By The Numbers: "2"


"2" is the number of medial branch blocks (MBB) that should be “successfully” completed prior to performing a radiofrequency ablation (RFA) procedure. Getting two successful injections in a row is not nearly as easy as you might think. It depends greatly on how well the provider administering the injections has clinically examined the claimant.


Overview: Medial Branch Blocks

First, a little background. The medial branch block is primarily used as a diagnostic procedure. It helps diagnose whether the medial nerves that innervate a facet is the source of pain. A provider does not perform diagnostic medial branch blocks for their own sake. They are used to confirm which branch or branches of nerves are the proper target for an RFA. Because the RFA is the ultimate procedure, there should be agreement, in advance, that an RFA will be completed if the MBBs are successful.

Across the industry, we see more and more medial branch blocks being performed. In many cases, there is no ablation procedure that follows. In order to effectively review these cases, it’s critical to know details on when and how these procedures should be considered.


Here are a few items to keep in mind: 1. The general recommendation is to wait more than 6 months before considering MBBs and RFA. This should follow failed conservative care. Most back pain resolves over time. Pain emanating from facet joints is typically very responsive to effective physical therapy. How long has it been since the accident? 2. Medial branch blocks are successful if they provide immediate pain relief. This should be clearly documented as part of the procedure. 3. The second block is performed (generally at least a week later) into a specific facet when the first block is successful. It is important that there be “2”. There is a high rate of false positives with this process, so being able to demonstrate relief in two consecutive procedures is important. The success of the radiofrequency ablation that follows is significantly higher when two successful injections have been delivered. “Success” means greater than 80% relief. 4. A patient receiving these blocks should not be sedated. If the patient is sedated, it can produce a false positive result from the procedure. In a block procedure, the provider injects an anesthetic drug whose effects are immediate. As the provider is injecting the anesthetic, he or she questions the patient about their pain levels. If there is relief, the provider has good information about the likely cause of pain. However, if the patient is sedated, they will have reduced pain and their response to the block procedure will be unreliable. 5. Locating the correct site for injections is not easy. The literature consistently indicates that these injections have some success with well-selected individuals.Diagnostic tools such as MRIs, CTs or x-rays, even those showing arthritis and other degeneration, are not reliable in identifying the source of the pain. In fact, distinguishing between facet pain and common strain/sprain injuries can be very difficult. How well does the provider document their findings and the basis for the level(s) they choose to inject? 6. The vagueness of the diagnosis, though, should NOT be viewed as making their necessity difficult to challenge. To the contrary, the opposite is true. The difficulty in being right raises the bar for the provider indicating that the MBBs are necessary. Pointing out the inadequacies of the examination leading to the recommendation is a key element in shifting the burden back to the provider. What You Need to Know

A little more background. Some providers will attempt “therapeutic” facet injections. The evidence for performing these is mixed. Also, medial branch blocks are fundamentally different from epidural steroid injections (ESIs). ESIs are performed to address impingement of a nerve root. They are therapeutic in nature, not diagnostic. When you see injections, your reaction should not be to groan, but, instead to dig in. The analysis needed to reach effective conclusions such as those described above takes time and training to complete. Proper analysis leads to finding medically unjustified injections at a much higher rate than most would expect.

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