If you’ve been keeping up with our blogs recently, you might remember when we first discussed the variety in the kinds of treatment for back pain. There are three major non-surgical categories in the treatment of low back pain: therapy, medications, and injection/procedures.
We now turn our discussion to the third and final non-surgical pillar of treatments which includes injections and other minor procedures that I do not classify as “surgery”. We will follow the list of low back pain causes that we previously outlined, and discuss what injections might help those issues.
Before we look at each injection’s specific benefits and risks, I will broadly state a few characteristics that are present for all procedures. One of the most common questions asked regarding a procedure is how long the benefit will last. If the procedure involves the injection of steroids, a positive response generally lasts between 3-6 months.
There are certainly patients who receive a longer benefit and there are unfortunately patients who receive a shorter benefit. Some patients may not see benefit from the steroid until 7-10 days have passed since the injection. With steroid injections, if a patient receives at least 3 months of benefit, most will be able to repeat this injection in the future when the beneficial effects fade.
If the injection only contains local anesthetic (numbing medicine), then this is a test (diagnostic) injection and will last for roughly 6-8 hours. This short duration is expected and normal in a test injection. The goal of this type of injection is to prove that the pain improves for the duration of the numbing medicine (i.e. while the targeted nerves are numb). Some patients may feel as though they are worse after a test injection wears off because they have had a brief period without pain. When the pain returns it may seem worse than they remember as a result though this is unlikely the case. The final duration is regarding nerve ablations which generally will last around twelve months. There will be more on what an ablation entails below.
The second broad characterization will be regarding the risk associated with procedures. Anytime a needle is placed through the skin there is a risk of bleeding or infection. There is also a risk of damage to the structures surrounding the procedure’s target site. The risk of bleeding is higher for those who are on blood thinners which is why you may be asked to stop certain blood thinning medications prior to your procedure. To mitigate the risk of infection, procedures are performed in an operating suite under sterile conditions similar to those used in surgery. The final broad risk is a reaction to one of the injected medications. The most common of which would be the flushing and agitation with steroids as described in the article on medications. We will now look at specific procedures in greater detail.
Treating Facet Joint Pain
Facet joint pain can be targeted in two main ways. The first is an injection of steroids into or around the joint. The second involves ablating (burning) the nerves that bring the pain information from the joint to the brain. Another term that is used commonly for this procedure is a rhizotomy. Prior to burning the nerves, two test injections are performed on two separate occasions. If the tests are successful, then at a subsequent visit a special needle is inserted along the course of the nerve. This needle’s tip heats up and burns the nerve. Pain relief lasts until the nerve regrows. All three of these injection types are done utilizing x-ray guidance. The most common side effect specific to these injections is soreness in the area of an ablation. When the needle heats, it heats all of the tissue in the area, not just the nerve. Generally this soreness goes away in several days and is helped with ice and over-the-counter medications. A less common side effect is called “post-ablative neuritis” which is a medical way of saying that the nerve becomes irritated and painful while it slowly stops working. This should be discussed with your provider should the above listed conservative treatments not adequately control your post-procedure pain.
Treating Sacroiliac Joint Pain
Sacroiliac joint pain can be treated much the same way as facet pain. Injection of steroids into the joint itself can be done with either x-ray or ultrasound guidance. Should this fail to provide durable benefit, then just as with the facet joints, the nerves that bring pain information from the joint can be ablated. Performing an ablation on the sacroiliac joint is different when compared to the facet joint because it is much larger. Additionally, there are nerves that bring pain information from the front aspect of the joint as well as the back aspect. Unfortunately, the only nerves that can be targeted are the ones on the back side. Therefore, some patients may not get as much relief with an ablation for this joint if their pain is located closer to the front aspect of the joint. The same side effects exist for these procedures as those above for the facets.
Treating Back Pain Caused by Spinal Discs
Disc degeneration, spine related sciatica, and neurogenic claudication can all be discussed as one entity because the main injection used in their treatment is the same: an epidural steroid injection. This injection can be accomplished in one of three different ways. All three involve the injection of steroids into the epidural space which is the space surrounding the spinal cord and nerve within the spinal canal. They differ in how the needle is advanced into this space, either from the holes (foramen) on the side, the holes on the back (interlaminar space), or at the bottom of the spinal column (sacral hiatus). X-ray guidance is used for each of these and once the needle appears to be in the correct spot, injection of contrast dye through the needle confirms correct placement prior to injecting the steroid. The risks are the same as the general risks listed above. Different from the prior injections is the fact that there are structures at risk of direct damage from the needle in the form of the nerves and spinal cord. This risk is very low and is the purpose for the use of the x-ray and dye however, should it occur it would usually manifest as numbness, tingling, or perhaps weakness beyond the duration of the injection.
Treating Soft Tissue Pain
Soft tissue pain, such as a muscle strain or spasm, is usually best treated with therapy and medications. However, there are times when the pain is so severe that those treatments are either not helpful or not possible at the moment due to the pain. The main injection that can be of benefit would be trigger point injections. This entails injecting a combination of a numbing medicine by itself or usually with either a steroid, a muscle relaxing medication, or a nonsteroidal anti-inflammatory drug. The only risk beyond the general risks stated above would be when the muscles causing the pain are higher on the back and thus over the area where the lungs are located. In this case, there would be a risk of accidentally placing the needle into the lung/chest cavity and causing air to leak from the lung and build up between the lung and the chest wall causing chest pain and potential problems breathing.
Treating Vertebrogenic Pain
Vertebrogenic pain can be treated via a similar concept as the ablations used for facet and sacroiliac joint pain that is called basivertebral nerve ablation. The difference is that a test block is not performed, rather other potential sources of the pain are ruled out first. The basivertebral nerve ablation procedure involves placing a wire along the base of the vertebrae that will heat up to destroy the nerves in that area. In order to place this wire, a larger needle must be placed through the bone from the back side. The main risk beyond the general set is related to the placement of this large needle through the bone and ensuring that it stays within the bone and does not push through into the spinal canal. Again, as with most of these injections, extensive x-ray guidance is used to ensure the utmost safety.
Fractures of the vertebrae can be treated conservatively with a back brace to limit mobility much like a cast around a broken arm with medications to ease the pain while healing occurs. In some cases, it may be better to “cast” the bone from the inside. This procedure is called vertebral augmentation and more specifically a balloon kyphoplasty. This involves placing a needle through the bone similar to basivertebral nerve ablation through which a balloon is passed. The balloon is then inflated to make a cavity into which bone cement is placed adding stability to the fracture. The risks are similar to the basivertebral nerve ablation regarding placement of the needle with the added risk of cement leakage beyond the boundary of the bone. Again, this is why constant x-ray guidance is used to ensure safe performance of the procedure.
This concludes our discussion about the causes and non-surgical treatments available for low back pain. As stated in prior articles, the above list is not exhaustive but hopefully serves as a good reference.