Diagnostic Injection for Low Back Pain from the Facet Joints May be Unnecessary

New research questions cost-effectiveness of administering diagnostic injection prior to treatment
Diagnostic Injection Image

A new study performed at John Hopkins Medical Center and Walter Reed Army Medical Center suggests the current process of treating axial lower back pain caused by the facet joints is not the most cost-effective.

Axial lower back pain is the second most common reason for visits to pain clinics. It is estimated that facet arthropathy is the cause of pain for ten to fifteen percent of these patients. Facet arthropathy is the degeneration of the facet joints, more commonly referred to as spinal arthritis. The initial treatments are physical therapy, exercise, pain medication, and heat or cold therapy. When those do not provide lasting pain relief, the primary interventional treatment for facet arthropathy is radiofrequency neurotomy. Radiofrequency neurotomy is where an injection is used to burn nerves in the facet joint in order to stop the body from sending pain signals to the brain.

Current guidelines suggest using diagnostic nerve blocks to confirm the joint is the cause of pain before the radiofrequency neurotomy procedure is done. In these diagnostic tests, an anesthetic is injected into the facet joint and if the pain is relieved, the doctor and patient will know there is a problem with that joint causing the pain. Guidelines also call for a second confirmation diagnostic block before radiofrequency neurotomy is done.

In this study, the researchers studied the cost-effectiveness of using one diagnostic test compared to two diagnostic tests and no diagnostic test. In the group where no diagnostic test was performed, every patient was treated with radiofrequency neurotomy. In the study of 151 patients, the average cost for just a diagnostic nerve block was higher than the cost for the radiofrequency neurotomy procedure. Also, more total people in the group with no diagnostic test had their back pain relieved by at least 50 percent than groups where diagnostic tests were given. This is believed to be due to the population of people who do not have a positive diagnostic test but still end up experiencing pain relief as a result of the radiofrequency procedure.

The researchers suggest reconsidering the guidelines for treating facet arthropathy. Their conclusions show treatment without diagnostic tests have a lower cost to the healthcare system and result in more patients experiencing relief of their pain. The point of the diagnostic test in this case is to confirm that the facet joint is in fact the cause of the pain, which helps avoid unnecessary neurotomy procedures. Their recommendation would treat more people through radiofrequency neurotomy and less people would be tested using diagnostic nerve blocks.

The risks of a radiofrequency neurotomy injection are localized pain at the injection site, chance of bleeding or infection, allergic reaction to the injected material, and skin numbness. There is a chance the injection can cause muscle spasms at the injection site and create more pain rather than relief. There is also a remote chance of damage to the spinal nerves from the needle or the injected material, causing permanent pain. These are similar to the risks of the diagnostic nerve block injection, where the injection procedure risks are the same, but there are fewer risks from the injected material causing nerve damage, muscle spasm, or skin numbness and different allergies will trigger a reaction to the material.

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