Spinal cord injury
Spinal cord injury (SCI) is damage to the spinal cord that results in a loss of function such as mobility or feeling. The spinal cord does not have to be severed in order for a loss of function to occur. In most SCI cases, the spinal cord is intact, but the damage to it results in loss of function.
The spinal cord and the brain are the two components of the central nervous system (CNS). The spinal cord extends from the base of the brain, down the middle of the back, to the lower back, and it coordinates movement and sensation in the body. It contains nerve cells, supporting cells, and long nerve fibers (axons) that connect to the brain and carry signals downward from the brain along descending pathways and upward to the brain along ascending pathways. Axons are covered by sheaths of an insulating whitish substance called myelin, and the region in which they lie is accordingly called white matter. The nerve cells themselves, with long branches (dendrites) that receive signals from other nerve cells, make up the gray matter that lies in a butterfly-shaped region in the center of the spinal cord. Like the brain, the spinal cord is enclosed in three membranes (meninges). The innermost layer is called the pia mater, the middle layer is the arachnoid, and the dura mater is the tougher outer layer. The spinal cord consists of several segments along its length, with higher segments controlling movement and sensation in upper parts of the body and lower segments controlling the lower parts of the body. The segments in the neck (cervical region), referred to as C1 to C8, control signals to the neck, arms, and hands. Those in the thoracic or upper back region (T1 to T12) control signals to the torso and some parts of the arms. Those in the mid-back (upper lumbar region) just below the ribs (L1 to L5) control signals to the hips and legs. Finally, the sacral segments (S1 to S5) lie just below the lumbar segments in the mid-back and control signals to the groin, toes, and some parts of the legs.
The types of disability associated with SCI thus depend directly on the type and severity of the injury, the level of the cord at which the injury occurs, and the nerve fiber pathways that are damaged. Severe injury to the spinal cord causes paralysis and complete loss of sensation to the parts of the body controlled by the spinal cord segments below the point of injury. Spinal cord injuries also can lead to many complications, including pressure sores and increased susceptibility to respiratory diseases.
According to the National Institute of Neurological Disorders and Stroke (NINDS), accidents and violence cause an estimated 10,000 spinal cord injuries each year, and more than 200,000 Americans live day-to-day with the disabling effects of SCI. The incidence of spinal cord injuries peaks among people in their early 20s, with a small increase in the elderly population due to falls and degenerative diseases of the spine. SCI is an uncommon source of morbidity and mortality in children.
Causes and symptoms
According to the National Spinal Cord Injury Association (NSCIA), spinal cord injuries are caused in the United States by motor vehicle accidents (44%), acts of violence (24%), falls (22%), sports (8%), and other causes (2%) such as abscesses, tumors, polio , spina bifida and Friedrich's Ataxia, a rare inherited disorder. For infants, motor vehicle crash is the leading cause of SCI. Falls rank highest for ages two to nine years and sports for the 10 to 14 age group. The most common injury level for the five to 13 age group is the high cervical spine (C1-C4).
SCI symptoms usually appear immediately after the injury. However, symptoms can develop slowly, if an infection or tumor is gradually increasing pressure on the spinal cord. General symptoms are as follows:
- weakness, poor coordination or paralysis, particularly below the level of the injury
- numbness , tingling, or loss of sensation
- loss of bowel or bladder control
When to call the doctor
Immediate medical attention is required if a parent suspects a child may have injured his or her neck or back, or if a child has poor coordination or paralysis in any part of the body. Spinal cord injury is not always obvious: numbness or paralysis may result immediately after SCI or later on as swelling gradually occurs in or around the spinal cord. In either case, the time between injury and treatment is critical and can significantly influence the extent of complications and the level of recovery. Any child who has experienced significant trauma to the head, back, or neck should be medically evaluated for the possibility of SCI.
The possibility of SCI is usually suspected in anyone with significant trauma to the head and/or neck. Physicians accordingly assume that such patients have a spine fracture until proven otherwise.
Diagnosis is established with the help of x-rays of the spine that allow doctors to determine the extent of the damage. The following imaging tests are also used: CT scan ( computed tomography ), MRI ( magnetic resonance imaging ), and myelogram (x ray after injection of dye into the spinal canal).
A person suspected of having a spinal cord injury should not be moved and treatment of SCI begins with immobilization , commonly achieved by enclosing the cervical spine in a rigid collar and use of rigid backboards. Paramedics and other rescue workers receive extensive training in immobilizing the spine. Immobilization prevents further injuries to the cord at the scene of the injury and has helped reduce worsening of any neurological SCI injury. At the time of injury, treatment is focused on stabilizing the spine and relieving cord compression. Prompt steroid drug injections (within eight hours of the injury) are also used to minimize cell damage and improve the chance of recovery.
Surgery cannot reverse damage to the spinal cord but is often needed to stabilize the spine to prevent future pain or deformity. It may involve fusing together vertebrae or inserting metal pins; or removing bone chips, bullets, or other foreign objects ; or draining fluid to relieve pressure. Long-term treatment of spinal cord injuries usually involves drug therapy, the use of neural prostheses, and rehabilitation. Complementary treatment includes nutrition management, psychological counseling, and careful monitoring by physicians.
Effective drug therapy for spinal cord injury was demonstrated in 1990, when methylprednisolone, the first drug shown to improve recovery from spinal cord injury, was approved for standard use. Completely paralyzed patients given methylprednisolone recover an average of about 20 percent of their lost motor function, compared to only 8 percent recovery of function in untreated patients. Partially paralyzed patients recover an average of 75 percent of their function, compared to 59 percent in patients who do not receive the drug.
Neural prostheses are used to compensate for lost function resulting from SCI. These sophisticated electrical and mechanical devices connect with the nervous system to supplement or replace lost motor and sensory functions. Neural prostheses contain many intricate components, such as implanted stimulators, electrodes, leads and connectors, sensors, and programming systems. There are many technical considerations in selecting each component. The electronic components must be as small as possible. Biocompatibility between electrodes and body tissue is also required to prevent the patient from being harmed by contact with the device. One device, a neural prosthesis that allows rudimentary hand control, was approved by the United States Food and Drug Administration (FDA). Patients control the device using shoulder muscles. With training, most patients can open and close their hand in two different grasping movements and lock the grasp in place by moving their shoulder in different ways.
Rehabilitation techniques can greatly improve patients' health and quality of life by helping them learn to use their remaining abilities. They start by setting functional goals. Functional goals are a realistic expectation of activities that a person with SCI eventually should be able to do with a particular level of injury. These goals are set during rehabilitation with the medical team. They help the patient with SCI learn new ways to manage his/her daily activities and stay healthy. Developing independence is especially important to kids, particularly teenagers. Many hospitals have SCI units geared to help patients develop their independence, and SCI treatment centers are operational in several states with special programs for children. The SCI units include kitchens and laundry facilities and other equipment so that patients can learn independent living skills, such as cooking meals or ironing clothes. A spinal cord injury can also affect the nerves and muscles and can cause bowel and bladder problems and skin problems. Children are prepared for these changes during rehabilitation and are taught the self-care skills needed to deal with these problems. Parents of spinal cord injured children also need to learn how to take care of their spinal-cord injured child. Having a spinal cord injury does not mean that children have to stop participating in games and enjoyable activities. Most SCI units have recreational therapists on staff to show kids how to play wheelchair basketball, volleyball, and tennis, as well as specially adapted games.
People with spinal cord injuries caused by traumatic events have in the past been considered hopeless cases destined to a life of paralysis. But in the last decades of the twentieth century there were dramatic advances in spinal cord regeneration research. For example, Swiss scientist Martin Schwab actually managed to heal spinal cords in rats and restored their ability to walk. At the Swedish Karolinska Institute, scientists succeeded in constructing a bridge of slender nerve filaments to connect a once-severed spinal cord in rats that subsequently were able to flex their legs. These developments and others offer paralyzed people some hope. In the early 2000s envisioned treatments include an immune therapy procedure that has been tested in Israel with human subjects and possibilities for mechanical neural prostheses.
Acupuncture is a more conservative form of alternative treatment with documented evidence for the reduction of SCI-related muscle spasms , increased level of sensation, improved bladder and bowel function, improvement in lower limb paralysis, with younger patients reported to have better outcomes.
Because of the changes that occur in the body after SCI, parents need to understand the role that nutrition can play in the overall health of a child following a spinal cord injury.
Special health concerns resulting from SCI are as follows:
- Bowel management. Individuals with SCI may have neurogenic bowel, with the result that the messages from the brain that control the downward muscular movements of the bowel are either absent or not working properly, making it difficult for stool to move through the intestines. SCI diets accordingly include high fiber and plenty of fluids to regulate bowel movements.
- Heart problems. SCI presents a greater risk for cardiovascular and heart problems, hence the necessity to limit salt and cholesterol intake.
- Pressure ulcers. Pressure ulcers are always a concern to individuals with SCI and a diet high in protein, vitamins , and minerals is recommended to promote skin healing.
- Kidney or bladder stones. Individuals with SCI may be prone to developing calcium stones. Certain beverages can cause crystals to form in the urine and excessive consumption of dairy products is accordingly avoided with water highly recommended as the best drink.
- Urinary tract infection. The loss of normal bladder function after SCI places an individual at risk for urinary tract infection. A high fluid intake every day has been shown to reduce the problem of infections.
- Weight control. After SCI, the metabolic rate is usually lower. Metabolic rate is how fast a body burns ingested calories. A lower muscle mass and a decrease in activities cause a lower metabolic rate, meaning that fewer calories are needed each day to maintain a desirable weight. After rehabilitation, the ideal body weight of a person with SCI is lower than for a nondisabled individual. Dieticians normally decrease the amount of calories by 5 percent for those with paraplegia and 10 to 15 percent for those with tetraplegia (quadriplegia).
The prognosis of SCI depends on the location and extent of injury. Once the initial injury heals, functional improvements may continue for at least six months. Any disability that remains after that point is likely to be permanent. Injuries of the neck above C4 with significant involvement of the diaphragm have worse outcomes. Although SCI often results in permanent disability, rehabilitation can maximize the level of function and help patients adapt and lead independent, productive lives.
According to the American Association of Neurological Surgeons, mortality from SCI is influenced by several factors, the most important being the severity of associated injuries. Because of the force that is required to fracture the spine, it is not uncommon for the patient to suffer significant damage to the chest and/or abdomen. Many of these associated injuries are fatal. For isolated SCIs, the mortality after one year is roughly 5 to 7 percent. If a patient survives the first 24 hours after injury, the probability of survival for ten years is approximately 75 to 80 percent. Likewise, the ten-year survival rate for patients who survived the first year after injury is 87 percent.
The following guidelines have been shown to help prevent SCI:
- use of safe driving practices
- avoidance of situations that may become violent
- keeping firearms locked away
- taking precautions to prevent falls around the home (walkways free from obstacles, non-slip materials in bathtubs, etc)
- use of proper safety equipment for sports
The American Academy of Orthopedic Surgeons (AAOS) also recommends that playgrounds be made safe to prevent spinal cord injuries. It offers the following checklist to help parents assess the safety of their child's playground:
- Are any pieces of playground equipment missing supports, anchors, or footings?
- Are any supports, anchors, or footings damaged or loose?
- Has the wood started to splinter or rot?
- Are surface materials missing or damaged?
- Are there any missing, loose, or damaged nuts and bolts on the equipment?
- Are any seats broken?
- Are swing hangers and chains broken or worn?
- Are hooks, rings, or links misshapen or deformed?
- Are there any broken, missing, or loose steps?
- Are any ladder rungs missing, broken, or loose?
- Are tree roots visible or rocks sticking up that could cause a child to trip and fall?
If the answer to any of these questions is "Yes," this playground is not safe for a child. The AAOS recommends that the playground be reported to local park or school officials or to contact a local orthopedic surgeon to enquire as how to build a safe, accessible playground for the area.
In most cases, SCI requires that the home be modified to be fully accessible to the injured child. Bathrooms need to be fitted with a shower chair, grab bars, a shower wand, a tub lift, or a shower bench. Grab bars should be installed on three sides of the shower, and non-skid strips should be applied to the bottom of the shower or tub. Bedrooms should be located for convenient access to the bathroom and adequate space should be provided around the bed for wheelchair access with convenient storage near the bed for braces, prostheses, and clothing. Light switches should be lowered for easy access and ramps should be built to facilitate displacements.
Axon —A long, threadlike projection that is part of a neuron (nerve cell).
Central nervous system —Part of the nervous system consisting of the brain, cranial nerves, and spinal cord. The brain is the center of higher processes, such as thought and emotion and is responsible for the coordination and control of bodily activities and the interpretation of information from the senses. The cranial nerves and spinal cord link the brain to the peripheral nervous system, that is the nerves present in the rest of body.
Computed tomography (CT) —An imaging technique in which cross-sectional x rays of the body are compiled to create a three-dimensional image of the body's internal structures; also called computed axial tomography.
Dendrite —A threadlike extension of the cytoplasm of a neuron that conducts electrical impulses toward the cell body of the neuron. Usually it spreads out into many branches..
Gray matter —Areas of the brain and spinal cord that are comprised mostly of unmyelinated nerves.
Magnetic resonance imaging (MRI) —An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct detailed images of internal body structures and organs, including the brain.
Methylpredisolone —A steroid drug. Methylpredisolone administered within eight hours of acute spinal cord trauma is the first drug shown to improve recovery from spinal cord injury.
Myelin —A fatty sheath surrounding nerves throughout the body that helps them conduct impulses more quickly.
Myelogram —An x-ray image of the spinal cord, spinal canal, and nerve roots taken with the aid of a contrast dye.
Spina bifida —A birth defect (a congenital malformation) in which part of the vertebrae fail to develop completely so that a portion of the spinal cord, which is normally protected within the vertebral column, is exposed. People with spina bifida can suffer from bladder and bowel incontinence, cognitive (learning) problems, and limited mobility.
Vertebrae —Singular, vertebra. The individual bones of the spinal column that are stacked on top of each other. There is a hole in the center of each bone, through which the spinal cord passes.
White matter —A substance, composed primarily of myelin fibers, found in the brain and nervous system that protects nerves and allows messages to be sent to and from the brain and various parts of the body. Also called white substance.
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Monique Laberge, Ph.D.