A sacroiliac joint injection is primarily used to diagnose and treat low back pain and/or sciatica like symptoms associated with sacroiliac joint dysfunction. The sacroiliac joints lie next to the spine and connect the sacrum with the pelvis on both sides. Joint inflammation and/or dysfunction in this area can cause pain.
A diagnostic SI joint injection is used to confirm a suspected diagnosis of sacroiliac joint dysfunction. This is done by numbing the sacroiliac joint with local anesthetic (e.g. lidocaine). The injection is performed under fluoroscopy (x-ray guidance) for accuracy. Once the needle has entered the sacroiliac joint, the numbing medication is then injected into the joint. After the numbing medication is injected, the patient is asked to try and reproduce the pain by performing normally painful activities. If the patient experiences 75-80% pain relief for the normal duration of the anesthetic, a diagnosis of SI joint dysfunction is made.
A therapeutic SI joint injection is done to provide relief of the pain associated with sacroiliac joint dysfunction. The injection is performed using the same technique as a diagnostic SI joint injection, except that anti-inflammatory medication (corticosteroid) is included in the injection to provide pain relief by reducing inflammation within the joint. If the patient experiences prolonged pain relief after a therapeutic sacroiliac joint injection they can begin a physical therapy and rehabilitation program to further reduce pain and return the patient to normal activity levels. It may be repeated up to four times per year, if necessary.