Sacroiliac Joint Block

A sacroiliac joint injection serves several purposes. First, by placing numbing medicine into the joint, the amount of immediate pain relief you experience will help confirm or deny the joint as a source of your pain. That is, if you obtain complete relief of your main pain while the joint is numb it means this joint is more likely than not your pain source. Furthermore, time-release cortisone will be injected into the joint to reduce any presumed inflammation, which on many occasions can provide long-term pain relief (see figure below).

Sacroiliac (SI) joint injections are commonly used to determine what is causing back pain. SI joint injections are primarily diagnostic injections, meaning that they help your doctor determine the cause of your back pain but may not provide you with any long-term relief from the pain. These injections eliminate pain temporarily by filling the SI joint with an anesthetic medication that numbs the joint, the ligaments, and joint capsule around the SI joint. If the SI joint is injected and your pain goes away for several hours, then it is very likely that the joint is causing your pain. Once you and your doctor know what structure is causing your pain, you can begin to explore options for treating the condition.