Sacroiliac Joint Injection Vs. Epidural Injection: What’s The Difference?

Chronic back pain is an all-too-familiar condition and one of the most frequent complaints of many adults and seniors. In fact, studies suggest that over 65 million Americans had a recent episode of severe back pain that caused work-loss days and work limitations. 

Doctors treat chronic back pain by first identifying the underlying disease that’s causing it. But the condition can still be managed using several treatments, such as sacroiliac joint injection and epidural injection.

Pain management specialists, like Dr. Stewart from Advanced Pain Medical Center, use these two techniques to relieve back pain and improve the patient’s quality of life. Although epidural and sacroiliac joint injections both address pain, these two have stark differences when it comes to their target body area and disease.

What is a sacroiliac joint injection?

A sacroiliac joint (SI) injection refers to a technique used to diagnose and treat back pain originating from the sacroiliac joint. The SI joint can be found in the lower back just above and either side of your tailbone, where it connects the sacrum to the pelvis. Its main function is to act as a shock absorber that helps distribute the forces between the upper body and the lower extremities.

Degenerative diseases or injuries cause inflammation and cartilage degeneration in the SI joints, resulting in pain in the buttocks, hips, and lower back. In many cases, sacroiliac dysfunction can also cause pain in the back of the thighs.

Physicians perform sacroiliac joint injections to alleviate pain caused by sacroiliac disorders. 

How is it performed?

Sacroiliac joint injections have two purposes: diagnosing and treating an SI joint condition. Here’s how doctors perform it based on its use:

Diagnostic technique

During a diagnostic SI joint injection, your physician will inject a local anesthetic directly into the SI joint under the guidance of fluoroscopy.  Doctors inject contrast first to ensure proper needle placement before injecting the anesthetic. 

After injecting, if the pain you feel in your lower back eases, then you most likely have a sacroiliac joint condition. Your doctor may perform another round of this diagnostic technique, but this time using a different numbing medication to confirm the SI joint disease diagnosis.

Therapeutic (pain relief)

The same procedure is followed in performing an SI joint injection for therapeutic purposes. But here, your doctor will inject the numbing medication together with an anti-inflammatory medicine (steroid) to reduce pain and inflammation in the area.

Neither technique requires sedation or general anesthesia.

What is an epidural injection?

An epidural steroid injection (ESI) treats specific spinal conditions that cause pain from the neck to the lower back. It is also used to treat conditions that cause pain emanating from the nerve roots, which can radiate from the lower back to the hips, buttocks, and legs. 

Epidural injections help relieve pain and nerve inflammation caused by specific spinal disorders, such as

  • Herniated discs – a bulging in the spinal disc that can cause pain.
  • Cervical or lumbar spinal stenosis – narrowing of the spinal canal that results in the pinching of the spinal nerves. 
  • Post-laminectomy syndrome – pain that persists following back surgery

Doctors administer ESIs into the epidural space一an area in the spine between the spinal cord and the vertebral membrane that protects it.  This is the same space into which numbing medicine is injected for pain relief in a pregnant woman delivering her baby.

How is it performed?

An epidural injection starts with your doctor administering a local anesthetic to the injection site. With the help of x-ray fluoroscopy, the needle will be inserted into the epidural space, wherein the pain-relieving medication is gradually injected. The medicine used is a combination of anesthetic (painkiller) and corticosteroid (anti-inflammatory).  Contrast is also used to confirm proper placement of the needle and fluid.

What are their differences?

Here’s a quick guide on the differences between sacroiliac joint injection and epidural steroid injection.


Sacroiliac joint injection Epidural steroid injection
What is it for? To treat and diagnose arthritic conditions affecting the sacroiliac joints, which cause lower back pain. Used to treat pain originating from the spinal cord or nerve roots, which causes lower back pain that branches into the lower extremities.
Where is it administered? Injected directly into the affected SI joints.  Injected into the epidural space near the affected nerves. 


Patients can go back to their doctor for additional treatment or undergo another sacroiliac joint or epidural injection.

When to seek the best pain management doctor in Gainesville?

If you have been trying different medications and therapy but still haven’t found relief for your back pain, you should consult with Dr. Stewart of Advanced Pain Medical Center.

Dr. Stewart has provided safe and effective pain management treatment plans to his patients for years now. He and his team strive hard to bring long-lasting relief to the source of your pain with high-quality patient care and services. 

Besides several procedures for pain management in Gainesville, our facility also provides other treatment services, such as

Contact us now so we can start creating a treatment plan that meets your needs and can improve your quality of life!


The material contained on this site is for informational purposes only and DOES NOT CONSTITUTE THE PROVIDING OF MEDICAL ADVICE, and is not intended to be a substitute for independent professional medical judgment, advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare providers with any questions or concerns you may have regarding your health.

Advanced Pain Medical Center

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