Degenerated Discs and Back Pain

Why “discogenic pain” is a Non-structural Diagnosis

The problem with calling this a structural diagnosis is that it is not humanly possible to tell which disc is the painful disc at a specific point in time. It is a reasonable supposition that if a person ruptures and L4-5 disc, that the preceding episodes of axial low back pain were probably from that disc. However, during that period of episodic low back pain, we don’t have the tools to accurately figure it out.

There are just two diagnostic tests that give us some insight as to whether a given disc is the source of your pain. That is the MRI scan and the discogram. Neither are accurate enough to base major surgical decisions.

I will repeat this a hundred times if needed. There is little, if any, correlation between the presence of degenerated discs and low back pain. This has been shown with X-rays, CT scans, and best with MRI scans. There is a lot that we don’t know about the cause of low back pain. But this is one fact that has been consistently documented. If you take volunteers who have never experienced low back pain, and perform and MRI scans, about half will have some disc degeneration by the age of 50. By the time an asymptomatic person is 65 years old, the incidence of disc degeneration is around 100%.

MRI Diagnosis

All an MRI scan will show you in regards to degeneration is that the disc has less water content than when you were younger. That implies that there is less motion in your lower back but does not indicate that these “degenerated discs” are the source of your low back pain.

There a many surgeons who will show you an x-ray that shows severe degeneration of your spine. The disc has almost completely disappeared. The implication is that with the degeneration being this severe that this must be the source of your pain. There are many fusions performed for this problem. To my way of thinking, the disc that has completely collapsed is the least likely source of pain. I am a deformity surgeon. I often perform surgery through the abdomen to “loosen” up the spine so I can then straighten it up. These collapsed discs do not move. If there is so little movement, how can it be the most likely source of pain? I did spend the first seven years of my practice diligently performing fusions based on discograms. The discs that had a fairly normal height and were partially torn seemed to have a higher chance of being painful with a disc injection than the completely collapsed disc.

There is a study published in the 1950′s, which looked at the incidence of low back pain after a simple disc excision. It was interesting in that the patients with the least back pain had more arthritis on their x-ray at that level and less motion on flexion/extension x-rays.

Every clinic day I evaluate patients for sciatica and other different types of leg pains. Many of them have severe degeneration of their spine at multiple levels. Although their leg pain can be severe, they often have no low back pain. Conversely, I will frequently see patients with severe back pain and a completely normal MRI.

I recently saw an very active middle-aged female with extreme pain down the side of her left leg every time she stood up or walked. She had no pain with sitting or lying down. She was also an avid cyclist, runner, and worked out at the gym regularly. She had narrowing around her fifth lumbar nerve root as it exited out of the side of her spine. Every time she stood up, the fifth nerve was tightly pinched. Her spine was one of the worst looking spines I have ever seen in any person of any age. Every disc was completely collapsed and each vertebrae was bone against bone. There was also a moderate amount of curvature. She had absolutely no back pain. She had never had significant back pain. I performed a one level fusion at L5-S1, which relieved the pressure on the nerve. The fusion prevented the opening around her 5th nerve from collapsing when she stood up. Her leg pain is gone and she is back to full activities.

This example is extreme only in the severity of the degeneration of the discs. I see patients routinely who present with severe degeneration of their spines and have only leg symptoms.

Degeneration of the spine associated with low back pain cannot be considered a structural lesion. Degeneration of the discs is a normal process of aging. Many professionals feel the term “disease” should be discarded. A better term might “progressive disc degeneration. Although we do know that discs can go through painful phases, there is not an accurate way of identifying that disc as being your source of pain at a specific point in time. Many other tissues in and around the spine can cause the clinical symptom of low back pain. So both from a anatomic diagnosis and clinical picture standpoint, there is not basis for classifying degenerative disc disease as a structural problem.

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