Is Your
Lower Back Pain
Caused By

SI Joint Dysfunction?

The sacroiliac (SI) joints may become painfully symptomatic, at which time fusion – such as with iFuse Implant System — may be a treatment option.The sacroiliac (SI) joint is an overlooked but surprisingly common source of pain. Among people who have chronic lower back pain, 15-30% of the cases are caused by SI joint dysfunction.1-4 SI joint dysfunction affects as many as 43% of people reporting lower back pain after a lumbar fusion.5

Common Symptoms of SI Joint Dysfunction

SI joint problems are typically characterized by one or more symptoms:

  • Pain from the lower back through the lower buttocks and upper legs; pain may radiate down the back of one leg.
  • The area directly over the SI joints may be sensitive to touch.
  • Pain that gets worse with certain activities or positions that involve the SI joints, such as sitting on the affected side or getting up from a seated position.

Symptoms may be immediately obvious (acute) following an injury, or may progressively develop and worsen over time (chronic).

If you have lower back pain, it is a good idea to mention SI joint assessment to your doctor. Several diagnostic techniques are now available to determine if the SI joints are the cause of your pain.

Painful Activities

A painful activity of the SI joint is sitting.


A painful activity of the SI joint is going from sitting to standing.

Standing Up

A painful activity of the SI joint is stepping up.

Stepping Up

Why Do the Sacroiliac Joints Become a Source of Pain?

The sacroiliac joints are located at the very bottom of the spine, linking the large triangle-shaped bone (sacrum) at the base of the spine with the iliac bones (pelvis) on each side of the sacrum.

The SI joints serve several essential functions, including:

  • Energy transfer for forces between the legs and torso.
  • Strength and stability to stabilize the pelvis, which serves as the base for torso and lower extremity muscles.
  • Widening of the birth canal during childbirth.

Sacroiliac joints are subject to repetitive stresses every day and may degenerate over time or due to injury.

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Diagnosing SI Joint Problems

Your doctor may perform a variety of tests to determine if your SI joints are causing your symptoms:

  • Physical examination. This includes maneuvers designed to provoke your pain. Several tests are typically performed. If three or more are positive, the SI joint may be the cause of your pain.
  • Diagnostic tests. X-rays, CT scans, or MRIs may be helpful in ruling out other sources of back pain. There are no specific imaging tests that are diagnostic for SI joint pain.
  • SI joint diagnostic injection. The SI joints are injected with a local anesthetic. If your pain decreases significantly, it is likely that an SI joint is the source — or a major contributor — of your lower back pain.

Once the SI joint is confirmed as the cause of your symptoms, treatment can begin.

Your doctor will usually recommend a course of nonsurgical treatments, such as medications, physical therapy, a trial of SI joint belting, and injection therapy.

If you are in severe pain, and nonsurgical treatments do not provide lasting relief, surgery may be considered.

Discover a Minimally Invasive Surgery Option for Sacroiliac Joint Fusion

Today, the iFuse Implant System® is available as a minimally invasive surgery designed to address lower back pain from SI joint dysfunction by stabilizing the SI joints.

The iFuse Implant System is intended for sacroiliac fusion for conditions including sacroiliac joint dysfunction that is a direct result of sacroiliac joint disruption and degenerative sacroiliitis. This includes conditions whose symptoms began during pregnancy or in the peripartum period and have persisted postpartum for more than 6 months. There are potential risks associated with the iFuse Implant System. It may not be appropriate for all patients and all patients may not benefit. For information about the risks, visit:

SI joint treatment using the patented triangular design of the iFuse Implant™, which has been commercially available since 2009, has produced unparalleled clinical results; it is the only SI joint fusion device with clinical studies demonstrating that treatment improved pain, patient function, and quality of life.6-10

iFuse At a Glance

Procedures Performed

iFuse Publications

Active Surgeons

The iFuse Procedure


A 2 to 3 cm incision is made along the side of your buttock.


Real-time images of internal structures are used to guide the surgical instruments.


The surgeon uses instruments to prepare the bone for the implants.


Three small triangular, titanium implants are inserted across the SI joint to stabilize it and allow fusion across the joint.

The iFuse Implant procedure takes approximately one hour. Most patients return home later the same day or after one night in the hospital, but your surgeon will decide when you can return home based on your postsurgical status.

Before going home, you will be instructed on postsurgical care, such as how to care for the incision, and a follow-up visit will be scheduled.

Short animation of SI joint dysfunction and the iFuse surgery

SI Joint Surgery Is a Personal Decision

The iFuse Implant System Patient Experience

Implants used in the iFuse Implants System range in size from 30 to 70 millimeters in length and 4 and 7 millimeters in diameter. iFuse Implants are placed horizontally across the symptomatic SI joint for stabilization and to encourage fusion.Doctors typically advise that you carefully weigh your treatment options.

Here are some questions to ask before deciding on SI joint surgery:

  • Diagnosis for the cause of your pain. Make sure your diagnosis identifies the Si joint as the underlying cause of your pain. This includes a clinical diagnosis that identifies the SI joint as a pain generator due to SI joint disruption or degenerative sacroiliitis.
  • Find an experienced surgeon. Ask your surgeon about the iFuse procedure and its potential benefits and risks. It’s important you feel confident with your surgeon’s experience.
  • Understand the surgery. Do your own research to understand how SI joint fusion works and what to expect before, during, and after the procedure. Reading this page and watching the videos can help you begin determining if iFuse is the right treatment for you.
  • Actively participate in your own recovery. Postsurgical recovery will usually involve some preparation, time off, and physical therapy. Is this something you are willing and able to do?

For more information about the potential outcomes of the iFuse procedure, please visit

More iFuse Patient Stories

Ray describes why she chose the iFuse Implant System.


Deborah explains her experience with the iFuse Implant System.


James explains how receiving SI joint fusion with the iFuse Implant System impacted his day-to-day.


iFuse Implants helped relieve patient Sherri's symptoms.


Richard explains his experience as an iFuse Implant System patient.


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For information about the risks of the iFuse Procedure, visit: