After talking with patients for just a few minutes, most orthopedic surgeons can recognize the classic symptoms associated with bulging or herniated discs. A not uncommon progression of pain goes something like this:
“I hurt my back and had terrible back pain, but after a few days the pain shifted to my buttocks, where it got worse than the back pain. Now, a few days later, I have mainly leg pain, and am feeling some weakness in my [right or left] leg.”
Does that sound familiar to you? Most patients describe the pain associated with a bulging or herniated disc in a similar way. Once you understand what’s happening biologically, this progression makes perfect sense. In this article, I’ll explain what’s causing the pain at each stage, and the most common bulging and/or herniated disc treatment options.
How does a bulging and/or herniated disc happen?
Discs are the material between pairs of vertebrae in your spine. They are designed to carry the weight of your body and also create space between the vertebrae for nerves.
The outer part of the disc is called the annulus. It has a tough exterior made of annular fibers that interlink or interweave at roughly 45 degrees (like a radial tire) that help control rotation and bending of the spine. The middle part of the disc, called the nucleus, withstands the axial forces of the spine. When the nucleus is compressed it creates a hoop stress, exerting a circular force all around the annulus. If the force is strong enough, the annulus will break. (Think of it like pressing on a water balloon: When you push, the outer material tenses up due to force and will break if you push hard enough.)
Sometimes that breakage occurs as part of the natural degeneration caused by aging. Like your skin and your hair, your discs are also made of collagen, which means that naturally, over time, they dry out and crack. When the outer layer of a disc gets weak, sometimes the inner layers push out and bulge the outer rim of the disc. Or, breakage could happen as the result of mechanical pressures—like bending or lifting improperly.
What makes a bulging disc painful?
In its early stage, when a disc is still bulging, no breakage has yet occurred. All the disc material is still contained within the annulus but is pushing out or bulging against the outer rim of the disc. Bulging discs are common; in fact, many people have them without realizing it. (A study from the 1990s showed that more than 50 percent of people randomly chosen for MRI scans had one or more bulging discs without back pain.)
Sometimes the pushing force creates abnormal pressure and the bulge increases significantly, to the point where the condition is considered a protrusion.
If the outer layer weakens enough, the nucleus of the disc may come out, or herniate, into the bulge. (To put it in perspective, bulging is to a herniated disc like a cold is to pneumonia.) As the protrusion goes to a herniation there’s usually some type of permanent change in the disc—think about bending a piece of plastic hard enough so that it permanently changes shape.
The outer part of the disc has pain fibers in it, so if you do get an annular tear, it hurts. Also, tearing prevents the disc from functioning normally, which also creates pain in the low back.
Once the disc pushes all the way through the annulus, very often the back pain lessens because there’s no longer pressure on the disc. But once the disc moves outside its normal anatomical position, it compresses nearby nerves or neural elements, causing pain in the leg. Additionally, the inner part of the disc is irritating to nearby nerves because of its chemical makeup—it is sponge-like and largely made up of acidic fluid. The nerve reddens and swells, causing it to take up more space and be compressed even more.
Finally, sometimes a disc that has broken through a torn annulus may completely separate and become a free-floating fragment in your spinal canal. This is referred to as a sequestered disc herniation. It doesn’t typically move much—maybe a centimeter—but it’s just as irritating to your nerves as a herniated disc. Once it sequesters the pressure comes off the annulus, dramatically decreasing the back pain, but continuing the leg pain, which may also include tingling, numbness, and even weakness.
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What is the appropriate bulging/herniated disc treatment?
The different terminology used to describe the displacement of a disc is merely a way of helping the medical community—radiologists, therapists, and spine surgeons—more precisely communicate a patient’s condition. The name isn’t what’s important—what matters is the degree of damage to the internal architecture of the spine and what problems the condition is likely to cause. Treatment decisions are best made by evaluating the MRI imaging, the severity of the condition, and the patient’s medical history combined.
Most spine surgeons think of bulging discs as benign, and they will not treat them at all if there is no pain. Usually, it isn’t until a significant, painful protrusion or an annular tear happens that doctors recommend trying one or more conservative treatments. Conservative treatments are meant to help manage the pain in hopes that the body will heal itself, which has been shown to happen in a large percentage of disc herniation cases. If one type of conservative treatment isn’t having any impact after six weeks, give another one a try. In the case of a herniated disc causing nerve inflammation, steroids either by mouth or by injection may help relieve the pain of the inflammatory process.
Even if the condition is still present, there’s usually no need for further treatment if the pain disappears. By six weeks, most people will be on their way to getting better. Four to six months is enough time to know whether the body will heal itself or not. Surgical decisions are made based on severity of pain and motor weakness.
In cases of sequestered discs, studies have shown that some patients recover on their own. There are many theories on how this happens, but some researchers believe that the inflammatory process is the body’s way of breaking down the disc. All we know for certain is that follow-up MRI scans in past studies have shown that, in some cases, the offending discs are much smaller or completely gone a year or so after the original MRI was taken.
Not all herniated discs heal themselves. Some conditions may create a structural problem that causes continued irritation, which means other bulging/herniated disc treatment options will need to be discussed. For more information on bulging and herniated discs, read our articles on recurrent herniated disc treatment options and how to heal a bulging disc naturally.