Relieve pain with an SI Joint Injection.

Located in the pelvis, the sacroiliac (SI) joint is responsible for easing the burden of the shift between upper and body weight as you move. If it’s suspected that this joint is the source of your lower back or radiating thigh or leg pain, sometimes referred to as sacroiliitis, you may benefit from a sacroiliac joint injection.

  • The injection can be therapeutic or used for diagnostic purposes.


SI Joint Injections to Determine a Pain Source

For diagnostic purposes, an SI joint injection may be administered to determine if pain in the buttocks, thighs, or legs is due to sacroiliac joint dysfunction, a condition with symptoms similar to sciatica that may be caused by inflammation, pregnancy, or degenerative joint disease (osteoarthritis).

When used to diagnose a source of pain, the injection includes short-acting numbing medication. If 75-80 percent relief of symptoms is experienced after the injection, a tentative diagnosis of SI joint dysfunction is made. A second injection may be given to see if a similar reaction is experienced to further confirm a diagnosis.

A lateral branch block may also be performed to target smaller nerves that control muscle in the mid and lower back. The purpose of this type of block, also administered as an injection, is to determine if a patient may benefit from a minimally invasive pain management procedure referred to as a radiofrequency nerve ablation.


Managing Pain with Sacroiliac (SI) Joint Injections

For therapeutic purposes, an SI joint injection is combined with an anti-inflammatory medication, usually a corticosteroid, to reduce swelling around the affected joint and nearby nerves. It typically takes a few weeks for the full effects of the injection to become apparent. Injections can safely be repeated up to three times per year.

Before, During, and After an SI Joint Injection

Patients often undergo a thorough exam to determine if the SI joint is a possible source of pain. Performed on a table as the patient lies on their stomach, the procedure may involve an IV, especially for patients who need some assistance to relax. It’s not a procedure recommended for patients who are excessively anxious about needles. Numbing medications do, however, ease discomfort from the insertion of the needle.

Special dye is injected to ensure correct placement of the needle. The doctor will use x-ray guidance to reach the right part of the joint. After the needle is in the correct position, numbing medication (for diagnostic purposes) or an appropriate anti-inflammatory medication will be injected. Patients are usually observed for a short period after receiving an injection. Strenuous activities should be avoided for a few days after the injection is given.

Pain related to the sacroiliac joint is sometimes mistaken for sciatic nerve pain since the SI joint is in close proximity of this large nerve. In some cases, irritation of the SI joint can aggravate the sciatic nerve. Injections may provide relief for several months at a time or allow you to actively participate in muscle strengthening exercises that may also minimize your discomfort.