Sacroiliac (SI) Injections

Sacroiliac Joint Steroid Injection

The sacroiliac joint is in the back of the pelvis, between the sacrum (tailbone) and the ileum, which forms the lateral part of your pelvis. It helps transfer weight from the upper body to the legs. Its movement helps give one a graceful walk. It is vulnerable to injury from actions like stepping into a hole while running or having your foot pressed down on the car brake as hard as you can when you see that someone is about to rear end you. In both these instances, the SI joint is subjected to a shearing force, where the leg and the rest of the body go in opposing directions.

The sacroiliac joint is easily injected. We use local anesthetic, steroids, and, occasionally, Synvisc.

If these injections do not relieve the pain, we can proceed to disrupt the nerve supply to the joint using radiofrequency. Although the nerve supply to the joint is more variable that than of the facet joint, radiofrequency ablation of the SI joint has sufficient success to warrant its use.