Sacroiliac Joint Injection for Lower Back Pain

Sacroiliac (SI) joint injection is a minimally invasive procedure that involves injecting a mixture of local anesthetic and/or corticosteroid medication directly into the SI joint. The SI joint is located in the lower back and connects the sacrum to the ilium bone (part of the pelvis). The injection is performed under x-ray or ultrasound guidance to ensure accuracy and precision.

Goals of SI Joint Injections

SI joint injections are used for one or both of the following purposes:

• Diagnostic purposes: To help confirm whether the SI joint is the source of lower back pain. This injection is typically performed using only a local anesthetic. If the patient experiences significant pain relief immediately after the injection, it’s a strong indicator that their SI joint is likely the source of their pain.
• Treatment: To help provide longer relief from SI joint pain. Depending on the mixture of medications used, the duration of pain relief varies but can last anywhere from several days to months.

When used as a treatment, the goal of this injection is to provide relief from lower back pain caused by SI joint dysfunction, help advance the goals of physical therapy, and improve the patient’s quality of life by improving function in the affected joint.

See Sacroiliac Joint Dysfunction Symptoms and Causes

SI Joint Injections: Types and Uses

Administering a steroid mixture into the joint is a common type of SI joint injection, but there are several other types of injection treatments for SI joint pain, and each type acts through a different mode of action to provide pain relief. 

• Local anesthetic and steroid injections. Local anesthetic and corticosteroid medications are used to reduce inflammation and provide symptom relief to patients with arthritis, inflammatory conditions, and/or acute injuries.
• Prolotherapy injections. Prolotherapy is a type of regenerative therapy that involves injecting a medicated solution into the affected area to induce tissue regeneration, promoting healing and reducing pain.
• Platelet-rich plasma injections. Platelet-rich plasma, or PRP, helps repair damaged cartilage, tendons, ligaments, muscles, or even bone using the patient’s own blood and its natural healing properties.
• Radiofrequency ablation. Radiofrequency ablation (RFA), also called radiofrequency neurotomy, is a procedure that involves heating a part of a pain-transmitting nerve with a radiofrequency needle to create a heat lesion to prevent the nerve from sending signals to the brain. Watch Lumbar Radiofrequency Neurotomy Video

A physician with special training in the treatment of musculoskeletal disorders can help identify the type of injection treatment suitable for the specific underlying condition and symptoms.

Common Conditions Treated with Sacroiliac Joint Injections 

SI joint injections are indicated when the source of lower back pain or leg pain is suspected to originate from the sacroiliac joint.

The SI joint can become painful due to a variety of conditions, including:

• SI joint dysfunction: Pain caused by excessive or insufficient movement of the SI joint. SI joint dysfunction is the most common cause of SI joint pain and typically occurs due to:
  • Injury
  • Pregnancy
  • Osteoarthritis
• Ankylosing spondylitis: Inflammatory arthritis that affects the spine and can lead to SI joint inflammation over time

It is important to note that before considering an SI joint injection for lower back pain, it is necessary to rule out other potential causes and try non-interventional treatments first, such as physical therapy or over-the-counter medications. Patients with chronic lower back pain who have not found relief from other treatments, such as oral medication, physical therapy, or manual manipulation, may benefit from SI joint injections.

See Treatment Options for Sacroiliac Joint Dysfunction