Referred Pain: Can it be treated by Radiofrequency Ablation (RFA)?
Leg pain, arm pain, and even headaches can all be referred from the facet joints in the spine. These small joints connect each vertebral body. Like other joints in the body, the facet joints can wear out and develop arthritis (inflammation of a joint characterized by swelling and pain). Facet arthritis pain can refer to distant parts of the body as discussed in the article called "Sciatica: What is it?" If the source of this traveling pain is targeted, then vast swaths of pain can disappear. The newest invasive treatment actually targets the medial branch nerve that acts like a telephone line for the facet joint pain. When that line is cut, the pain signals from the joint cannot get through to the brain. The "cut" is actually a burn in the nerve. In other words, the nerve is ablated by radiofrequency heat--called Radiofrequency Ablation (RFA). Because the nerve can repair itself, this intentional injury is just a temporary disruption of the referred pain.
Ralph heard about Sally's leg pain. Unlike his cousin's leg pain, Ralph's leg just aches in the buttock without any numbness, tingling, or burning pain. Usually, his pain is worse when he has been standing for a long time. Occasionally, he feels a cramp in his calf. Every year, the pain just gets worse and worse. Ralph pleads with his doctor to "fix" the pain. His doctor suggested some "nerve blocks" that would determine if he was a candidate for a more permanent nerve burning procedure.
Blocks and burning; sounds very barbaric. But, this method is very sound in principle. Before sticking a heat probe (radiofrequency probe) into the spine, doctors first need to determine if a RFA has a good chance to relieve the pain. The first two blocks use temporary numbing chemicals to anesthetize the nerve. If the first one relieves 80% of the significant pain, then it is successful. But, to be sure, the injection is repeated to validate the initial results. The relief from the first two nerve blocks is time limited according to which chemical is used. With this screening method, only the patients with worthwhile relief will proceed to the nerve burning procedure--RFA. Under x-ray guidance, the heat probe is placed in the vicinity of the facet nerve. Zap, the nerve is burned so that the pain signals cannot get through to the brain. The facet joint will still have arthritis; only the pain is blocked.
After two successful trial injections, Ralph has the RFA procedure. As expected, the procedure has virtually eliminated Ralph's leg pain. Plus, his back moves better with less pain. His next critical questions for the doctor are: "How long is this going to last doc?" and "If the pain comes back, can I have another one?"
Ralph's questions are good ones because he knows that the nerve can repair itself. Once the connection between the joint and the brain is reestablished, the pain message will come through again, loud and clear. These questions are answered by the medical evidence. The research results on RFA are promising. At 12 months after the procedure, 60% of the people will have 80% relief. Keep in mind, that these results were produced with a very stringent selection criteria that picked the most likely patients for success. Since Ralph's doctor was diligent in his screening methods, Ralph is very likely to have good relief for at least a year. If and when the pain comes back, RFA can be repeated without accumulative risks.
Wow, Ralph is so pleased. He asks his doctor one last question: "Will this work for my buddy, Ron, who has neck pain radiating into his arm?" His doctor pauses with a bit of trepidation.
Trepidation is the key word when it comes to treating the cervical spine with RFA. Like the lumbar spine, the cervical facet joints can also cause referred pain. But, unlike lumbar facet pain, the cervical facets refer pain to the arms, shoulders, and head. And, unlike the lumbar spine, the medical evidence for RFA in the cervical spine is unclear. In fact, leading experts have proclaimed that there is no evidence to support the use of RFA in the cervical spine. Despite these words of warning, doctors still try to use RFA in the neck. However, the expectations are lower because the cervical spine facet joint and nerve is a much smaller target than the lumbar spine. The current RFA techniques just might not be accurate enough to hit the smaller target in the neck.
The facet joints are small, but produce a mighty pain that can refer to so many areas of the body. As technology improves, RFA could prove useful for both the cervical and lumbar spine. As technology improves, facet joint pain will one day be curable. For now, Radiofrequency Ablation is the best bet for referred pain that is not responding to non-invasive treatment.