Computed Tomography: What Is A Fluoroscopic Guided Sacroiliac Joint Injection?

At the base of the lumbar spine are vertebrae that are fused together and do not move. Called the sacrum, they form a triangular shaped bone that lies between the iliac bones that make up the pelvis. The sacroiliac joints connect the lower spine to the pelvis and are held together by a collection of strong ligaments. Normally, there is very little movement in this joint and, when standing, they support the entire weight of the upper body. Poor posture and improper lifting can lead to increased wear and tear on the cartilage resulting in pain and sacroiliac joint dysfunction.

Fluoroscopic guided sacroiliac joint injections are one treatment option available to reduce or eliminate pain coming from the sacroiliac joint. The procedure is performed on an outpatient basis in the radiology department. Patients should have no solid food or fluids after midnight, on the day before the procedure, unless otherwise directed by their physician.

How Is A Fluoroscopic Guided Injection Performed?

back painMost patients are allowed to take medications with a small amount of water on the morning of the procedure. Diabetics should not take medication until after the procedure is completed, and individuals taking blood thinners must consult with their physician well before the procedure for recommendations to reduce the potential for bleeding. Their physician will discuss the risks and benefits of the procedure prior to the patient signing a consent form.

The procedure is performed in the radiology department with a patient on their stomach. The injection site is cleaned and the area numbed with a local anesthetic. Using the guidance of fluoroscopy a needle is placed into the sacroiliac joint after which medication is injected. Once the needle is removed the area is cleaned again and a small bandage applied.

Sacroiliac joint injections are performed after conservative treatment for pain has been unsuccessful. During the procedure the physician may inject cortisone to reduce the inflammation. This is a powerful anti-inflammatory medication commonly used to control pain and inflammation. Hyaluronic acid has also been used for injection into the SI joint. The effects of these injections are temporary and expected to last several months.

Side effects related to fluoroscopic guided sacroiliac joint injections include bleeding, infection, or an allergic reaction to any of the medications used. Some patients have reported temporary numbness or weakness in the legs from the anesthetic, which often resolves within several hours. Some patients have reported increased pain for several days after the injection and diabetics can experience short-term elevation of blood sugar as a result of steroid medications used.

Fluoroscopy or computed tomography is necessary for accurate placement of sacroiliac joint injections. In one study, researchers found that an accurate placement was achieved in only 12% of patients when fluoroscopy was not used, even when the physician was experienced at performing the procedure. In another study the rate of intra articular injection was 22% without computed tomographic or fluoroscopic guidance. Because computed tomography is time-consuming and expensive, most physicians prefer using fluoroscopy.

Conditions Related To Fluoroscopic Guided Sacroiliac Joint Injections

A painful sacroiliac joint is a common cause of mechanical low back pain. Although it remains unclear why the joint might become painful, theoretically the pain can be related to a hyper- or hypo-mobile joint. In an adult, the joint moves very little. Slight increases or decreases in the mobility of the joint can increase the amount of wear and tear on the cartilage and therefore increase the potential for damage to the joint, causing pain. The sacroiliac joint is a synovial joint, similar to the type of joint at the knee, hip, or shoulder. The joint can be affected by conditions such as rheumatoid arthritis, gout, psoriasis, and osteoarthritis.

Any change in the mobility of the joint can be related to pregnancy, leg length discrepancy, or poor posture increasing the amount of weight load on the sacroiliac joint. The joint can also suffer injury, such as during a fall or an automobile accident. Often, the exact cause of the sacroiliac joint dysfunction may not be identified. The most common types of symptoms are low back pain and pain in the buttocks that affects one or both sides. Some people report pain in the groin area and others muscle spasm in one or both of their buttock muscles. The pain may make sitting difficult.


Sacroiliac joint dysfunction is a common cause of mechanical low back pain. Research has demonstrated that sacroiliac joint injections without the use of imaging techniques have a low success rate ranging between 12% and 22%. Fluoroscopic guided sacroiliac joint injections are one treatment option available for patients who suffer from pain related to sacroiliac joint dysfunction. The procedure is performed in the radiology department using guidance from fluoroscopy or computed tomography. The effect of the injection is temporary and expected to last only several months. Though considered safe, like any procedure, there are possible side effects. A discussion with your pain doctor will help you in determining whether fluoroscopic guided sacroiliac joint injections are a good treatment option for your pain.


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