There is no question that performing multiple diagnostic facet blocks improves validity. The problem is the "cost" of this paradigm. Generally speaking, prognostic blocks are most useful when the treatment is much more expensive or has a higher complication rate than the blocks themselves, which is not the case for facet interventions. Therefore, the crux of the dilemma about how many blocks to perform before RF denervation comes down to this: Which do you view as more important, pain relief and functional improvement, or increased diagnostic accuracy? I believe most patients and doctors would choose the former.
In this large, randomized study, more people in the 0-block group experienced significant pain relief and functional improvement than in the 1- and 2- block group. Not only was the cost-per-effective treatment in the 0-block group less than half that of the other two groups, but the total cost was also less. In other words, less money was spent at current reimbursement rates to help more people. This is important when one is playing a "zero-sum" game.
Some experts might argue that some of the patients who proceeded straight to RF denervation may have been placebo responders. This may be true. But the decrease in pain, improvement in function, duration of benefit, and even changes in brain metabolism are indistinguishable between patients who improve from placebo and those who improve from "real" treatments. Some estimate that up to 50% of the effect of any pain treatment stems from the placebo response, which is stronger for injections than for medications, and can be repeated with comparable efficacy. Others might contend that performing two blocks is the only way to reduce the high "false-positive" rate of uncontrolled facet blocks or RF lesioning. The flip side of this argument is that the more blocks one does, the higher the "false-negative" rate becomes, which is poor tradeoff. In my opinion, I would rather do an incredibly safe RF procedure on someone who may not have the index condition, than withhold this treatment from someone who could benefit.
Steven P. Cohen, M.D., Johns Hopkins School of Medicine, Baltimore, MD
About the Author
Dr. Steven Cohen obtained his medical degree at the Mount Sinai School of Medicine in New York City, completed his anesthesiology residency at Columbia University, and a pain management fellowship at Massachusetts General Hospital. Currently, he is Associate Professor of Anesthesiology at the Johns Hopkins School of Medicine and the Uniformed Services University of the Health Sciences. In addition to his academic work, Dr. Cohen is a Colonel in the U.S. Army Reserve and serves as Chief of Anesthesia & Operative Services at the 48th Combat Support Hospital at Fort Meade, MD, and Director of Chronic Pain Research at Walter Reed Army Medical Center in Washington, DC.
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