Overview

Finding the pain generator
Multiple therapies, multiple choices: How to choose?
Pain Treatment Continuum

Fast Facts

• About 85% of Americans experience back pain by age 50
• Back problems are the most frequent cause of activity limitations in working-age adults
• More than 26 million Americans between the ages of 20 and 64 experience frequent back pain
• Two-thirds of American adults will have back pain during their lifetime
• Back pain is the leading cause of disability in Americans under 45 years old
• Back pain is the second most common reason why people in the United States seek medical care from their primary care physicians

Back and neck pain are the most common chronic pain conditions. Back and neck pain can arise from soft tissues, bony parts of the back and neck, and joints holding the spine in alignment. It can arise directly or indirectly from the discs in the back or neck, and it can occur when nervous tissue, normally protected by the bones of the vertebral spine, is compressed by those bony elements. The causes for such types of pain include, but are not limited to:

• Sprain and strain of the back
• Pain arising from the discs themselves; which is called discogenic pain;
• Pain from bulging discs compressing exiting nerve roots, which is called radicular pain;
• Pain from arthritis of the facet joints – joints that hold the spine in alignment – called facet joint syndrome
• Pain from bony compression of the nerves of the spine, which is called spinal stenosis.

There are many other causes for back pain including infections and malignancies, but these conditions are relatively rare and are not discussed in this section.

There are many causes of back pain and there are many different treatments for these different kinds of back pain. Some treatments, such as physical therapy and pain medications, can be used for many different causes of back pain. Some treatments, like nerve blocks or surgery, are used only for specific back pain problems.

Back pain is complicated and it can be difficult to tell what part of the anatomy the pain is coming from. Back pain can be caused by injury to or irritation of muscles, ligaments, back joints (the facet joints), the bones of the spine, the spinal nerves, and the discs. So, how do we know what to treat or more specifically, how do we find the pain generator of the back?

Finding the Pain Generator

Physicians can find the cause of your back or neck pain (the pain generator) in different ways. They can find the "pain generator" by asking appropriate questions (taking a history of your problem), examining your spine, arms or legs (the physical examination), using imaging studies such as x-ray, CT scanning or MRI that provide pictures of your back, or by performing diagnostic injections.

1) By history: The answers to these questions help your doctor focus in on the pain generator:

2) By examination

a. Your doctor may apply pressure to areas of your back or neck, shoulder or buttocks, trying to elicit points of tenderness.

b. Your doctor may ask you to move in certain ways that may bring on your pain or make your pain worse. For example, he or she may ask you to bend forward and backward and rotate your body. Your doctor is not trying to hurt you, but gathering information to help him or her make a more educated diagnosis of the cause of your pain.

c. A complete examination will include a neurologic examination of the lower extremities including deep tendon reflexes at the knees and ankles, a test of your sensations, and a test of your motor strength.

3) By X-rays, CT scans, or MRIs

a. X-rays are used to see the bones of the neck, thorax and low back. Your doctor can also see alignment of the spine and the state of the facet joints, whether normal or abnormal. An x-ray of the neck or back cannot tell us anything about the state of the discs or soft tissues of the spine.

b. CT scans result from special x-ray equipment that takes many different images from different angles. A computer then combines the images to show a cross section of the body area being examined. CT scans tell us little of soft tissues and a lot about the bones of the spine.

c. Magnetic resonance imaging or MRI uses a different type of technology to give us a picture of the bones and soft tissues. These imaging techniques are excellent for observing normal and abnormal soft tissues of the spine including the discs.

4) By electrodiagnosis

a. All muscles are innervated by spinal nerves. Because this innervation is electrical, certain tests including electromyograms and nerve conduction studies can determine if the electricity coming through these muscles is abnormal or normal.

5) By injection

a. Pain doctors who are anesthesiologists, neurologists, physiatrists, neurosurgeons, and orthopedic surgeons are trained to place needles anatomically on or near individual nerves, including the nerves leaving the spine. They can then inject a local pain reliever (anesthetic) near these nerves, making them numb, which can tell these doctors a lot about where the pain is coming from.

b. These diagnostic injections include spinal nerve root injections, facet joint injections, peripheral nerve injections, and more.

c. Challenge discograms are injections of x-ray dye into the intervertebral discs. Normal discs, when injected do not hurt, but may cause some discomfort that is not like the pain you regularly feel. When injected, an abnormal disc that is causing your back or neck pain will cause pain that mimics exactly the pain that you are feeling. We call this injected causing pain that mimics your pain, "concordant pain." Presumably, if there is concordant pain, then a diagnosis of pain coming from the disc, discogenic pain, is made.
 
 

Multiple Therapies, Multiple Choices: How to Choose?

There are many different therapies to treat back or neck pain, after the pain generator is found. Even if the pain generator is not found, there are therapies that can reduce your pain such as pain medications, exercise, or physical therapy.

Pain therapies are either non-invasive or invasive. Table 1 lists possible therapies by invasiveness. Included in this table are some of the complementary therapies that may help back pain.

Because there are many different treatment options – both invasive and non-invasive – physicians try to use therapies in a way that makes sense. In some people, non-invasive therapies work well. When non-invasive therapies work well, patients do not have to undergo more invasive treatments. Sometimes, non-invasive and invasive therapies are used together to complement each other. Also, some therapies are used only for very specific pain generators. For example, facet joint injections and facet joint radiofrequency thermocoagulation (destroying the little nerves that innervate the joint) only help with facet joint pain and will not help the pain of sprain or strain or even discogenic pain.

Table 1: Therapies for back pain

Pain Treatment Continuum

Remember the goals of treatment are to reduce pain and improve both emotional and physical functioning in a practical and cost-effective way. Figure 1 is an example of an approach to trying therapies in a logical way, trying therapies that are least invasive to therapies that are more invasive. We call this a Pain Treatment Continuum.

FIGURE 1: Therapies to reduce pain are either pharmacologic (pain medications), functional restorative (physical and occupational therapies), cognitive behavioral (helping one cope with the emotional and behavioral aspects of pain), or a combination of the two.