A precise injection into the SI joint that helps relieve stubborn lower back, hip, and buttock pain caused by joint inflammation or dysfunction.
A sacroiliac (SI) joint injection is a medical procedure where a local anesthetic and corticosteroid is injected into the sacroiliac joint, located at the junction where the sacrum (the triangular bone at the base of the spine) meets the iliac bones of the pelvis. This joint plays a crucial role in absorbing shock and stabilizing the pelvis. When there's inflammation or dysfunction in the SI joint, it can cause pain in the lower back, buttocks, and legs.
The sacroiliac joints are two of the largest joints in your body, and they bear a tremendous amount of stress every day. Walking, standing, sitting, bending, and even rolling over in bed all involve these joints. When one or both SI joints become inflamed or move improperly, the resulting pain can be deep, achy, and persistent. It is often felt on one side of the lower back or buttock, and it can sometimes travel down the back of the thigh, which makes it easy to confuse with sciatica.
An SI joint injection serves two purposes. First, the local anesthetic provides temporary numbing of the joint, which helps confirm whether the SI joint is truly the source of your pain. If you experience significant relief shortly after the injection, that is a strong indicator that the SI joint is the problem. Second, the corticosteroid works over the following days and weeks to reduce inflammation inside the joint, providing longer-lasting relief.
Sacroiliac joint injections are recommended for patients who have pain that appears to originate from the SI joint. You may be a good candidate if you are experiencing:
SI joint dysfunction is particularly common in women, especially after pregnancy or childbirth, due to the hormonal changes and physical stress on the pelvis. It can also develop after lumbar fusion surgery, as the altered mechanics of the spine place additional stress on the SI joints.
The procedure is performed in an outpatient setting and usually takes about 15 to 20 minutes. Here is what to expect:
You will lie face down on a procedure table. The skin over the SI joint area will be cleaned and sterilized, and a local anesthetic will be applied to numb the surface so you stay comfortable.
Using fluoroscopic guidance (live X-ray), your doctor will carefully direct a thin needle into the SI joint. The fluoroscopy allows for precise placement, which is important because the SI joint can be difficult to access due to its location and the surrounding bone structure. A small amount of contrast dye may be injected to confirm that the needle is positioned correctly inside the joint.
Once placement is confirmed, a combination of local anesthetic and corticosteroid is injected into the joint. The anesthetic provides temporary pain relief that may begin within minutes, while the corticosteroid takes several days to reduce inflammation and deliver its full benefit.
The needle is then removed, and a bandage is placed over the injection site. You will be monitored for a short time before you are cleared to go home.
SI joint injections are a commonly covered procedure under most insurance plans, including Medicare, when medical necessity is established. Your actual out-of-pocket expense will depend on your plan's deductible, copay structure, and the facility where the procedure is performed. We will check your insurance benefits ahead of time and let you know what to expect.
Recovery after an SI joint injection is generally quick. Most patients are back to their normal routine within one to two days. Immediately after the procedure, you may notice that the pain in your lower back or buttock feels better due to the local anesthetic. This numbing effect is temporary and will wear off within a few hours. It is not uncommon for pain to return or even feel slightly worse for a day or two before the corticosteroid begins working. For the first 24 to 48 hours, take it easy. Avoid heavy lifting, vigorous exercise, and prolonged sitting. You can apply ice to the injection area for 15 to 20 minutes at a time if there is any soreness. Avoid baths, hot tubs, or swimming pools for at least 24 hours, though showers are fine. The anti-inflammatory effects of the steroid typically begin to develop within three to seven days, with peak relief usually occurring around one to two weeks after the injection.
Results from an SI joint injection vary depending on the severity of the joint dysfunction and your overall health. If the injection provides significant pain relief, it confirms that the SI joint is the source of your symptoms. This diagnostic information is valuable in shaping the rest of your treatment plan. Many patients experience weeks to months of meaningful relief from a single injection.
Some patients may benefit from a second injection if the first one provides partial but not complete relief. Your doctor may also recommend pairing the injection with physical therapy to strengthen the muscles that support the pelvis and improve joint stability, which can extend the benefits of the injection.
For patients who respond well to SI joint injections but find that the relief does not last long enough, other options such as radiofrequency ablation of the nerves around the SI joint may be discussed as a next step.
Here are a few things to keep in mind before your SI joint injection:
Medications: Tell your doctor about everything you are taking, especially blood thinners, aspirin, and anti-inflammatory medications. Some of these may need to be paused before the procedure. Your doctor will provide clear instructions about which medications to stop and when.
Allergies: Let your doctor know if you have any known allergies to anesthetics, corticosteroids, or contrast dye.
Transportation: You will need a driver to take you home. Even without sedation, the injection can temporarily affect how you move and feel.
Diabetes: Corticosteroids can cause a temporary increase in blood sugar levels. If you have diabetes, plan to monitor your levels more frequently for several days after the injection and discuss any concerns with your doctor beforehand.
Activity level: Plan to take it easy the day of the procedure. Light walking is fine, but avoid anything strenuous for at least 24 to 48 hours.
Illness: If you develop a fever or signs of infection before your appointment, contact the office. The procedure may need to be postponed.
Conditions We Commonly Treat With SI Joint Injections
When the sacroiliac joint moves too much or too little, it creates persistent lower back and buttock pain that can mimic sciatica. This injection targets the inflammation directly inside the joint.
Hormonal changes during pregnancy loosen the ligaments around the SI joint. Many women continue to experience pelvic and lower back pain well after delivery, and this injection can provide meaningful relief.
One of the most useful aspects of an SI joint injection is its ability to confirm the source of your pain. If you feel significant relief shortly after the injection, it tells your doctor that the SI joint is the problem, which helps shape the rest of your treatment plan with confidence.
If SI joint injections provide good but short-lived relief, your doctor may recommend radiofrequency ablation as a next step. This procedure uses heat to interrupt the nerve signals coming from the joint, offering months of relief from a single treatment.
