Insights into why some back pain becomes chronic



Back pain is a common condition for Canadians. It can occur anywhere in the spine. Characterized by pain, muscle tension, stiffness, weakness in feet and legs, and tingling and burning symptoms it can become debilitating. It is often caused by stress on the muscles and ligaments that support the spine, traumatic injury, or by degenerative conditions like spinal stenosis.

Back problems are among the most common chronic conditions in Canada. Four out of five adults will experience at least one episode of back pain at some time in their lives,10-13 although the occurrence is most often between the ages of 30 and 50. Back problems appear with equal frequency in men and women.

The cause of the pain isn’t always apparent, in fact according to Statistics Canada up to 90% of people with back pain can’t identify a specific cause. 

Treatment for back pain often includes anti-inflammatory drugs for acute pain. For severe cases opioids are sometimes prescribed leading to other complications. Other treatments include spinal nerve blocks, exercise, chiropractic treatment, physiotherapy, strengthening exercises and acupuncture.

The CBC News reported this week on a new joint study from McGill University and Italian scientists which suggests that blocking inflammation after injury to the spine may lead to the development of chronic pain.

Here is an excerpt from the CBC article , Adam Miller

In this study, researchers found that neutrophils, a type of white blood cell that helps the body fight infection and dominates the early stages of inflammation, play a key role in resolving pain.

Jeffrey Mogil, researcher of the study and professor of psychology at McGill University, says standard medical practice for treatment of short lasting pain after injury might be the opposite of what we should be doing.

"We think that chronic pain develops because of inflammation so we think inflammation is bad and we should stop it. But what this study suggests is that yes, but at the cost of increasing your chances to develop chronic pain," Mogil said.

While the findings have not yet been tested on humans in a clinical trial, several pain experts that are not affiliated with the study say it suggests a new way to look at how the body heals.

The study, which was published in Science Translational Medicine last Wednesday, was conducted by nearly two dozen researchers who examined pain in three phases, using human blood cells and mice trials 

They examined the blood cells of 98 patients with acute low back pain and looked for markers of inflammation. Three months later, they did the same test — comparing those who still had persistent pain and those who didn't. 

The patients whose pain had gone away showed more inflammation on the first visit, which seemed to be driven by neutrophils, a type of white

"People who didn't resolve their pain, absolutely nothing happened in their blood," said Dr. Luda Diatchenko, another researcher of the study and professor of dentistry and medicine at McGill University. Both groups of patients used anti-inflammatory drugs, she said. 

Researchers tested on mice and confirmed that blocking inflammation using drugs relieved them of pain short term, as judged by their sensitivity to touch. But the drugs prolonged the resolution of their pain — turning the acute pain into something more chronic.

In the last phase of the study, they examined data of 500,000 people from the United Kingdom Biobank, a database of medical information obtained from half a million volunteers. 

Researchers found those taking anti-inflammatory drugs, like ibuprofen, naproxen, and diclofenac to treat their pain were much more likely to have pain two to 10 years later — a correlation that's consistent with their other findings, but can't determine what caused the ongoing pain.

They also found those who took other painkillers, such as acetaminophen (Tylenol), were less likely to have chronic pain compared to those who took anti-inflammatory medication. 

Dr. Hance Clarke, medical director of the pain research unit at Toronto General Hospital, says around 18 per cent of the population struggle with chronic back pain. 


Even without randomized clinical trials, Clarke said there are implications to understanding what happens differently between acute and chronic pain.

"This is a pretty landmark finding," he said in an interview with CBC News. 

"To find a molecular basis that relates to those who will go on to have a chronic pain problem versus those who are going to avoid that should be taken pretty seriously."

If you have sustained a serious back injury as a result of a car accident or slip and flal or workplace injury, please contact the experienced personal injury lawyers at Deutschmann Personal Injury and Disability Law today 1 (866) 414-4878

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