A vast majority of the time, when someone comes to me with low back pain, they tell me that they have been diagnosed with a “slipped” or herniated disc which must be causing their pain. Well, not necessarily.

First, let’s talk about disc pathology. The vertebrae surround the spinal cord, and between the vertebrae are sponge-like discs. From out of the spinal cord come the nerves which supply your extremities and your organs. Discs often develop bulges which are kind of like a bleb on the side of a tire. When the bulge puts pressure on a nerve, the irritation causes you to feel symptoms in any area supplied by that nerve.

Nerves are relatively small while the circumference of a disc is comparatively large. Not every bulge in a disc will put pressure on a nerve. It is likely that you have a disc bulge or two that cause you no trouble whatsoever. In fact, about 30 percent of you are walking around with disc bulges of various sizes. Of those of you with disc bulges, only a few will actually have symptoms.

The symptoms of disc pathology are fairly specific. The hallmark sign of disc pathology is referred pain (pain that is felt far away from the actual site of the injury). Because we are talking about low back pain today, the disc problem in your lower back probably causes leg symptoms. You probably notice that your leg symptoms are better when you are up and moving around. Sitting is nearly intolerable, though, since it significantly increases your symptoms.

The leg symptoms themselves are specific to the nerve which is being compressed by the disc. Depending on the nerve, you will describe pain through a predictable portion of your leg. You will not talk about pain in both legs (though you may have some bit of pain in the both butt cheeks). The symptoms from disc pathology do not create a “stocking” effect covering your whole leg. Since the nerves come out opposite sides of the spinal cord, a disc bulge will likely only put pressure on one side or the other causing pain in only one leg. If you have symptoms in both legs, we can almost rule out the likelihood of a disc being to blame.

There are a wide variety of problems that cause back and leg pain; disc pathology is only one on the long list. To successfully treat your symptoms, it is important to have an accurate diagnosis. As I said earlier, you may have a disc bulge or two as many folks do. The question then becomes whether the disc bulge is actually causing your symptoms or whether the disc bulge has simply been discovered incidentally in the course of trying to learn what is causing your pain.

Unfortunately, once a disc bulge has been discovered on your MRI, a kind of tunnel vision develops. A patient comes in complaining of back and leg symptoms. An MRI is ordered and a disc bulge is discovered. At this point, we sometimes quit listening to the patient and presume it is the disc bulge causing the pain. If you are telling me that your pain is in your back and right butt cheek, never goes below your knee, is better when you are sitting and extremely painful when you stand or walk more than 20 minutes, then the disc bulge that shows on your MRI on the left at L5-S1 (which would cause symptoms in your left lower leg and foot) cannot possibly be causing your symptoms.

It becomes an imperative to have an accurate diagnosis before you undergo surgery. Imagine the same patient above having a laminectomy to repair the “offending” disc bulge and waking up not only to the same symptoms he had prior to surgery, but now there are additional surgical symptoms. This is how the horror stories we are all familiar with about the “evils” of back surgery get started.

The causes of back and leg pain vary considerably and so do the available treatments for that pain. Treatment for a lumbar disc herniation is not likely to do you much good if you actually have a muscle strain, injury to a ligament or instability in your low back caused by muscle imbalance.

Surgery can only treat problems with the anatomy that are actually causing you pain. When the pain you are having is caused by a disc bulge and you have tried other treatments available without success, surgery might well be the answer. More often, though, pain in your back and leg is caused by something else. More often than any of us like to admit, the exact source of your pain cannot be clearly identified. These are the folks who wind up having a tragic series of back surgeries in a well-intentioned, but unsuccessful effort to relieve their pain.

As a physical therapist, when you come to me for back and leg pain, I am more concerned with identifying which treatment will work best for you than I am with identifying the specific tissue that is causing your pain. Are you a patient who will benefit from exercises to improve the strength and stability of your back? Will you respond better to traction? Or do you need mobilization to restore normal movement to stiff areas of your back? Unfortunately, there is no cookbook that will give us the “silver bullet” to cure everyone’s pain. Working together, though, talking about your symptoms and your response to treatment, we can help find a non-surgical solution to most causes of back and leg pain.