Longtime followers will be well aware that chronic back pain is a widely prevalent, complex, and often disabling problem (see here, here, and here). A wide array of specialized interventions have been developed over the years, and many of these have taken hold in clinical practice without strong evidence for their effectiveness.
This paper discusses recent data from trials on radiofrequency denervation as a treatment for selected patients with chronic back pain. The idea is to identify a suspected structural “nociceptive driver”, such as an arthritic facet joint or sacroiliac joint. This peripheral focus of noxious stimulus is often also referred to as a “pain generator”, and then becomes the target for clinical intervention.
Radiofrequency denervation (also known as radiofrequency ablation or radiofrequency neurotomy) is a procedure by which an electrode is inserted and used to identify a suspected source of pain, and destroy the nerves believed to be transmitting “pain signals”. For a video explanation of this procedure, see here: https://www.ohsu.edu/xd/
Three recent trials took patients who had 1) a suspected peripheral tissue source of pain, 2) clinical response to a “diagnostic block” (i.e., improvement in pain after injection of a local anesthetic medication to the area), and 3) no comorbid mental health issues. These patients were then treated with radiofrequency treatment plus standard rehabilitation OR standard rehabilitation alone, and followed for 12 months. It should be noted that this style of study, comparing “A” versus “A+B” is often criticized because it is likely to inflate the apparent effects of “B”, since you are doing something “extra” to the treatment group, without a “sham” treatment in the control group. Despite the flaws of this design, the results still showed no significant benefit to radiofrequency denervation for pain or functional outcomes over the following 12 months.
Those who have followed developments in the field of pain neurobiology should not be surprised by these findings, as the premise of the intervention is based on a simplistic and outdated structurally-focused model of pain. The most important, take-home points from these trials reinforce central tenets of the biopsychosocial model of pain and modern pain neuroscience:
- Nociception (i.e., the sensation of a noxious stimulus) is not the same thing as pain.
- All pain is generated by the brain. There is no such thing as a tissue “pain generator,” or a peripheral “pain signal”.
Treating a suspected source of nociception does not guarantee (and often does not result in) pain improvement. As an aside, we see the same thing occur in numerous other contexts, for example the significant proportion of people who experience continued pain after total knee or hip replacements for severe osteoarthritis. The source of nociception (arthritic joint) is gone, but pain can often persist.
As we’ve discussed elsewhere, treatment of chronic back pain is far more complex than blaming and treating one specific structure. It requires comprehensive assessment of biological and/or structural factors, psychological factors such as catastrophizing, kinesiophobia, fear avoidance, and other associated beliefs/expectations from social contextual factors.
Link to Article:
Bagg et al. Recent data from radiofrequency denervation trials further emphasise that treating nociception is not the same as treating pain. Br J Sports Med 2018;0:1–2. doi:10.1136/bjsports-2017-
Austin Baraki, M.D.
Austin is a physician, veteran strength coach, and competitive powerlifter. He came to the sport of powerlifting after 15 years of experience competing in and coaching competitive swimming through the collegiate level. Transitioning to powerlifting, he has achieved personal best lifts of a 610 lb squat, 410 lb bench press, and a 665 lb deadlift. He is finishing up his final months of Internal Medicine residency in Texas while contemplating moving to the West Coast to continue his bromance with his salty compadre, Dr. Feigenbaum.