Sacroiliac (SI) joint injections can reduce painful inflammation in the SI joints, which are located at the base of the spine. While these two small joints don’t move much, they perform an important task. That is, these joints are responsible for absorbing the forces generated by the upper body, then balancing and transferring the weight to the hips and legs.

If an SI joint becomes irritated or inflamed, chronic low back pain and other symptoms may result. Because this type of damage cannot always be detected in imaging scans, sacroiliac joint injections may be recommended for diagnostic — as well as therapeutic — purposes.

What does an SI injection involve and when will it take effect?

Using fluoroscopy (X-ray imaging) for guidance, a physician injects a mixture of a local anesthetic and steroid medication into the SI joint that is believed to be causing the patient’s symptoms. If the anesthetic provides immediate (but temporary) relief by numbing the pain, this will help the physician identify the pain source and confirm the diagnosis. Within a few hours, the pain can be expected to return as the anesthetic wears off. Later — usually within a few days to a week — the benefits of the stronger, long-acting steroid medications may become apparent, providing significant symptom improvement over an extended period of time.

Although sacroiliac joint injections are not a cure for SI joint inflammation, they can be very effective for certain individuals. A key advantage of SI injections is that they can make an individual feel comfortable enough to participate in exercise and physical therapy, which can further enhance and extend the benefits of this treatment, sometimes to the point that surgery becomes unnecessary.

Are SI injections a good option for you?

If you’re living with chronic low back pain and have tried other conservative treatments without success, a sacroiliac join injection may be an appropriate next step. You are encouraged to work with an experienced physician who can guide your decision-making and help you make the best treatment choices for you.