Understanding the Sacroiliac Joint (SI Joint)

Where Is the Sacroiliac Joint?

The sacroiliac (SI) joint connects the last segment of the spine, the sacrum, to the pelvis.  The integrity of the sacroiliac joint SI Jointdepends on strong ligaments that encase and cover the joint.  These ligaments compress and stabilize the joint.


How Does the SI Joint Cause Lower Back Pain?

The ligaments that encase the SI joint may be disrupted due to injury or degenerate due to age, allowing the joint to have excessive motion. This excessive motion may inflame and disrupt the joint and surrounding nerves.

Your physician may also refer to sacroiliac joint pain by other terms like sacroiliitis, SI joint degeneration, SI joint inflammation, SI joint syndrome, SI joint disruption and SI joint strain.

How Do the Symptoms of SI Joint Pain Present?

The most common symptom of sacroiliac joint disorders is pain in the lower back, buttock and legs.  This can present as sciatica like symptoms (leg pain, burning, numbness, and tingling) that mimic lumbar disc or radicular low back pain, pain that radiates down into the legs.


What Is SI Joint Dysfunction?

SI Joint
The most common symptom of SI joint dysfunction is pain in the lower back, buttock and legs.

SI joint dysfunction occurs with structural changes to the joint or changes to the relative positions of the sacrum and pelvis.  Symptoms may start when the SI joint has too much movement (hypermobility) or too little (hypomobility).

If these ligaments are torn, the pelvis can become unstable.  When these ligaments become damaged either due to normal wear and tear or by injury, they may have excessive motion. This excessive motion may inflame and disrupt the joint and surrounding nerves.

Some physicians may also refer to SI joint dysfunction by other terms like sacroiliitis, SI joint inflammation, SI joint syndrome, and SI joint strain.

The most common symptom of SI joint dysfunction is pain in the lower back, buttock and legs.  This can present as sciatica-like symptoms – such as leg pain, burning, numbness and tingling – that mimic discogenic or radicular low back pain.



Click here to watch another video of Dr. Gerlach discussing SI pain

Causes of SI Joint Dysfunction

Causes of SI joint dysfunction can be split into five categories:

  • Traumatic (lifting, fall, accident)
  • Biomechanical (leg length discrepancy, prior lumbar fusion)
  • Hormonal (pregnancy / childbirth)
  • Inflammatory joint disease (sacroiliitis)
  • Degeneration (age related wear and tear)

Diagnosing SI joint Dysfunction 

In order to diagnose SI joint dysfunction, your physician will typically start with a history and a physical examination.  During the physical examination, your physician may try to determine if the sacroiliac joint is the cause of pain through movement of the joint. If the movement recreates the pain, the SI joint may be the cause of the pain.

Your physician may also use X-rays, CT-scan or MRI to help in diagnosing the sacroiliac joint. It is also important to remember that more than one condition (like a disc problem) can co-exist with SI joint dysfunction.

Finally, your physician may request SI joint injections as a diagnostic test.  SI joint injections involve injecting a numbing medication into the SI joint. If the injection alleviates your symptoms, then that means your SI joints are most likely the source of your pain.

Nonsurgical Treatment for SI Joint Dysfunction

Treatments can vary depending on the severity of your symptoms and how much they limit your everyday activities. Below are some of the treatment options you may want to discuss with your doctor, depending on your symptoms.

As a first line of treatment, your doctor may prescribe any one or more of the following:

  • Medications like non-steroidal anti-inflammatory drugs, help relieve pain and reduce inflammation.
  • Physical therapy can help provide strengthening and pelvic stabilization exercises to reduce the movement in the SI joint.
  • SI Belt wraps around the hips to help squeeze the sacroiliac joints together. This supports and stabilizes the pelvis and sacroiliac joints.
  • SI joint injections can reduce inflammation and relieve the pain. The steroid medication injected into the back.
  • Chiropractic treatment


Surgical Treatment of SI Joint Dysfunction

If symptoms persist due to instability, your physician may recommend stabilizing your joint with sacroiliac joint fixation.

Traditional Open Surgery

Traditional sacroiliac joint fixation involves open surgery that may take several hours.  Open surgery typically involves a large incision to access the SI joint, bone removal, and adding bone graft to help the joint heal.  Open surgery usually translates into several days of hospitalization.

Minimally Invasive Procedure

The iFuse Implant System® is a minimally invasive option for patients suffering from SI joint dysfunction.

This special procedure takes about an hour and involves three small titanium implants inserted surgically across the SI joint. The entire procedure is done through a small incision, with no soft tissue stripping and minimal tendon irritation. Patients may leave the hospital the next day after surgery and can usually resume daily living activities within six weeks, depending on how well they are healing and based on physician’s orders.

The iFuse procedure offers several benefits compared to traditional SI joint surgery:

  • Minimal incision size
  • Immediate post-operative stabilization
  • Minimal soft tissue stripping
  • Potential of a quicker recovery


Experiencing SI joint pain and looking for relief? Call and schedule an appointment with our spine team at 303-772-1600.