"Did you hear about the study of the MRIs and herniated discs?" It was 1995, I was working at St. Mary's Hospital, and one of my fellow massage therapists had news about a surprising piece of research. In those days before the internet it was difficult for us to get information about studies of interest to us massage therapists. A juicy tidbit like this was cause for excitement.
A team of researchers had examined 98 people with no back pain. MRIs revealed that over half of them had at least one herniated disc and almost 40% of them had disc abnormalities of more than one disc. I found this piece of news stunning. Herniated discs were often blamed for low back pain. What this study showed was that half of adults may be walking around with at least one herniated disc . . . but no pain! If any of those individuals developed back pain and an MRI revealed a herniated disc, it would be assumed this would be the cause of the pain. However, since it would be unlikely for a person without pain to have an MRI, it could very well be possible that the herniated disc had existed for years. Clearly, the presence of a herniated disc did not have to correspond with pain.
I thought this news would send shock waves through the orthopedic, physical therapy, and pain management communities. I guess I was pretty naive. It is now 2013, almost 20 years later, and every day people with back pain continue to be told that their pain is due to a herniated disc. What is that all about?
Even in 1994, this study stated that "The presence of disc abnormalities in the lumbar spine of asymptomatic people is well known." Subjects in that particular study ranged in age from 20 to 80 years old. Although the presence of bulges and protrusions increased with age, the study includes an image of a disc protrusion in the lumbar spine of a 21 year old man who had no back pain. Other studies using MRIs, CAT scans, myelograms, and post-mortem examinations had found disc abnormalities in 20 to 60 percent of individuals who did not have back pain.
Five years before, in 1989, a study examined sixty-seven individuals with no history of back pain and found that 31% of them had disc abnormalities. A follow-up study seven years later found that some of the original subjects had developed back pain but there was no correlation between the presence of a herniated disc and back pain. Some people with herniated discs developed pain, some did not. Some peope without herniated discs developed pain, some did not. The percentages were about equal.
One or two studies are not enough to prove a point, but study after study has shown that there is little to no correspondence between low back pain and herniated discs.
A recent (Mar. 14, 2013) study published in the New England Journal of Medicine has again reinforced what has now been known among pain researchers for at least 20 years: that the presence of a herniated disc is not predictive of low back pain. Two hundred eighty-three patients entering a clinic for low back pain were examined. Some had herniated discs, some did not. After one year, 84% had complete or near complete disappearance of their pain. Reexamination with MRI found that disc herniations were still present and were just as likely to be found in those with pain as in those with no pain. The presence of herniated discs seemed to have no correspondence with whether people had pain, their degree of pain, or whether they got out of pain.
Why are people still being told that their back pain is due to the presence of a herniated disc when it has been clearly shown, over and over, that there is no correlation?
And why are MRIs still routine when it been shown that not only are they not necessary, they may actually interfere with resolving back pain?
We'll continue to look at this and a few other questions in our next article.