1. What is 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. Frequent causes of damage are trauma (car accident, gunshot, falls, etc.) or disease (polio, spina bifida, Friedreich’s Ataxia, etc.). The spinal cord does not have to be severed in order for a loss of functioning to occur. In fact, in most people with SCI, the spinal cord is intact, but the damage to it results in loss of functioning. SCI 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, but the spinal cord is not affected. In these situations, the individual may not experience paralysis after the bones are stabilized.
2. What is the Spinal Cord and the Vertebra?
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 the major bundle of nerves that carry 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, and another diffuse system of nerves that control involuntary functions such as blood pressure and temperature regulation are the Sympathetic and Parasympathetic Nervous Systems.
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 SCI’s usually cause loss of function in the arms and legs, resulting in quadriplegia. The twelve 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 and result 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 functioning in the hips and legs.
What are the effects of SCI? The effects of SCI depend on the type of injury and the level of the injury. SCI can be divided into two types of injury – complete and incomplete. A complete injury means that there is no function below the level of the injury; no sensation and no voluntary movement. Both sides of the body are equally affected. An incomplete injury means that there is some functioning below the primary level of the injury. A person with an incomplete injury may be able to move one limb more than another, 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. With the advances in acute treatment of SCI, incomplete injuries are becoming more common.
The level of injury is very 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 as the result of lack of abdominal muscle control. Lower T-injuries (T-9 to T-12) allow good truck control and good abdominal muscle control. Sitting balance is very good. Lumbar and Sacral injuries yield decreasing control of the hip flexors and legs.
Besides a loss of sensation or motor functioning, individuals with SCI also experience other changes. For example, they may experience dysfunction of the bowel and bladder,. Sexual functioning is frequently with SCI may have their fertility affected, while women’s fertility is generally not affected. 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 SCI 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.
3. What is Spinal Stenosis?
The spinal canal is like a tunnel which runs up and down the human spine. This canal sits directly behind the bony blocks which make up the spine (vertebrae) and contains the nerves (spinal cord and nerve roots) running from the brain to all areas of the body
When something causes a narrowing of this canal then the nerves can become irritated or squeezed. This can lead to a variety of symptoms ranging from tingling, numbness, and weakness to severe pain and paralysis. Common conditions which can narrow the spinal canal include a herniated disc (often called a slipped disc), fracture of the spine, tumor, infection and degeneration. A set of symptoms related to narrowing of the spinal canal seen with aging and degeneration is called spinal stenosis. The symptoms of spinal stenosis most commonly include a sensation of heaviness, weakness and pain with walking or prolonged standing. At rest these symptoms usually disappear. These symptoms are related to the irritation of the nerves in the spinal canal which is worsened with standing or walking due to mechanical compression or stretching of the nerves. Patients often complain of a gradual decrease in their ability to walk, requiring more frequent stops to rest their legs. The treatment for spinal stenosis is dependant on the severity of symptoms. Generally, aerobic activities like walking combined with a guided exercise program and weight loss (in overweight patients) is recommended first.
When there is no relief, some specialists recommend injection treatments although the effectiveness of this is limited. Surgery is indicated when symptoms are severe, progressive and a specific area of narrowing in the spinal canal has been discovered. The surgical procedure is aimed at freeing up the nerves in the canal by removing pieces of bone and thickened tissues such as the ligaments. A spinal fusion may also be necessary to stabilize the spine
The spine consists of a series of bone blocks (vertebral bodies) which are separated from one another by discs of soft tissue. Within the structure of the spine sits a tunnel called the spinal canal. This tunnel contains the neurologic structures including the spinal cord and nerve roots. Although there is some free space between the neurologic structures and the edges of the spinal canal, this space can be reduced by many different conditions including injury to the spine. The canal is surrounded by bone and ligaments and therefore can not expand if the spinal cord or nerves require more room. Therefore, if anything begins to narrow the spinal canal, there is risk for irritation or injury of the spinal cord or nerves. Conditions which can lead to narrowing of the spinal canal include infection, tumors, trauma, herniated disc, arthritis and degeneration.
Spinal stenosis refers to the condition of neurologic problems associated with narrowing of the spinal canal due to degenerative changes in the spine. Arthritis of the small joints in the spine (facets) as well as thickening of ligaments and formation of bony spurs can all lead to gradual squeezing and irritation of neurologic structures. This process is usually gradual and can lead to symptoms such as pain with walking, a decreased endurance for physical activities, heaviness in the legs, tingling sensations, tightness and numbness in the legs with activity, and often associated low back pains.
Treatment for spinal stenosis ranges from physical therapy to epidural injections and finally surgery in certain cases. Since patients affected by spinal stenosis are usually elderly, treatment must carefully consider not only the disease in the spine but also the risks and benefits of treatment in each individual. Although therapy and steroid injections into the affected area of the spine can offer good relief in some patients, there are people who will only get temporary relief if at all. In patients who have failed non-operative treatment, surgery can sometimes be considered. Prior to designing a treatment plan for any individual, careful diagnosis must be made. This will often involve tests such as an MRI, CT scan, or myelogram and plain X-rays. In those patients who are candidates for surgery, the goal is to free up the constricted regions of the spinal canal to ensure freeing the affected neurologic structures. Occasionally, in order to stabilize a degenerated part of the spine, a fusion will be performed. This involves laying down of bone over an area of the spine so that a solid block is created where there was previously arthritis with pain and an unstable spine.
Surgery for spinal stenosis has a high success rate in patients carefully selected for this procedure. It remains a useful approach in treatment when other options have been exhausted and after careful review of risks and benefits with the patient.
4. What are the effects of SCI?
The effects of SCI depend on the type of injury and the level of the injury. SCI can be divided into two types of injury – complete and incomplete. A complete injury means that there is no function below the level of the injury; no sensation and no voluntary movement. Both sides of the body are equally affected. An incomplete injury means that there is some functioning below the primary level of the injury. A person with an incomplete injury may be able to move one limb more than another, 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. With the advances in acute treatment of SCI, incomplete injuries are becoming more common.
The level of injury is very 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 as the result of lack of abdominal muscle control. Lower T-injuries (T-9 to T-12) allow good truck control and good abdominal muscle control. Sitting balance is very good. Lumbar and Sacral injuries yield decreasing control of the hip flexors and legs.
Besides a loss of sensation or motor functioning, individuals with SCI also experience other changes. For example, they may experience dysfunction of the bowel and bladder,. Sexual functioning is frequently with SCI may have their fertility affected, while women’s fertility is generally not affected. 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 SCI 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.
5. How many people have SCI?
Approximately 450,000 people live with SCI in the US. There are about 10,000 new SCI’s every year; the majority of them (82%) involve males between the ages of 16-30. These injuries result from motor vehicle accidents (36%), violence (28.9%), or falls (21.2%).Quadriplegia is slightly more common than paraplegia.
For more information on Spinal Cord Injury visit:
Foundation for Spinal Cord Injury Prevention, Care and Cure
Spinal Cord Injury Resource Center