Sacroiliac (SI) Joint Injection

SI Joint PainA sacroiliac (SI) joint injection involves injecting a corticosteroid medication with or without a local anesthetic into the SI joint. The SI joints are located on both sides of the sacrum (tailbone), and these joints connect the pelvis and tailbone.

What is the purpose of a SI injection?

The SI injection involves instillation of a steroid, which reduces swelling and inflammation of tissue in and around the joint space. This reduces pain and other symptoms related to the irritation and inflammation of the joint and the structures around it.

Will the sacroiliac joint injection hurt?

The SI joint injection involves the insertion of a very small needle through the skin and deeper tissues, so there is some mild pain. Because most doctors mix a local anesthetic in with the steroid medication, the injection is not as painful.

The patient will experience a burning sensation, however. If necessary, the doctor will provide sedation that makes the procedure easy to tolerate.

How is the sacroiliac injection performed?

The SI joint injection procedure is performed with the patient lying on his or her stomach. Before insertion of the needle, the patient is connected to monitoring devices to assess heart rhythm, blood pressure, and oxygen levels.

The skin on the lower back is cleansed with an antiseptic, and then numbed using a tiny needle andSI Joint Injection use this local anesthetic. Using x-ray guidance, the doctor inserts the needle near the SI joint.

Once the needle is properly positioned, the medication is injected. After the injection, the doctor removes the needle and a dry, sterile dressing is applied to the site.

What should I expect after the sacroiliac injection?

After the SI injection, you will notice that your pain is gone or greatly reduced. This is partly related to the local anesthetic that was injected, and the numbing effect will last for a few hours.

The pain may gradually return, and you will experience mild soreness at the injection site for 24 to 48 hours. By the third or fourth day, you will notice significant pain relief, as it takes this time for the steroid to start working. Be sure to bring someone to drive you home, as you are not permitted to drive after receiving sedation.

What activities can I perform following the SI joint injection?

You are advised to take it easy following the SI injection because it may cause temporary weakness if the medication spreads to the sciatic nerve, which lies in front of the joint and runs down the leg.

For pain and soreness at the injection site, we advise that you apply ice in 20-minute intervals several times each day. Immediately after the injection, only perform those activities that are necessary. However, you can return to your regular duties and activities the day after the procedure.

How many SI joint injections will I need to have?

If the first injection does not improve your symptoms in two weeks, the doctor may recommend that you have one more treatment. If you respond to these SI joint injections, but still experience residual pain, the doctor may recommend a third injection. In a six-month period, you may only be permitted to receive three injections total. Your doctor will determine the total amount of injections in any given time frame.

SI Joint Radiofrequency

SI Joint Radiofrequency

What are the risks and complications associated with the SI joint injection?

The sacroiliac joint injection is a safe, effective procedure. However, as with any minimally invasive procedure, there are a few risks associated with this treatment. The most common side effect is soreness of the injection site.

Rare complications include bleeding, infection, worsening of symptoms, and leg weakness. Side effects to the steroid include water retention, elevated blood glucose levels, and weight gain.

Do SI joint injections work?

According to experts, up to two-thirds of patients have significant improvement of pain and functional ability following an SI joint injection, which typically last for around 9 months. If the pain reoccurs, a repeat injection may be necessary, however.


Hawkins J, Schofferman J. Serial therapeutic sacroiliac joint injections: a practice audit. Pain Med. Jul-Aug 2009;10(5):850-3.

Liliang PC, Lu K, Weng HC, Liang CL, Tsai YD, Chen HJ. The therapeutic efficacy of sacroiliac joint blocks with triamcinolone acetonide in the treatment of sacroiliac joint dysfunction without spondyloarthropathy. Spine (Phila Pa 1976). Apr 20 2009;34(9):896-900.