According to many studies, up to 85% of people in the United States will have an episode with low back pain. In fact, low back pain is second only to upper respiratory infections (the common cold) as a reason for missed work time! That’s right, more people miss work due to low back pain than any sickness under the sun beside the common cold, pretty staggering. So why do so many of us have low back pain? The answer can be complicated, so instead, much of our medical community has come up with a scapegoat who you probably have heard about. The vaunted “lumbar (low back) disc herniation” or “lumbar disc bulge”. So what is a disc herniation and how is it different from a disc bulge?
To understand a disc injury, first, you have to understand a disc. Very simply put, a disc is a shock absorber for your spine. Instead of relying on bones to buffer themselves from injury when we do high impact activities like walking, jumping, running, and lifting weights, the human body has an intricate system of shock absorbers (discs) between each spinal bone. A disc is not much different than a jelly doughnut in regards to its anatomy and physiology. The outside of a disc (annulus) is a pliable but hard series of cartilage rings while the inside of the disc (nucleus) is a viscous fluid made mostly of water. Think of the cartilage as the doughnut and the fluid as the jelly in your jelly doughnut. In healthy discs, when we bend forward, the fluid goes backward, and when we bend backward, the fluid moves forward, and so on and so forth.
A herniated disc is what happens when the pressure on the nucleus (jelly) becomes so great that it actually pushes through the annulus (doughnut). In most cases, perhaps as high as 90% of the time, this type of injury will happen in the back of the disc on either the left or right side (dangerously close to where the nerves come out of the spinal cord). A disc bulge as seen in the picture attached to this article as well as what happens when pressure on the nucleus of the disc becomes great enough that it tries to force its way out of the annulus unsuccessfully. Basically, it forces a weak spot to develop in the outside cartilage but never gets all the way through. Both herniated and bulging discs can be seen clearly on MRI (Magnetic Resonance Imaging). They cannot, however, be decisively diagnosed on an x-ray. An x-ray or plain film radiograph is used as a precursor to the MRI and can suggest the presence of a herniation or bulge without definitive confirmation.
So now you know what disc herniations and bulges are. Maybe you have one. Your medical doctor, orthopedist, chiropractor, or physical therapist has told you or someone you know, “you have herniated discs in your back and this is why you have back pain.” Okay, problem solved, you know what has caused your symptoms, and there isn’t much you can do about it if you don’t want surgery according to your doctor of choice. Well, what if I told you that according to the most recent research, the presence of disc herniations and disc bulges in MRI are not at all conclusive as being causative for low back pain? I promise you, I’m not crazy. I brought some of my heavy hitters with me to prove my point.
In a groundbreaking study performed by the New England Journal of Medicine, 98 asymptomatic (pain-free) people were given MRI examinations to determine the presence or absence of lumbar sic herniations. The findings were surprising. Of the 98 individuals examined only 36% (about 36 people) had what doctors consider “normal discs at all levels”. Over 52% had at least one disc bulge while 27% had at least one disc herniation! The conclusion of the study… “The discovery by MRI of protrusions (disc herniation) in people with low back pain may frequently be coincidental.” I’m sorry, what? That can’t be right.
In a follow-up study, the Cleveland Clinic performed the same clinical trials over and over again imaging hundreds of subjects. Their findings… “25% of all asymptomatic people who climb into an MRI machine will have a herniated disc… As many as 60% of healthy adults with no back pain have degenerative changes in their spines”. What! Seriously? Yes. The Cleveland Clinic study was even published in the New York Times back in 2008!
Let’s take this one step further because those results can’t be right. Dr. Modic of the Cleveland Clinic wanted to examine symptomatic patients. 250 patients to be exact, all of whom had back pain or pain shooting down their leg which can commonly be caused by herniated lumbar discs. The findings were that 60% of the subjects had herniated discs. “Ah ha,” you say, the number goes up in people with pain. Yea, it does. But check this out. Six weeks after the initial scan, another MRI was performed to determine the relationship between the patient’s symptom changes and the imaging findings. The results, in 13% of the subjects the herniated disc had actually grown larger and in 15% the herniation had disappeared altogether. The interesting part is that there was no, zero correlation between the presence of the disc injury on the second scan and patient symptoms. Some patients with no disc injury on the scan had gotten worse, and some with worse disc injuries on the scan had improved. How do we explain this?!
It’s really simple. The disc is not likely the primary cause of the patient’s discomfort. It is simply a radiological finding that doctors should put in their notes while they keep looking for what your real problem is. Don’t get me wrong, there are instances where disc injuries can be so bad that surgery is needed to alleviate them, and in those cases, surgery should be performed. However, my point is that disc injuries are typically unreliable as pain generators and should not be the scapegoat for your low back pain. Don’t worry, I’m not going to leave you hanging, I’ll tell you what the problem is.
Compensation. Your body was meant to work a certain way. Every muscle, every joint, every nerve, and every cell has a distinct, unique purpose. When something breaks down, something else has to pick up the slack. My favorite analogy for disc herniation is a crew team. If there are five people in a boat rowing for a common cause, there is a definite speed that they can achieve for a definite distance. If we take one of the crew members out of the boat (injure a disc or other tissue), the other four team members have to work 25% harder each to replace the fifth team member. Eventually, their pace slows, the form breaks, and the boat stops being effective. This happens in your body as well.
If you injure a disc in your low back, which as you now know is extremely common, your body becomes littered with compensations. Other muscles and structures begin picking up the slack for the guy who abandoned ship only to break down eventually. And what happens when your body breaks down? Pain.
Fortunately, your body is extremely efficient at replacing losses by compensating for them. Unfortunately, this can be a painful, and potentially debilitating. You might be suffering from it right now, you definitely know someone who is. So you have two choices. Deal with it until the pain (not the compensation, but the pain) goes away, or try and get it fixed. Either way, now you know, and knowing, as they say, is half the battle.