A drug called methylprednisone, which is a steroid-type anti-inflammatory drug, is given intravenously during the first 24 hours to help reduce inflammation and swelling, and the destruction of tissue around the spinal cord. If blood has accumulated around the spinal cord, it will be removed to reduce pressure on the area. Surgeons may also insert steel rods around the spinal column to stabilize it. A compressed spinal cord is treated by removing the cause of the compression through surgery or radiation therapy. If the compression is caused by an infection, it is treated with antibiotics and draining the abscess, which is the source of infection. When spinal cord injury causes paralysis and loss of sensation, treatment is aimed at rehabilitating the patient to help him or her regain as much function as possible. Rehabilitation after spinal injury requires a great deal of support and patience, and involves a team that might include neurologists, rehabilitation specialists, physical therapists, occupational therapists, respiratory therapists, social workers, speech therapists, nutritionists, special education teachers, recreation therapists, and clinical psychologists. Complications of paralysis, such as pressure ulcers, can be prevented by making sure the patient is turned frequently in bed. A regular program of physical therapy that includes range of motion exercises can help prevent muscle contracture. In severe cases, surgery may be necessary to cut the shortened tendon and release the contracture. In cases where heterotopic ossification is a problem, the patient is given a drug containing etidronate disodium to help to regulate the body’s calcium use. It is extremely important to pay close attention to bowel and bladder care for patients with spinal cord injuries. Keeping the area clean can help prevent autonomic dysreflexia. Patients who have lost bowel control may require stimulation through pressure on the abdomen to help move the bowels. Patients with loss of bladder control may need to be catheterized by inserting a thin tube through the urethra to the bladder to drain urine into a collecting bag. It is important to provide the patient with sufficient fluids and a fiber-rich diet. Research has found that paraplegic patients may respond to electrical stimulation of the muscles. This approach is still experimental, but may offer some the ability to walk without assistance. 85% of patients with spinal cord injuries who survive the first 24 hours are alive 10 years later. The amount of function that can be recovered depends upon the location and severity of the injury.
Self-care tips
You can lower your risk of spinal cord injury by taking steps to prevent accidents that can cause this type of injury. Never dive into water unless you are sure of its depth, drive safely, wear a seat belt, and avoid using drugs or alcohol, especially when driving or participating in recreational activities.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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