What is a SI Joint Injection?
Sacroiliac (SI) joint injection is a minimally invasive procedure that involves injecting anesthetic and/or corticosteroid directly into the SI joint, located in the lower back. The SI joint connects the sacrum to a part of the pelvis called the ilium bone. SI joint injections are used for the following:
- Diagnostic – to confirm whether the SI joint is the source of the lower back pain.
- Treatment – to help provide relief from SI joint pain.
Causes for an SI Joint Injection
If your provider suspects your lower back pain is caused by the sacroiliac joint, also known as sacroiliitis, an SI joint injection may be needed. The SI joint can become painful due to a few reasons:
- SI joint dysfunction – pain that is caused by excessive or insufficient movement of the SI joint. This commonly occurs due to things like injury, pregnancy, or osteoarthritis.
- Ankylosing spondylitis – inflammatory arthritis that affects the spine and can lead to SI joint inflammation.
Pain your lower back is the most common symptom of sacroiliitis. The pain may:
- Get worse after sitting or standing in one position for a long time.
- Get worse when you turn or rotate your hips.
- Feel suddenly sharp or stabbing.
- Radiate from y our low back to your buttocks, hips or thighs.
Stiffness is common among people with sacroiliitis, especially after sleeping or sitting in one position.
Diagnosis and Treatment for SI Joint Injections
Your healthcare provider will perform a physical examination to confirm the pain’s location and check for signs of infection. They will also review your medical history to ensure there are no interfering conditions. Other imaging test may be needed for a better look at the SI joint and surrounding structures. Prior to the procedure, you may be instructed to stop taking certain medications, like blood-thinners.
SI joint infections are performed outpatient and usually takes anywhere from 15 to 30 minutes. After lying on your stomach, your provider will use an anesthetic to numb the area over your SI joint. Using a fluoroscope, they will insert a thin needle into the SI joint and inject a contrast to ensure the needle is positioned in the joint. The medication will then be inserted into the joint.
What to Expect from an SI Joint Injection
Following the procedure, it is normal to feel pain at the injection site for a few hours. The injection medication will take effect within a few days, reducing inflammation and pain. Your provider may prescribe medication to help assist with the pain in the meantime.
There are no major activity limitations following an SI joint injection. Follow your activity tolerance level and any instructions your provider may give you.
The success rate of an SI joint injection will vary depending on the primary cause of your pain, as well as duration and severity of symptoms. In general, studies have shown that SI joint injections may provide significant pain relief for at least 1 month in those who experience SI joint pain. Some patients may require more than one injection to feel long-term improvement in pain and function. In general, if the first injection is successful in providing pain relief, additional injections may be recommended with no more than 3 injections given per year.
In the first 1-3 months following injection, many patients experience significant pain relief and can return to daily activities as tolerated.
After 6 months, the effectiveness of the injection may begin to diminish, and patients may notice a return of their original pain.
After 1 year, the effectiveness of the injection will likely have worn off although some patients may still feel benefits. Patients should talk with their healthcare provider to discuss the possibility of receiving another injection or exploring alternative treatment options.
Your provider may recommend other treatments to accompany the injection, such as physical therapy, medication, and heat and cold therapy. Your provider will discuss these treatments to determine which is the best to treat the underlying cause of your SI joint pain.
Risks and Side Effects of SI Joint Injections
As with any procedure, there are certain side effects and risks associated with SI joint injections. Although minor and temporary, common side effects may include:
- Pain at the injection site.
- Leg numbness or weakness.
- Increased lower back pain.
While serious complications can occur, they are rare:
- Nerve damage
- Infection
- Allergic reaction to the injection
- Bleeding or bruising at injection site.