Sacroiliac (SI) Joint Injections

A sacroiliac (SI) joint injection or a sacroiliac joint block is a diagnostic or therapeutic procedure that is done to either diagnose or treat low back pain associated with sacroiliac joint dysfunction. Sacroiliac are two joints (one on right and other on left side) lying next to the spine that connects sacrum with hip on both sides. Sacroiliac Joint Dysfunction causes pain and inflammation in this area.

Purpose of sacroiliac joint injection

The sacroiliac joint injection is done with following two goals:

  • Diagnosis of the source of pain or to confirm a suspected diagnosis of sacroiliac joint dysfunction (only anaesthesia is injected)

  • To provide therapeutic pain relief associated with sacroiliac joint dysfunction (anaesthesia along with steroid is injected)

Although most of the cases fulfil both these goals but sometimes individual or separated goal can also be considered like only diagnostic or only therapeutic.

Causes of sacroiliac joint pain

Patients with following conditions may have chronic low back pain or SI joint pain that can respond to SI injection:

  • Gout

  • Rheumatoid arthritis

  • Ankylosing spondylitis

  • Psoriasis

  • Fracture

  • Malignancy

  • Congenital deformity

  • Infection

The Sacroiliac Joint Injection Procedure

The procedure is performed under local anaesthesia and mild sedation in an outpatient setting and patient can go home on the same day. A needle is inserted into the sacroiliac joint under fluoroscopy guidance and then diagnostic and/or therapeutic medication is injected into the joint.

  • For only diagnostic purpose, a local anaesthetic (usually lidocaine or bupivacaine) is injected into the joint to confirm the sacroiliac joint pain. Pain source is confirmed to be the SI joint in cases where the injection provides 70-80 relief to the patient even after performing activities that used to enhance pain.

  • For therapeutic purpose, an anti-inflammatory medication (usually a corticosteroid) along with local anaesthetic is injected into the joint to reduce inflammation and pain within the joint.

The patients who respond positively to therapeutic sacroiliac joint injection can repeat this injection for up to three times per year. This can be clubbed with a physical therapy and rehabilitation program to further reduce pain and return the patient to normal activity levels for extended period of time.