Low-Back Pain - Causes and Treatment

In a busy primary clinical practice, at least one patient a day comes in with a backache. It is one of the most common human ailments. Most of the problems are with the lower back; and no wonder. The lower back is the "axle" on which most of the other muscle movements base their action. By going through an approach which looks at the history of the pain and the mechanics of the lower back, the doctor can hopefully come up with a successful plan of treatment.

The history is very important, i.e., when did the pain first appear? Is it something which occurs frequently, or is this the first time? What is the nature of the pain: Sharp, dull, intermittent or constant? Does it "radiate" somewhere or does it remain in one area? What were the activities prior to the pain? Maybe you were moving railroad ties around your garden, or continuously leaning back to paint a ceiling. Maybe you've been sleeping on a roll-away bed while guests are visiting and it has a six inch mattress with a metal bar halfway across it. Do you have fever or blood in your urine (kidney stone)? By this process, your doctor tries to "sift out" the exact nature and specific history of your back pain.

The second step is to look at the back. Starting with the skin, is there an isolated rash that might be shingles? Is there an infected cyst or an area of skin infection, such as one surrounding a tick bite? Now look at the posture. Is the back too straight, as from muscle spasm? Does it curve to the left or right (scoliosis), and is this a permanent finding or is it due to muscle spasm? Does the back curve too far toward the front (lordosis), maybe due to a prominent "pot belly?" As part of this process your doctor might make other observations. Do walking and standing make the pain worse, and is it primarily movement of one leg that seems to cause the problem? When one sits in a chair, does he slouch with poor posture, or sit too straight from muscle spasm?

The next thing I do in evaluating back is imagine that I have "x-ray vision", and using the anatomic map I have in mind, go down through the back one layer at a time looking for something wrong. The outermost muscle of the back is the latissimus dorsi which goes all the way from below the "wing" bones (scapulae) to the crests of the hip bones. Weight lifters like to build these up for aesthetic purposes. It has a very broad ligament which stretches over and attaches to the entire lower back. It has a lot of cutaneous nerves which come through the muscle and can be pinched by muscle spasm. The very broad ligament is like any other ligament of the body: it can be stretched or torn causing pain and swelling. Under that is a very large fascia which is like a ligament, and is called the lumbo-dorsal fascia. Deeper muscles of the sides of the back attach to this, and the whole structure is subject to often multiple varieties of strains and tears. Finally, in the third layer are the deep muscles of the back which run parallel to and attach to the spine. They have ligamentous attachments to the lower back and are subject to strains and tears.

Underneath these layers of the back muscles are the actual spine bones. They are very large and sturdy, except perhaps in the case of an elderly person with osteoporosis. There are five lumbar vertebrae, five sacral vertebrae (which are fused), and four coccyx vertebrae. They are held together with ligaments on the front, sides, and back. There are cushions between the lumbar vertebrae called discs which have gelatinous centers and fibrous outer sheaths. Sometimes the gelatinous center ruptures out through the fibrous sheet and this is commonly referred to as a "ruptured disc." The gelatinous material can impinge on a spinal nerve coming out of the spinal cord, and cause pain down the back of the leg. This is called "sciatica." Sometimes the disc can rupture inward and actually push on the spinal cord. This may cause bowel and bladder problems and other neurological symptoms.

The doctor examines you continually looking for clues. Is the pain localized to one of the muscles of the back or to its ligamentous attachments, or does it seem to be a deeper process? In looking for a deeper process, the examination often focuses on the legs. The doctor might look to see if there is muscle atrophy due to a nerve injury up around the spine. Are there precisely located areas where the skin is numb or has decreased sensitivity? Are the reflexes brisk and equal at the knees and ankles (looking for the same nerve injury indications)? Is there weakness in pushing down with the great toe (a sign of L5-S1 nerve impingement)?

Now it's time to consider other potential causes of back pain. A kidney infection or kidney stone can cause back pain over the areas of the kidneys. Sometimes a dysfunctional gallbladder can cause back pain. As people grow older, particularly if they smoke, they can get aneurysms of the abdominal aorta, which the doctor might pick up by x-ray or listening to the mid-abdomen. The next step is to decide what tests might be needed to diagnose the back pain. X-rays cannot visualize the muscles and ligaments, so your doctor may decide how to proceed. However, if he or she suspects arthritis, a narrowed disc, a kidney stone or aortic problem, an x-ray may be correct. If the doctor thought it was your kidneys, they would order a urinalysis. If they think it is a deep process involving a disc or the spinal cord, the doctor would order either a CT or an MRI.

Let's talk about treatment. First of all, he or she might put you on a "no lifting" physical profile, with no prolonged standing or sitting. If you have a muscle strain, they might prescribe an anti-spasmodic medicine and an anti-inflammatory medicine like Ibuprofen. They might inject a localized strain with a local anesthetic, and perhaps a cortisone-like medicine. If it just happened, the doctor might tell you to apply ice packs, and gradually change to warm soaking baths after 5-7 days. If they find a deeper problem like a ruptured disc, he or she would probably refer you to an orthopedist or neurosurgical specialist, to a kidney specialist for a stone, or to a vascular surgeon for an aneurysm.

By far, most of the day-to-day back problems are tears and strains of the back muscles and ligaments. By knowing the anatomy and the mechanisms of back pain, your primary physician can successfully treat and resolve the majority of back pain problems.