Conquer Back and Neck Pain - Walk It Off! (3 page)

As you walk around during the day, the weight of your body normally squeezes some of the water out of your discs and you get shorter. During a good night’s sleep, normal discs suck up the water again and you become taller by morning. This is important for the health of your disc, but it’s a big problem for astronauts. In the weightless environment of space, spinal discs swell so much that they can actually fracture the attached vertebrae and cause back pain. Back on earth the same thing can happen to you if you are forced to spend too much time in bed. More will be said about this in
Chapter 11
.

So what does all of this mean with respect to back pain? A number of genes have been identified that control the way the cells make and maintain the sponge in our discs. When we are missing a few of these genes, the cells are programmed to make a sponge that does not hold the water tightly enough to allow the disc to function properly. Not only does the disc cushion poorly, but food cannot get into the cells in the disc and waste cannot get out. The cells get sick and eventually die and the disc begins to literally fall apart, or degenerate. When this happens the disc cannot bear weight properly and begins to narrow.

Picture the situation where you are driving down the street and you notice that one of the tires on the car in front of you is half flat. You are most likely compelled to drive up alongside of the car, blow your horn to get the driver’s attention, lower the window of your car, and warn the driver of the condition of their tire. Why? Because you know that there is not enough air in the tire to distribute the weight of the car properly and you are afraid that a half-flat tire may blow out and cause an accident.

The same thing happens when a disc degenerates. The loss of water in the center of the degenerated disc causes it to deflate and lose its ability to cushion. Abnormal weight is placed on the tough side wall of the disc (annulus fibrosus) and it breaks down. Initially, tears in the side wall of the disc are not felt because there are no nerves in the disc itself. But when the tears reach the nerve endings in the surrounding tissues, back pain may occur. When tears go completely through the rim of the disc, the spongy center of the disc may herniate completely through the tear in the side wall and compress the adjacent nerve to produce leg or arm pain.

Sometimes the center spongy part of the disc becomes so degenerated and dried out that it cannot squeeze through the tears in the rim of the disc to cause back and extremity pain. This is an important concept to understand, so I’ll explain in the next few paragraphs how disc degeneration is detected and how we know it sometimes causes pain and at other times does not.

Since the development of MRI scans (see how MRI works on page 52) we can clearly see the extent of spinal disc degeneration without the need for any injections or x-ray exposure. MRI scans have been used in population studies and have shown that there is some degree of disc degeneration present in almost every adult, whether they have a history of back pain or not.

Some medical scientists say that disc degeneration is not the cause of back pain. They draw this conclusion because several classic MRI studies have revealed disc degeneration in people who had never experienced back pain. Yes, there really are a fortunate few! The incidence of disc degeneration detected on the MRI scans of these fortunate individuals is not much different from that in a group of people who have suffered from back pain. So, some medical experts have used these studies to debunk the disc as the source of back pain. I and other spinal experts disagree with them; we interpret the results of these studies to mean that disc degeneration may or may not result in pain, and that people with disc degeneration but no back pain at the time of the MRI scan are likely to develop pain related to it in the future.

In other studies using discography (injection of x-ray dye into the disc to determine the degree of degeneration and to stimulate back pain), it has been shown that some discs become pain stimulators during the course of degenerating and some do not. Performing discography on the same disc at different times has also shown that some discs may be painful at one stage of degeneration but not in a later stage of degeneration. This concept is important in understanding how it is possible to obtain relief from chronic back pain (
Chapter 8
).

There are four ways that disc degeneration can cause back and/or extremity pain:

• through pressure on a spinal nerve from a disc herniation or from constriction of the spinal canal (neurogenic pain)
  

• through susceptibility to sprains and strains (mechanical pain)
  

• through leakage of painful breakdown products of the disc itself (discogenic pain)
  

• when disc degeneration results in deformity of the spine such as curvature (scoliosis), it may result in muscle-fatigue pain
  

When disc material actually herniates into the spinal canal it can compress and irritate the spinal nerves, which can result in pain in the extremities. Shakespeare, in the play
Timon of Athens
, 1564, described “thou cold sciatica crippled our senators that their limbs may halt as lamely as their manners.” Sciatica is a pain that travels down the back of the legs along the course of the sciatic nerve and is usually caused by a disc herniation in the low back (lumbar spine). Disc herniations in the neck (cervical spine) can cause pain in the arms; disc herniations in the spine behind the chest (thoracic spine) can cause pain in the chest and abdomen.

The late stages of disc degeneration result in deflation of the disc and bulging of the outer rim. When this occurs, narrowing of the spinal canal and nerve channels may result. This is called spinal stenosis. If the narrowing of the spinal canal results in compression of the spinal nerves, back and extremity pain may result. My aunt’s demise was caused by spinal stenosis in her neck, which in addition to pain resulted in compression of her spinal cord and paralysis. I will devote an entire chapter to the subject of spinal stenosis since it is the most common cause of neck, back, and extremity pain as we get older — yet most people have never even heard of it!

As discs become progressively degenerated, they may become unstable and susceptible to repeated painful sprains from the stress of normal activity. This a common cause of chronic mechanical lower-back pain. I will discuss the consequences of the late stages of disc degeneration, how to prevent them, and how to get relief from them in several chapters of this book.

In the final stages of disc degeneration the discs begin to stiffen up to the point that they become functionally fused together by bone spurs, called osteophytes, on the margins of the vertebrae. This is a normal healing process by the body in response to repeated small sprains of the disc when it is not bearing weight properly during the early stages of disc degeneration. The bone spurs that form at the attachment of the disc to the vertebral bodies act to stabilize the disc. However, bone spurs from disc degeneration may contribute to narrowing of the spinal nerve channels and cause nerve pain. More will be said about this in
Chapter 6
on spinal stenosis.

Disc degeneration may result in slippage of the spine (spondylolisthesis), curvature of the spine (scoliosis), and/or a bent spine (kyphosis). Any one or a combination of these deformities can throw the spine off balance. The normal reflexes in your body will try to keep your head centered over your pelvis. When the spine is out of balance, these reflexes make the muscles continuously work to correct the deformity. As a result, the muscles fatigue and become painful.

During the course of disc degeneration, the breakdown products of the tissues may themselves become irritants and leak through cracks in the sidewall of the disc to cause inflammation in the surrounding nerve endings. The pain that results can come and go without warning or apparent cause. Pain resulting from irritating breakdown products of a degenerated disc is difficult to diagnose and to treat. It will be discussed throughout this book, especially in the chapter on chronic back pain.

Through an understanding that disc degeneration is genetic, ubiquitous in humans, and responsible for the majority of painful conditions of the spine and extremities, I developed a strategy for diagnosis, treatment, and prevention of spine pain. The strategy will be presented in the following chapters. Referring back to this chapter as needed, I will give you a better understanding of how to obtain relief from back pain and how to keep your back pain from recurring.

The next chapter will describe the seven types of neck and back pain and includes a questionnaire to help you determine the type(s) of pain that you have. You can use this questionnaire as a guide to various types of spine pain in the remaining chapters.

The seven types of neck and back pain are:

1. Nerve root pain
   from compression and irritation of a spinal nerve by a herniated spinal disc
   

2. Neurogenic pain
   caused by loss of oxygen to the spinal nerves by constriction of the spinal canal (spinal stenosis) and/or smoking
   

3. Mechanical pain
   , caused by an unstable spine from an injury or defect such as spondylolisthesis (slippage of the spine)
   

4. Chemical or discogenic pain
   from breakdown products of a degenerated disc
   

5. Muscle fatigue pain
   from an out-of-balance deformity such as curvature or slippage of the spine
   

6. Inflammatory pain
   such as from arthritis or infection of the spine
   

7. Central pain
   resulting from a low threshold to pain, secondary to depression and/or narcotic-induced depletion of endorphins
   

Neck and back pain conditions are usually the result of some combination of these types acting at the same time. In the first phases of disc degeneration, mechanical pain from a loose disc may predominate. In later stages of disc degeneration, the primary discomfort may be chemical pain from irritating breakdown products of the disc. A herniated disc may cause nerve root pain by stretching and compressing an adjacent spinal nerve, whereas a collapsed bulging disc may cause constriction of the spinal nerve channels (spinal stenosis), resulting in neurogenic pain. Inflammatory pain may come from a disc-space infection or from one of several forms of inflammatory arthritis that affect the disc, such as rheumatoid arthritis and ankylosing spondylitis. Pain that is experienced as the result of faulty central (brain) pain modulating systems is usually secondary to depression and/or depletion of our body’s own natural pain killers – our endorphins – by narcotics or muscle relaxants.

It is important to know what type of neck and back pain you are suffering from, because the treatment and prevention of recurrence will differ depending on the type. Treatment for one type of pain may make another type of pain worse: painkillers for nerve pain may make central pain worse, and disc excision to treat neurogenic pain may cause the disc to collapse further and exacerbate spinal stenosis and neurogenic pain.

How do you know what type of neck and/or back pain is causing you to suffer? The following questionnaire is made up of statements or questions that are grouped into the seven types of pain. If you answer most of the questions yes in one group you are probably suffering from that type of pain. However, it is also possible that you are suffering from more than one type of pain at the same time. Let us begin the quiz.

If you answer most of these questions with a yes, then you most likely are suffering from nerve root pain from a herniated disc:

• I have pain from my low back down the back of my leg, down the front of my leg, or from my neck into my arm.	Yes No
• The pain in my leg or arm is associated with numbness, tingling, pins and needles, or other bothersome sensations.	Yes No
• I have difficulty sleeping because of the pain.	Yes No
• The pain in my leg causes me to limp.	Yes No
• The pain makes my knee give out or makes my ankle weak.	Yes No
• The pain in my arm causes me to lose my grip on things.	Yes No
• The pain in my leg is worse when I lean forward while I am standing.	Yes No