Understanding Low Back Pain
Thomas J. McGivney, MD

Low back pain is one of the most common conditions for which patients will seek care from a physician. It is estimated that 65-80% of all US citizens will suffer from at least one episode of low back pain during their lifetime. In fact, 8% of all doctor visits and over 12% of prescribed medications are attributable to low back pain. The estimated cost of treatment for these problems is staggering. Approximately 13 billion dollars are spent in the US annually to treat low back pain and over 40% of all lost work days are attributable to low back problems. In 1997 alone, for example, over 300,000 patients underwent surgery for treatment of the lower back, and that number represents only a small fraction of all the patients who had a variety of low back problems.

The lower back is made up of a wide variety of structures and tissues. Muscles, ligaments, tendons, bones, joints, discs and nerves comprise the structures that make up the low back. A variety of conditions—congenital, developmental, degenerative, traumatic and a host of others—can result in any one of a number of disorders that can produce low back pain syndromes.

The first key in the assessment of a patient with low back pain is an accurate history to determine where the pain is located, how and when it began, whether it has been recurrent, what factors aggravate or alleviate it and whether there are associated symptoms such as numbness or tingling, weakness or abnormalities of bowel or bladder function. Physical examination can disclose deformities of the spine, areas of tenderness, limitations of motion, weakness of muscles, reflex deficits, areas of sensation loss and other abnormalities. X-rays may be taken to assess the alignment of the bones, the presence of arthritic changes, the possibility of fracture but they do not show the “soft” tissues, such as the discs and nerves. To “see” them in detail requires other studies such as MRIs or CT scans which can be done if needed. Special studies of nerve function (EMGs or NCVs) are sometimes ordered to try to localize the site of nerve compression or other abnormality. In some cases laboratory tests may be necessary to evaluate for the possibility of infections or other unusual causes of low back pain. The most common causes of low back pain are said to be myofascial or mechanical—related to the muscles, tendons and ligaments of the back. Muscle strains and pulled ligaments are usually caused by occupational or recreational activities and result from abnormal or repetitive movement, excessive or improper lifting, minor falls or other injuries. In such cases, fortunately, resolution of the problem can usually be achieved with rest, medication and short courses of massage therapy, physical therapy or chiropractic therapy.

Arthritis of the spine usually develops in the 6th or 7th decade of life and is ordinarily simply due to “wear and tear” or the simple process of aging. Its onset is often associated with the development of arthritic symptoms in other areas of the body. At its mildest it may be manifest as low back stiffness when getting out of bed in the morning or a low backache after working, lifting or golfing, for instance. It can be a disabling pain that increases the longer you are on your feet and it makes you cease activity to go lie down. At this stage arthritis may well respond to rest, medications, therapy and, in some cases, surgery to alleviate the pressure on the nerve and/or to fuse bones of the spine together to prevent or treat instability.

A disc is a cushion or shock absorber located between the bones of the spine. Think of a disc as having two parts—like a golf ball with a liquid center and an outer cover, or a jelly bismark with a semi-solid, semi-liquid center and an outer crust. The disc has such a liquid center (the nucleus) and an outer layer (the annulus). As part of the aging process the liquid center has a tendency to dry out a bit so that the disc no longer cushions as well as it once did. When the disc dries out it has a tendency to get flatter (that’s one of the reasons we usually get shorter as we age) and then, like a marshmallow squeezed between two fingers, it gets fatter! That’s a “bulging” disc. When that causes symptoms it is called degenerative disc disease and it’s simply another form of arthritis, the treatment options for which are noted above.

In some cases the center portion of the disc, which is under a lot of pressure, can be pushed out through the outer layer. That’s known as a slipped disc, or a ruptured disc or a herniated disc. The part of the central disc material that is pushed out will often put pressure on a nerve, again resulting in leg pain, numbness or tingling, or weakness. The nerve is called the sciatic nerve so the pain is often referred to as “sciatica”.

Most of the time with conservative treatment of rest, medications, therapy or cortisone injections the herniated disc material will dry up and shrink to the point that it no longer puts pressure on the nerve and the symptoms will disappear. If the herniation is large and puts a lot of pressure on the nerve or if leg signs and symptoms persist despite a period of conservative treatment, then surgery to remove the herniated piece it the disc is needed—but that occurs in only about 20% of patients with herniated discs.

Fractures of the bones in the spine (the vertebral bodies) can certainly occur as the result of significant trauma such as falls, auto accidents and the like. And some of those injuries, as you may know, can even result in paralysis. Commonly, however, the bones of the spine can fracture with little or no known injury because they have been weakened, usually by osteoporosis. Such conditions, known as compression fractures, rarely cause any kind of nerve injury or paralysis and usually heal without any treatment other than rest, medication and, in some cases, a temporary brace. A word to the wise—prevention of osteoporosis can go a long way toward reducing the risk of such fractures. Those at risk for osteoporosis (for example, post-menopausal women) should discuss prevention and treatment of osteoporosis with their primary care physician and should pursue appropriate tests and treatment.

There are countless other, less frequent causes of low back pain. Because low back pain is such a common occurrence with such enormous costs to both individuals and to society as a whole, there is constant intensive ongoing research on how to best prevent, diagnoses and treat patents with these varied conditions. We at Castle Orthopaedics and Sports Medicine are committed to staying abreast of all the important developments for the betterment of your health.

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