Spinal Cord Injury
According to the Centers for Diseases Control and Prevention (CDC), SCI costs the nation an estimated $9.7 billion each year. Pressure sores alone, a common secondary condition among people with SCI, cost an estimated $1.2 billion.
Incidence
• The incidence of spinal cord injury is highest among persons age 16-30, in whom 53.1 percent of injuries occur; more injuries occur in this age group than in all other age groups combined.
• Males represent 81.2 percent of all reported spinal cord injuries and 89.8 percent of all sports-related SCIs.
• Among both genders, auto accidents, falls and gunshots are the three leading causes of spinal cord injury, in that order. Among males, diving accidents ranked fourth, followed by motorcycle accidents. Among females, medical/surgical complications ranked fourth, followed by diving accidents.
• Auto accidents are the leading cause of spinal cord injury in the United States for people age 65 and younger, while falls are the leading cause of SCI for people 65 and older.
• Sports and recreation-related SCI injuries primarily affect people under age 29.
The Spinal Cord
The spinal cord is about 18 inches long, extending from the base of the brain
to near the waist. Many of the bundles of nerve fibers that make up the spinal
cord itself contain upper motor neurons (UMNs). Spinal nerves that branch off
the spinal cord at regular intervals in the neck and back contain lower motor
neurons (LMNs). The spine itself is divided into four sections, not including
the tailbone:
• Cervical vertebrae (1-7), located in the neck
• Thoracic vertebrae (1-12), in the upper back (attached to the ribcage)
• Lumbar vertebrae (1-5), in the lower back
• Sacral vertebrae (1-5), in the pelvis
Types and Levels of SCI
The severity of an injury depends on the part of the spinal cord that is affected.
The higher the spinal cord injury on the vertebral column, or the closer it is to the brain,
the more effect it has on how the body moves and what one can feel. More movement,
feeling and voluntary control are generally present with injuries at lower levels.
• Tetraplegia (a.k.a. quadriplegia) results from injuries to the spinal cord in the cervical (neck) region, with associated loss of muscle strength in all four extremities.
• Paraplegia results from injuries to the spinal cord in the thoracic or lumbar areas, resulting in paralysis of the legs and lower part of the body.
Complete SCI
A complete spinal cord injury produces total loss of all motor and sensory function below the
level of injury. Nearly 50 percent of all spinal cord injuries are complete. Both sides of the
body are equally affected. Even with a complete SCI, the spinal cord is rarely
cut or transected. More commonly, loss of function is caused by a contusion
or bruise to the spinal cord or by compromise of blood flow to the injured part
of the spinal cord.
Incomplete SCI
In an incomplete spinal cord injury, some function remains below the primary level of the injury.
A person with an incomplete injury may be able to move one arm or leg more than
the other, or may have more functioning on one side of the body than the other.
An incomplete SCI often falls into one of several patterns.
Anterior cord syndrome results from injury to the motor and sensory pathways in the anterior parts of the spinal cord. These patients can feel some types of crude sensation via the intact pathways in the posterior part of the spinal cord, but movement and more detailed sensation are lost.
Central cord syndrome usually results from trauma and is associated with damage to the large nerve fibers that carry information directly from the cerebral cortex to the spinal cord. Symptoms may include paralysis and/or loss of fine control of movements in the arms and hands, with far less impairment of leg movements. Sensory loss below the site of the spinal cord injury and loss of bladder control may also occur, with the overall amount and type of functional loss related to the severity of damage to the nerves of the spinal cord.
Brown-Sequard syndrome is a rare spinal disorder that results from an injury to one side of the spinal cord. It is usually caused by an injury to the spine in the region of the neck or back. In many cases, some type of puncture wound in the neck or in the back that damages the spine may be the cause. Movement and some types of sensation are lost below the level of injury on the injured side. Pain and temperature sensation are lost on the side of the body opposite the injury because these pathways cross to the opposite side shortly after they enter the spinal cord.
Injuries to a specific nerve root may occur either by themselves or together with a spinal cord injury. Because each nerve root supplies motor and sensory function to a different part of the body, the symptoms produced by this injury depend upon the pattern of distribution of the specific nerve root involved.
"Spinal concussions" can also occur. These can be complete or incomplete, but spinal cord dysfunction is transient, generally resolving within one or two days. Football players are especially susceptible to spinal concussions and spinal cord contusions. The latter may produce neurological symptoms including numbness, tingling, electric shock-like sensations, and burning in the extremities. Fracture-dislocations with ligamentous tears may be present in this syndrome.
Penetrating Spinal Cord Injury
"Open" or penetrating injuries to the spine and spinal cord, especially those
caused by firearms, may present somewhat different challenges. Most gunshot
wounds to the spine are stable, i.e., they do not carry as much risk of excessive
and potentially dangerous motion of the injured parts of the spine. Depending
upon the anatomy of the injury, the patient may need to be immobilized with
a collar or brace for several weeks or months so that the parts of the spine
that were fractured by the bullet may heal. In most cases, surgery to remove
the bullet does not yield much benefit and may create additional risks, including
infection, cerebrospinal fluid leak, and bleeding. However, occasional cases
of gunshot wounds to the spine may require surgical decompression and/or fusion
in an attempt to optimize patient outcome.
NeurosurgeryToday.org
November, 2005
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