Physicians know that X-rays, CT scans, and MRIs don’t really contain the rest of the story. Many patients have all kinds of changes in the lumbar spine but no symptoms — no pain, no change in sensation. There can be narrowing of the disc spaces, spinal stenosis (narrowing of the spinal canal), spinal joint arthritis, and even tiny fractures called spondylolysis but no one knows about it until X-rays or other imaging studies are done for something else.
Most of the folks who have what looks like significant changes of this type in the spine are older adults (65 years old and older). Low back pain can be a common symptom in this age group. So, how much of these changes (and which ones) are linked with back pain? That’s what this group of researchers set out to discover.
They used a group of patients already enrolled in the world famous Framingham heart studies. Those individuals live in Framingham, Massachusetts and participate in a lifelong study of health (especially heart health). In the process of being examined, they each have CT scans done to look for blood vessel calcification (hardening and blockage of the arteries). The imaging studies also showed the structures of the spine, which were analyzed for this study.
The advanced imaging showed a wide range of degenerative changes as described above. Most notable was the high incidence of disc narrowing and spinal joint arthritis observed in two-thirds of the group. The researchers then started analyzing data collected about the patients to see if there were any links between low back pain, age, gender, and body mass index with degenerative structural changes in the spine.
What they found was that only spinal stenosis was significantly associated with low back pain. Disc narrowing, facet (spinal) joint arthritis, changes in the spinal muscle size, and spondylolysis were NOT directly linked with low back pain. There was an association between low-density muscles of the spine (multifidus and erector spinae) and arthritic changes observed in the facet joints. Exactly what that means remains to be determined.
The results of this study don’t answer all the questions around low back pain and imaging studies. Physicians walk a fine line between using imaging to confirm a diagnosis and relying on imaging that could provide misleading information.
The hope is that results of spine imaging tests will help physicians select the most appropriate treatment for each patient. But it doesn’t always work out that way since so many studies have shown that it’s possible to have moderate-to-severe degenerative changes in the spine and still be completely pain free and unaware of those changes.
And this study confirms that even though CT scans provide much more anatomical information than standard (and less expensive) X-rays, the information should not be relied upon except as it concerns the presence of stenosis and low back pain. In other words, the presence of spinal stenosis predicts and confirms low back pain. Treatment directed at the cause of the pain (stenosis) may provide better outcomes for patients. Future studies to assess age-related changes in the soft tissues (such as the muscles) might yield additional valuable information.