New test to diagnose back pain better

Boston, April 8: Researchers at Massachusetts General Hospital in Boston have found a simple and cost-effective test to differentiate between non-neuropathic and neuropathic back pain.

As per the researchers, the test named StEP (Standardized Evaluation of Pain) can be better than the commonly used methods in determining the exact nature of the back pain, which can further help to decide on the appropriate treatment option.

StEP, taking just 10 to 15 minutes, can help distinguish between those suffering from neuropathic radicular back pain and non-neuropathic axial back pain with high sensitivity and specificity.

On the other hand, the currently used tests take anything between 60 to 90 minutes to do the complicated assessment.

According to Joachim Scholz, MD, the lead author of the study, “Currently, clinicians measure pain only by asking how bad it is, using scales from mild to moderate to severe, or by asking patients to rate their pain from 1 to 10. This approach misses key characteristics that reflect the mechanisms causing the pain.”

A senior investigator and director of the Neutral Plasticity Research Group at Massachusetts General Hospital, Clifford Woolf, MD, PhD, says, “By evaluating individual components of pain, our method allows the creation of a ‘pain fingerprint’ for each patient.”

For the study, the researchers enrolled 187 patients suffering from chronic back pain. Out of the group of 187 patients, some were suffering from low back pain while others had neuropathy associated with shingles or diabetes.

The participants were asked to undergo an extensive medical history and physical examination, including 20 simple tests which were quite simple to conduct at bedside.

The purpose of the analysis was to diagnose the peculiar symptoms and signs that could prove helpful in knowing the underlying pain mechanisms.

Based on the findings of the analysis, StEP was developed which includes a set of six interview questions and 10 physical tests that can help in differentiating between neuropathic and non-neuropathic pain. StEP was successful in identifying patients suffering from radicular low back pain with high sensitivity (92%, 95% CI 83% to 97%) and specificity (97%, 95% CI 89% to 100%).

The most common type of back pain is axial back pain which is non-neuropathic. It means that the pain is not caused by damage to the nervous system or spinal chord. On the other hand, radicular low back pain, also known as sciaticadefine, often radiates from the back into the legs and is neuropathic.

“This distinction is crucial,” the researchers maintained. “It is often difficult to decide which patients will benefit from treatment strategies that target neuropathic pain,” agreed the researchers who felt that StEP was much better than the current test for neuropathic pain, including MRIdefine of spine.

“The treatment of neuropathic and non-neuropathic pain is quite different, and if a diagnosis is wrong, patients may receive treatment, including surgery, that does not improve their pain.

“We showed that StEP is a valuable diagnostic tool for low back pain and will conduct further studies to determine the usefulness of our clinical approach in other types of pain.

”The critical test will be seeing how patients with different subtypes of pain respond to different treatments, something we hope to examine in the very near future,” added Scholz.

Researchers said that further studies are needed to determine the accuracy of StEP for the distinction of neuropathic and non-neuropathic pain.

The study is published in the April 7 issue of the journal PLoS Medicine.