Injections in the sacroiliac joint are both diagnostic and therapeutic. If you suffer from chronic lower back pain, your doctor may suggest a sacroiliac joint injection to help determine the source of the pain. The injection may also provide immediate pain relief.
The Sacroiliac Joint
The sacrum is a set of fused vertebrae at the lower end of your spine. The ilia are the bones of your pelvis that are next to your spine. The sacroiliac joints are where the spine and the pelvis meet. There is one of these joints on each side of your spine.
Pain in your sacroiliac joints can have a variety of causes. The most common is degenerative arthritis. In this condition, the cartilage that normally cushions the bones where they meet has begun to deteriorate. This often happens with age, but can also be the result of an injury. As the bones begin to rub against each other, you can experience pain.
It is also possible that an injury or other joint dysfunction is causing inflammation in the joint. The cartilage can swell, pressing on the nerves in the area and causing pain. This sometimes happens as a result of the way you walk or move. For example, if one of your legs is shorter than the other, a lifetime of uneven stress on the sacroiliac joints may eventually become painful. An injury at any point in your life that changes your gait can also cause you to shift your weight in ways that stress these joints. Whatever the cause, the pain is usually felt as chronic lower back pain or sciatica.
Sacroiliac Joint Injection Procedure
If non-invasive diagnostic techniques like MRI or CAT scans have not told your doctor where your lower back pain is coming from, a sacroiliac joint injection may be the best next step. If the injection relieves your pain, your doctor knows that that is the problem area and can plan a course of treatment accordingly. If the injection does not relieve your pain, your doctor knows to keep looking.
The injection procedure is done in the doctor’s office, and you will go home the same day. Light sedation is optional. It can help you relax, but it is not required. You will lie on your stomach on a table with appropriate monitoring devices attached to your body. The injection site on your back will be numbed with a local anesthetic. Usually only one joint, either the left or the right, is treated at one time. It is often only one side that is producing your pain.
The first thing your doctor will do is insert a long, thin needle into your sacroiliac joint and inject a test dye. A fluoroscopy allows the doctor to see exactly where the needle is placed and how the dye is spreading. Once the doctor is sure that the needle is in the right spot, and the amount to be injected will only affect the desired area, an anesthetic is injected into the joint.
If the injection is being done as a diagnostic test, you will be asked to perform the movements that were causing your pain. If you report pain relief of about 75 percent, that is taken as a sign that the sacroiliac joint was, indeed, the source of your pain.
If the injection is done as a treatment, an anti-inflammatory steroid will be injected along with the anesthetic. You will have immediate pain relief from the anesthetic, which will wear off after a few hours. The steroid will reduce the swelling in the joint and provide relief that may last from a few months to a year. Therapeutic injections can be given up to three times per year.
After the procedure and the immediate assessment are finished, you will stay in a recovery area for about 30 minutes. You can then return home and resume most of your normal activities. Your doctor may recommend follow-up physical therapy that will provide even more pain relief.
The risks of complications from a sacroiliac joint injection are low, although you may have some bruising and soreness at the injection site. Rarely, patients may develop an infection or experience an allergic reaction to the anesthetic.