Sacroiliac Joint Pain: Causes, Symptoms, and Fusion Options for Relief

Written by Sukanya Chebrolu, MS and Chukwunonso C. Ilogu, MD, MS of the LESS™ Society.

If you're dealing with persistent lower back pain and nothing seems to help, your sacroiliac (SI) joint could be the missing piece in the puzzle (1). Many patients go through months, even years of treatments without relief, simply because the true source of pain hasn't been correctly identified.

SI joint dysfunction is a common but often overlooked cause of lower back pain. In this blog, we’ll walk you through what the SI joint does, why it can hurt, and how both traditional and newer fusion techniques including Less Exposure Spine Surgery (LESS™) approaches can offer lasting relief. What Is the Sacroiliac (SI) Joint?

The sacroiliac (SI) joints are located on each side of your lower back, where the sacrum (the bottom of your spine) meets the iliac bones (part of your pelvis). These joints support the weight of your upper body and act as shock absorbers during movement. 

Normally, SI joints move just a little but when that movement becomes too much (instability) or too little (stiffness), pain and dysfunction can occur. What Causes SI Joint Pain?

SI joint pain can stem from many factors, including (2):  

• Previous lower back surgery, especially lumbar fusions.

• Pregnancy and childbirth (due to pelvic changes).

• Injury or trauma, such as falls.

• Arthritis or joint degeneration with age.

• Uneven leg length or altered walking patterns.
  

Pain from SI joint dysfunction is usually felt in the lower back, buttocks, or hips, and may radiate down the leg often mimicking sciatica. You may notice it worsening when you stand, walk, or climb stairs for long periods. 

How Is SI Joint Pain Diagnosed and Treated?

SI joint dysfunction can be difficult to pinpoint because its symptoms overlap with other spinal conditions. Diagnosis typically involves:

• A detailed physical exam.

• Imaging studies.

• Diagnostic SI joint injections to confirm the pain source.

Conservative Treatments First 

Before considering surgery, most patients start with conservative treatments to relieve pain and improve function, such as:

• Physical therapy.

• Anti-inflammatory medications.

• SI joint belts to stabilize movement.

• Therapeutic injections.

However, if pain persists despite these efforts, SI joint fusion may be recommended to stabilize the joint and eliminate movement that’s causing pain (3,4,5). SI Joint Fusion: Traditional vs. Modern Approaches

Traditional SI joint fusion was often performed through a posterior approach or a lateral trajectory, where implants were placed across the joint for rigid transfixation. While effective, these methods required open exposure, more soft tissue disruption, and longer recovery times. The LESS™ Society Approach to SI Joint Fusion

At the LESS™ Society, we promote techniques that follow our R.E.P. philosophy: 

• Restore function.

• Ensure early return to mobility.

• Preserve natural anatomy wherever possible.

Our approach to SI joint fusion supports percutaneous (through-the-skin) techniques that minimize muscle disruption and allow for quicker recovery with fewer complications.

An Innovative Example: Sacrix™ SI Fusion System

One such modern approach is the Sacrix™ SI fusion system, designed specifically for percutaneous lateral-oblique access.

What makes Sacrix™ different?

• It avoids violating the joint capsule.

• Uses variable-threaded screws for solid fixation.

• Allows for day surgery with less downtime.

• Preserves soft tissue and avoids traditional open exposure.

Sacrix™ reflects the kind of innovation that aligns with the LESS™ mission: doing less harm, with better outcomes for patients (6).

The image below shows how Sacrix™ is positioned to achieve secure fixation while preserving surrounding structures.

Above: Visual of the Sacrix™ percutaneous lateral-oblique sacroiliac (SI) joint fixation technique, highlighting implant placement across the SI joint with an accompanying X-ray view. This approach stabilizes the joint while minimizing tissue disruption.

Image Source: https://www.mysacrix.com/ Take the Next Step Toward Relief

If you're struggling with chronic lower back or pelvic pain that hasn’t responded to treatment, ask your doctor about the sacroiliac joint. With proper diagnosis and evolving options like LESS™-aligned SI fusion, long-lasting relief is possible. Visit the LESS™ Society to discover how advanced care can help you move with less pain and more confidence.

Frequently Asked Questions (FAQs)

1. How do I know if my SI joint is the real cause of my back pain?

SI joint pain is often misdiagnosed. If your pain is mostly in the buttocks or low back and worsens with standing or climbing stairs, ask your provider about a diagnostic SI joint injection it’s one of the most reliable ways to confirm SI joint dysfunction.

2. Is SI joint fusion a major surgery? 

Not anymore. Newer techniques like the Sacrix™ system allow for less invasive, outpatient procedures that stabilize the joint with less pain, smaller incisions, and faster recovery times.

3. How long does it take to recover from SI joint fusion? 

Most patients begin walking the same day and return to light activity within a few weeks. Full recovery varies, but percutaneous techniques typically offer a smoother and quicker healing process than traditional open surgery. 

REFERENCES

1. Forst SL, Wheeler MT, Fortin JD, Vilensky JA. The sacroiliac joint: anatomy, physiology and clinical significance. Pain Physician 2006;9:61–7. 

2. Dreyfuss P, Dreyer SJ, Cole A, Mayo K. Sacroiliac joint pain. J Am Acad Orthop Surg 2004;12:255–65. https://doi.org/10.5435/00124635-200407000-00006.\ 

3. Chin KR, Spayde E, Costigan WM, Raikar SV, Navalgund YA, Pannozzo P, et al. A prospective multicenter randomized controlled trial on safety and procedural competency in SI joint fusion performed by interventional pain physicians trained by a spine surgeon. Spine J 2025:S1529-9430(25)00243-8. https://doi.org/10.1016/j.spinee.2025.05.014. 

4. Cahueque M, Grajeda J, Ardebol J, Azmitia E. Posterior oblique technique for sacroiliac joint fusion leads to greater pain relief and similar improvement in function compared to the lateral technique: A retrospective, comparative study. N Am Spine Soc J 2023;15:100259. https://doi.org/10.1016/j.xnsj.2023.100259. 

5. Raikar SV, Nilles-Melchert T, Patil AA, Crum W, Pandey D. Posterior Oblique Approach for Sacroiliac Joint Fusion. Cureus 2023;15:e33502. https://doi.org/10.7759/cureus.33502. 

6. Chin KR, Francis RR, Costigan WM, Spayde E, Ike C, Jeong Y, et al. Salvage of failed direct lateral sacroiliac joint fixation using a new percutaneous lateral-oblique transfixation technique with two variable-threaded screws: a multicenter case report of three cases. J Spine Surg 2023;9:348–56. https://doi.org/10.21037/jss-23-43.