Radiofrequency Ablation and Facet Joint Injections
Chronic Lower back and neck pain are frequent complaints in my pain management practice. While pain radiating into the arm or leg is frequently related to disc herniation or spinal stenosis resulting in nerve pain(sciatica) those that just have pain in their backs often times are misdiagnosed as having muscle strains. The joints in the spine, also known as facet joints, are just like any other joint in the body, e.g. elbow, hip or knee and therefore they can be injured or suffer from osteoarthritis. While the pain from spinal joints can radiate away from the spine the major complaint is that of localized back or neck pain. Just like osteoarthritis of the knee can respond positively to a cortisone injection the same thing can occur with injections into the joints of the spine. There are two different methods for treating facet joint pain. The first is simple cortisone injections performed under x-ray guidance. The second and more preferable method is radiofrequency ablation (RFA) of the small nerves that go to the facet joints known as medial branches. RFA is a more specific and reliable procedure and some patients can get a year or more of relief of their back pain. Before I go any further I want to review basic spine anatomy so it will be easier to understand the treatment of facet joint pain.
Anatomy of the spine
The spine is frequently thought of as a very fragile structure but that could not be further from the truth. The spine is one of the most stable structures in the human body and believe or not it gets stronger with movement and weaker with rest.
I like to think of the spine as 24 flexible chain links in a very strong chain. The 24 links or vertebrae make up the neck, mid back and lower back or cervical, thoracic and lumbar spines. Below the lumbar spine is the sacral spine and the tailbone or coccyx. The vertebrae in these two areas are fused together and therefore do not move.
Sections of the spine
- Cervical- 7 vertebrae
- Throacic- 12 vertebrae
- Lumbar- 5 vertebrae
- Sacral- 5 fused vertebrae
- Coccyx- 2-3 fused vertebrae
At the front or anterior aspect of the spine there is disc material that lies sandwiched between each vertebrae. The one exception is between the first and second cervical vertebrae where a disc is not present.
There are two facet joints in each spinal segment. The function of each pair of facet joints is to guide and limit movement of the spinal at that segment. A small capsule surrounds each facet joint providing a nourishing lubricant for the joint. Also, each joint has a rich supply of tiny nerve fibers that relays a pain signal to the brain when the joint is injured or irritated. Just like any other joint in the body, facet joints are subject to degeneration, inflammation, fracture, injury, and arthritis.
Radiofrequency Ablation and Facet Joint Injections
Through multiple medical studies it has been determined that somewhere between 25-30% of patients with chronic lower back pain have their pain coming from the facet joints. The two types of spinal procedures that can be performed to help eliminate or reduce joint pain are radiofrequency ablation and facet joint injections with corticosteroids. The former is the currently preferred form of treatment as it tends to be a more focused and reliable treatment.
Facet Joint Injections
Facet joint injections are used to diagnose and treat painful and inflamed joints in the spine. Using real time low dose x-ray guidance known as fluoroscopy a needle is placed into the joint or joints that are suspected to be painful. In some instances a small amount of contrast dye will be injected to ensure proper needle tip localization and then a mixture of lidocaine (local anesthetic) and a steroid is injected. Most individuals begin to see benefits after 3-5 days but it can be up to two weeks for others. If beneficial these injections can be repeated a few times in a 12 month period.
Potential Risks of Facet Joint Injections
The risks of facet joint injections include bleeding and infection as well as potential side effects from the steroids used. To reduce the risk of bleeding certain medications and supplements must be stopped prior to the procedure. Please see the pre-procedure instructions for a partial list of these medications. If you are uncertain about whether you should stop a medication before your procedure it is best to call Dr. Sobel’s office and ask.
Radiofrequency Ablation for Facet Pain
Radiofrequency ablation (RFA) is a type of injection procedure used to treat facet joint pain caused by arthritis or other degenerative changes, or from an injury.
In this procedure, a heat lesion using radiofrequency energy is created on certain nerves with the goal of interrupting the pain signals to the brain, thus eliminating or reducing pain.
For those with lower back or neck pain the radiofrequency ablation is performed on the medial branch nerves which carry pain impulses from the facet joints. There are two primary types of radiofrequency ablation.
These medial nerves do not control any muscles or sensation in the arms or legs, so a heat lesion poses little danger of negatively affecting those areas. The medial branch nerves do control small muscles in the neck and mid or low back, but loss of these nerves has not proved harmful.
Diagnostic Medial Branch Block
Before the radiofrequency ablation procedure, a diagnostic medial branch nerve block will need to be performed to prove that the patient’s pain is coming from the facet joints. In this procedure the same medial branch nerves that may be treated with RFA are numbed up with a local anesthetic and then the patient fills out a pain diary for 5 hours afterwards. If there is pain relief from this procedure then the person is a potential candidate for radiofrequency ablation.
Radiofrequency Ablation Success Rates
Success rates vary, but typically about 30% to 50% of patients undergoing this procedure for low back pain will experience significant pain relief for as long as two years. Of the remaining low back pain patients, about 50% will get some pain relief for a shorter period. In my personal experience, the percentage of patients getting relief can also depend on how well the diagnostic injections are performed and how closely the physician follows the guidelines which recommend the use of pain diaries after the procedure and no sedation during the diagnostic injections.
There are however, some patients do not experience any relief from pain as a result of this procedure and they had positive diagnostic injections.
Overall, success rates are greater in the cervical spine (neck) than in other areas.
As a general rule, if effective, the ablation will often provide pain relief lasting at anywhere from 6 to 18 months and sometimes for longer. After this period of time, however, the nerve will regenerate and the pain may return.
Side Effects of Corticosteroids
All corticosteroids have potential side effects. These tend to range from uncommon to rare but can occur and you need to be aware of them. They are usually much less prevalent than the side effects from taking oral steroids.
- Facial flushing
- Fluid retention
- Elevated blood pressure
- Fever the night of injection
- Elevated blood sugar for 2-3 days- diabetics need to monitor their blood sugars closely
- A transient decrease in immunity because of the suppressive effect of the steroid
- Heartburn/stomach ulcers
- Severe arthritis of the hips (avascular necrosis)
- Post-injection flare – an increase in pain that can occur several hours after the injection and can last for several days