Overview of Spinal Cord Disorders
Causes of spinal cord disorders include injuries, infections, a blocked blood supply, and compression by a fractured bone or a tumor.
Typically, muscles are weak or paralyzed, sensation is abnormal or lost, and controlling bladder and bowel function may be difficult.
Doctors base the diagnosis on symptoms and results of a physical examination and imaging tests, such as magnetic resonance imaging.
The condition causing the spinal cord disorder is corrected if possible.
Often, rehabilitation is needed to recover as much function as possible.
The spinal cord is the main pathway of communication between the brain and the rest of the body. It is a long, fragile, tubelike structure that extends downward from the base of the brain. The cord is protected by the back bones (vertebrae) of the spine (spinal column). The vertebrae are separated and cushioned by disks made of cartilage.
Where Is the Spinal Cord Damaged?
The spine is divided into four sections, and each section is referred to by a letter.
Within each section of the spine, the vertebrae are numbered beginning at the top. These labels (letter plus a number) are used to indicate locations (levels) in the spinal cord.
Along the length of the spinal cord, 31 pairs of spinal nerves emerge through spaces between the vertebrae. Each spinal nerve runs from a specific vertebra in the spinal cord to a specific area of the body. Based on this fact, the skin’s surface has been divided into areas called dermatomes. A dermatome is an area of skin whose sensory nerves all come from a single spinal nerve root. Loss of sensation in a particular dermatome enables doctors to locate where the spinal cord is damaged.
A spinal nerve has two nerve roots (a motor root and a sensory root). The only exception is the first spinal nerve, which has no sensory root.
Motor root: The root in the front (the motor or anterior root) contains nerve fibers that carry impulses (signals) from the spinal cord to muscles to stimulate muscle movement (contraction).
Sensory root: The root in the back (the sensory or posterior root) contains nerve fibers that carry sensory information about touch, position, pain, and temperature from the body to the spinal cord.
The spinal cord ends in the lower back (around L1 or L2), but the lower spinal nerve roots continue, forming a bundle that resembles a horse’s tail (called the cauda equina—see What Is the Cauda Equina Syndrome?).
The spinal cord is highly organized (see Figure: How the Spine Is Organized). The center of the cord consists of gray matter shaped like a butterfly:
The front "wings" (anterior or motor horns) contain nerve cells that carry signals from the brain or spinal cord through the motor root to muscles.
The back (posterior or sensory) horns contain nerve cells that receive signals about pain, temperature, and other sensory information through the sensory root from nerve cells outside the spinal cord.
The outer part of the spinal cord consists of white matter that contains pathways of nerve fibers (called tracts or columns). Each tract carries a specific type of nerve signal either going to the brain (ascending tracts) or from the brain (descending tracts).
To and From and Up and Down the Spinal Cord
Some spinal cord disorders may originate outside the cord or, less commonly, inside the cord.
These disorders include fluid-filled cavities (syrinxes), blockage of the blood supply, inflammation (as occurs in acute transverse myelitis), tumors, abscesses, bleeding (hemorrhage), vitamin B12 or copper deficiency, infection with the human immunodeficiency virus (HIV), multiple sclerosis, and syphilis.
Because of the way the spinal cord functions and is organized, damage to the cord often produces specific patterns of symptoms based on where the damage occurred. The following may occur in various patterns:
Loss of sensation (such as the ability to feel a light touch, pain, temperature, or vibration or to sense where the arms and legs are)
Changes in reflexes
Loss of bladder control (urinary incontinence)
Loss of bowel control (fecal incontinence)
By identifying which functions are lost, doctors can tell which part of the spinal cord (such as the front, back, side, center, or entire cord) is damaged. By identifying the specific location of symptoms (for example, which muscles are paralyzed and which parts of the body lack sensation), doctors can determine exactly where the spinal cord is damaged (that is, the specific level in the spinal cord).
Functions may be completely or partially lost. Functions controlled by areas of the spinal cord above the damage are not affected.
When weakness or paralysis occurs suddenly, muscles go limp (flaccid), losing their tone. After muscles become flaccid, muscle tone eventually increases and muscles tend to contract involuntarily (called spasms, or spasticity).
When disorders (such as cervical spondylosis and hereditary spastic paraparesis) slowly damage the spinal cord, they can cause paralysis with increased muscle tone and muscle spasms (called spastic paralysis).
Spasms can occur because signals from the brain cannot pass through the damaged area to help control some reflexes. As a result, the reflexes become more pronounced over days to weeks. Then, the muscles controlled by the reflex may tighten, feel hard, and twitch uncontrollably from time to time.
Often, doctors can recognize a spinal cord disorder based on its characteristic pattern of symptoms. Doctors always do a physical examination, which provides clues to the diagnosis and, if the spinal cord is damaged, helps doctors determine where the damage is. An imaging test is done to confirm the diagnosis and determine the cause.
Magnetic resonance imaging (MRI) is the most accurate imaging test for spinal cord disorders. MRI shows the spinal cord, as well as abnormalities in the soft tissues around the cord (such as abscesses, hematomas, tumors, and ruptured disks) and in bone (such as tumors, fractures, and cervical spondylosis). If MRI is not available, myelography with computed tomography (CT) is used. For myelography with CT, CT is done after a radiopaque contrast agent is (dye) injected into the space around the spinal cord.
X-rays may be done to check for problems with the spine, such as fracture or tumors.
If symptoms of spinal cord dysfunction (such as paralysis or loss of sensation) suddenly occur, people should immediately go to the emergency department. Sometimes doing so can prevent permanent nerve damage or paralysis. If possible, the cause is treated or corrected. However, such treatment is often impossible or unsuccessful.
People who are paralyzed or confined to bed because of a spinal cord disorder require skilled nursing care to prevent complications, which include the following:
Pressure sores: Nurses inspect the person's skin daily, keep the skin dry and clean, and turn the person frequently. When necessary, a special bed called a Stryker frame is used. It can be turned to shift pressure on the body from front to back and from side to side.
Urinary problems: If a person is immobile and cannot use a toilet, a urinary catheter may be needed. To help reduce the risk of a urinary tract infection, nurses use sterile techniques when the catheter is inserted and apply antimicrobial ointments or solutions daily.
Pneumonia: To reduce the risk of pneumonia, therapists and nurses may teach the person deep breathing exercises. They may also place the person at an angle to help drain secretions that accumulate in the lungs (postural drainage), or they may suction secretions out.
Blood clots: Anticoagulant drugs, such as heparin or low molecular weight heparin, may be given by injection. If a person cannot take anticoagulants (for example, because of a bleeding disorder or stomach ulcers), a filter, sometimes called an umbrella (see Figure: Inferior Vena Cava Filters: One Way to Prevent Pulmonary Embolism), is inserted into the inferior vena cava (the large vein that carries blood from the abdomen to the heart). The filter traps blood clots that have broken loose from leg veins before they reach the heart.
Extensive loss of body functions can be devastating, causing depression and loss of self-esteem. Formal counseling can be very helpful. Learning exactly what has happened and what to expect in the near and distant future helps people cope with the loss and prepare them for rehabilitation.
Rehabilitation: Rehabilitation helps people recover as much function as possible. The best care is provided by a team that includes nurses, a physical therapist, an occupational therapist, a social worker, a nutritionist, a psychologist, and a counselor, as well as the person and family members. A nurse may teach the person ways to manage bladder and bowel dysfunction, such as how to insert a catheter, when to use laxatives, or how to stimulate bowel movements using a finger.
Physical therapy involves exercises for muscle strengthening and stretching. People may learn how to use assistive devices such as braces, a walker, or a wheelchair and how to manage muscle spasms.
Occupational therapy helps people relearn how to do their daily tasks and helps them improve dexterity and coordination. They learn special techniques to help compensate for lost functions. Therapists or counselors help some people make the adjustments needed to return to work and to hobbies and activities. People are taught ways to deal with sexual dysfunction. Sex is still possible for many people, even though sensation is usually lost.
Emotional support from family members and close friends is important.