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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.
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.
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.
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
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 |
