Low Back Pain, and Diagnostic findings in 40 year olds
Every day, I have consultation with patients that have had lumbar MRI’s, but with mild complaints. Some primary care physicians use CT scans to identify causes of low back pain. Fortunately, while there are some findings on the studies, it is rare to find a truly emergent finding. Also, it was rare to find a truly “normal MRI” as most of my patients are in their 40’s and 50’s. As a Physician, we often wonder what are the true rates of lumbar MRI findings for the average middle age population.
We are fortunate that there was a study performed investigating that specific concept.
It was a fascinating population study located in Funen County, Denmark. Every ninth person who was born in Denmark between 5/27/1959 and 5/26/1960 who also resided in Funen county was contacted by mail. In other words, 40 year olds at the time of the study.
Anyone with severe disability, magnetic implants, claustrophobia, or inability to communicate in Danish were excluded. 625 subjects were contacted by mail. 413 (66%) agreed to participate in the study. Each participant filled out a questionaire. Each participant was also given a lumbar MRI ( .2 T magnet). The questionaires were tabulated, and the MRI’s interpreted by a defined group of radiologists. Interobserver reliability parameters demonstrated a greater than 98% agreement by the reading radiologists.
The questionaire reflected a 69% incident of back pain in the prior year for all participants. Disk related findings such as herniations, bulges, disk narrowing, etc was found between 25% to 74% of the finding per participant.
There was a weak association between hypointense disc signal, reduced disk height and Modic type changes.
To me, the take home message from this study are the following:
Low Back pain is a common experience for 40 year olds.
Disk abnormalities at age 40 is very common.
MRI’s are not very specific, in terms of determining the cause of low back pain.
I did not need a scientific study to confirm what I already knew as a practicing spine specialist. But I am glad the science confirmed my conventional thoughts about the topic.