Key takeaways
- Disc bulges and degeneration are very common on MRIs of people with no back pain at all, and become more common with age.
- A finding on your MRI may or may not be the source of your symptoms.
- The diagnosis comes from matching your history and exam findings to the imaging.
- Treatment aimed at the wrong finding is one reason some back care, including surgery, doesn't work.
"I know what's causing my back pain. My MRI shows a herniated disc." We hear this often, and it's completely understandable. When you see a bulge on a scan, it seems like the answer.
Sometimes it is. But sometimes the exam tells a different story: the symptoms are on the right side while the herniation is on the left, or the herniation is at a different level from the nerve that's actually irritated. In those cases the disc on the MRI isn't the cause at all.
MRI findings are common, even without pain
Large studies of people with no back pain have found that:
- Disc degeneration shows up in about a third of 20-year-olds and in the large majority of people over 60.
- Disc bulges are found in roughly 30 percent of people in their twenties and more than three-quarters of people in their seventies and eighties.
- Disc protrusions and small herniations are also common in people with no symptoms.
(These figures come from a large 2015 review of imaging studies in people without back pain, published in the American Journal of Neuroradiology.)
In other words, many MRI findings are a normal part of aging, much like gray hair. They can be the cause of pain, but they aren't automatically.
Why this matters
If treatment is aimed at a finding that isn't causing your pain, it's unlikely to help, and the real problem goes untreated. This is one of the reasons some injections and surgeries disappoint (see Do you really need back surgery?).
How the real cause is found
The diagnosis comes from putting several pieces together:
- Your history - when it started, what makes it better or worse, where it travels
- A detailed exam - reflexes, strength and sensation in specific nerve patterns, plus movement and orthopedic tests
- Imaging - reviewed against the exam, to see whether what's on the scan matches what your body is telling us
That's why our evaluation is split into two visits. On the first, we take your history and do a thorough exam and testing. Dr. Le then studies your imaging, and on the second visit he explains the findings, the diagnosis and the plan, including whether what's on your MRI is truly the source of your pain.