MRI Findings in Brain May Predict Lasting Back Pain

MR imaging may help physicians predict which patients with lower back pain will continue to experience persistent pain, according to a study published in the journal Pain.

Treating chronic pain is costly, an estimated $635 billion per year in the United States. About 28 percent of pain in the United States is related to back pain and among these people, 23 percent experience long-term pain.

In 2012, researchers from Northwestern University Feinberg School of Medicine in Chicago, Ill., found multiple white matter axon bundles, with some surrounding the nucleus accumbens and medial prefrontal cortex in patients with back pain. This current study identified a pre-existing cause for these findings.

To determine if the abnormalities had prognostic value, researchers followed 46 patients who had presented with at least one episode of lower back pain that lasted for at least four weeks (with a minimum 5-out-of-10 rating on the pain scale), but had not experienced any pain for at least one year prior. The patients underwent MR imaging at study onset and one year later.

Results showed approximately half of the patients showed improvement after a year, whether they took medication or not, and the rest did not improve. Imaging showed the patients with persistent pain also had the same structural abnormality in their white matter at onset of injury and after one year.

“The abnormality makes them vulnerable and predisposes them to enhanced emotional learning that then amplifies the pain and makes it more emotionally significant,” said senior author and Northwestern physiology professor A. Vania Apkarian, PhD.