SI Joint Injection

What is an SI Joint Injection?

A Sacroiliac (SI) joint injection is a procedure where a doctor injects medicine into the sacroiliac joint — the joint that connects the lower spine to the pelvis. The injection usually contains a steroid (to reduce inflammation) and a local anesthetic (to numb the area). It can be used to both diagnose whether the SI joint is causing your pain and to treat pain and stiffness in the lower back, buttocks, or legs.

How do you prepare for an SI Joint Injection?

• Tell your doctor about all your medications, especially blood thinners, since you may need to stop them for a short time.
• Discuss allergies or past reactions to steroids, anesthetics, or contrast dye.
• You may be asked to avoid eating or drinking for a few hours before the procedure.
• Wear comfortable clothing.
• Arrange for a ride home, since you may feel numb, weak, or drowsy afterward.

Why is an SI Joint Injection performed?

• To relieve pain and inflammation in the lower back, buttock, or hip caused by sacroiliac joint problems.
• To diagnose if the SI joint is the true source of pain — if the pain goes away after the injection, the joint is likely the problem.
• To help with conditions like arthritis, sacroiliitis.
• To improve mobility and allow participation in physical therapy.

What can you expect during an SI Joint Injection?

• The procedure is usually done in a hospital or ambulatory surgery center and takes about 20–30 minutes.
• You’ll lie on your stomach. The skin over your lower back/hip area is cleaned and numbed.
• The doctor uses X-ray guidance (fluoroscopy) to place the needle accurately into the SI joint.
• A small amount of contrast dye may be used to confirm placement.
• The steroid and numbing medicine are injected.
• You may feel pressure or mild discomfort, but the numbing medicine helps.
• You can go home the same day.

What is the follow-up like for an SI Joint Injection?

• You may feel immediate relief from the numbing medicine, but it can wear off in a few hours.
• The steroid usually starts working in 5-10 days.
• Pain relief may last weeks to several months, depending on your condition.
• Your doctor may recommend physical therapy or exercises to strengthen the area.
• Injections can be repeated if pain returns, but usually no more than 3–4 times a year.

What are the potential risks for an SI Joint Injection?

Most side effects are mild and short-term, such as:

• Soreness or bruising at the injection site.
• Temporary increase in pain before it gets better.
• Feeling weak or numb in the leg for a few hours.

Less common risks include:

• Infection.
• Bleeding.
• Allergic reaction to medicine or dye.
• Nerve injury (very rare).

Are there related tests to an SI Joint Injection?

• X-rays, CT scans, or MRI scans may be done before the injection to look for other causes of back or hip pain.
• A physical exam helps the doctor decide if the SI joint is the likely pain source.