Chronic low back pain (CLBP) remains the leading cause of disability globally, affecting millions and posing a significant socioeconomic burden. Yet for a substantial portion of patients, the underlying cause remains misdiagnosed or untreated. According to a newly released consensus statement published in Pain Medicine (2025), sacroiliac joint (SIJ) complex pain is a major but often underappreciated source of chronic axial pain.

The new multispecialty, international consensus guidelines, endorsed by 21 medical societies, offer the most comprehensive, evidence-informed framework yet for diagnosing and managing SIJ complex pain. The guidelines are the result of a methodical two-year collaboration among 30 stakeholder organizations, including the Departments of Defense and Veterans Affairs.

Understanding sacroiliac joint complex pain

The sacroiliac joint complex refers to more than just the joint itself. It comprises both:

• The intra-articular (IA) sacroiliac joint; the synovial portion between the sacrum and iliac bones
• The extra-articular (EA) tissues; particularly ligaments (such as the long dorsal sacroiliac ligament), fascia, and associated nerve branches

Pain can arise from either or both components, which explains why some patients fail to respond to targeted intra-articular treatments alone.

Key findings at a glance

• Prevalence: SIJ complex pain is responsible for 15–30% of chronic axial low back pain cases.
• High-risk populations: Post-lumbar fusion patients are especially vulnerable, with prevalence rates as high as 59%.
• Dorsal ligament pain: Often overlooked, this type of pain is likely just as prevalent as IA pain but remains poorly studied.
• Best diagnostic tool: Controlled diagnostic injections remain the reference standard, though not without limitations.
• Most effective treatment: Sacral lateral branch radiofrequency ablation (SLBRFA) has the strongest supporting evidence among interventions.

Diagnosing SIJ complex pain: A layered approach

• Clinical history and physical exam

Common symptoms include:

• Deep buttock pain, often unilateral
• Pain aggravated by prolonged sitting, rising from a chair, climbing stairs, or transitions in movement
• Referred pain to the groin or posterior thigh

• Provocative testing

Five core provocation tests are commonly used:

• Patrick’s test (FABER)
• Gaenslen’s test
• Thigh thrust (posterior shear)
• Compression test
• Sacral thrust

When three or more of these tests are positive, sensitivity and specificity for SIJ pain improve. 

• Gold standard: diagnostic injections

Diagnostic intra-articular SIJ injections with local anesthetic remain the most accepted standard. A positive response is generally defined as ≥50% pain relief, although some practitioners advocate for ≥75%.

Limitations of this method include:

• Off-target injectate spread to the EA tissues or nerves
• Variable anatomy that complicates joint access
• False-positive results due to sedation or corticosteroid effects

Despite these issues, fluoroscopically guided IA injections are essential to accurately confirm the diagnosis.

• Imaging: limited but helpful in specific cases

Standard imaging techniques like MRI or CT offer limited value in diagnosing mechanical SIJ complex pain. Their role is more supportive, helping to:

• Rule out inflammatory sacroiliitis or structural abnormalities
• Assess joint degeneration in post-fusion patients
• Visualize disruptions after bone grafting procedures

Advanced tools like bone scans or SPECT imaging show promise but are not yet validated for routine use.

Who is at risk?

The guidelines highlight several high-risk groups for SIJ complex pain:

• Post-lumbar fusion patients: Up to 59% show SIJ involvement, particularly after L5–S1 fusions
• Pregnant/postpartum women: Hormonal changes and ligamentous laxity increase SIJ vulnerability
• Athletes: Especially those in contact sports or with asymmetrical loading (e.g., runners, football players)
• Patients with leg length discrepancy, scoliosis, or gait abnormalities

Evidence-based treatment options

Step 1: Conservative care (first-line)

Non-interventional therapies are usually tried first and include:

• Physical therapy focused on core stabilization
• NSAIDs or acetaminophen
• SIJ belts or braces to manage joint hypermobility
• Manual therapy or manipulation
• Activity modification

The evidence is low-quality but commonly extrapolated from general low back pain studies.

Step 2: Injection therapies

Intra-articular steroid injections

• Target inflammation or mechanical joint disruption
• Short-term relief (up to 4 weeks)
• Best used when IA pathology is suspected

Extra-articular injections

• More effective for ligamentous or dorsal SIJ pain
• Slightly stronger evidence for short-term relief vs IA injections

Step 3: Biologic injections

• Prolotherapy (dextrose) and platelet-rich plasma (PRP) may offer relief for 3+ months
• Evidence is limited, inconsistent, and low quality
• Not recommended as first-line therapy

Step 4: Radiofrequency ablation (RFA)

RFA is supported by strong evidence, especially for extra-articular SIJ pain involving the sacral lateral branches (SLBs).

Key points:

• SLBRFA yields ≥6 months of pain relief in responsive patients
• Larger lesions or aggressive lesioning strategies improve outcomes
• Motor stimulation improves safety, but sensory stimulation adds little value
• Anticoagulation usually does not require cessation

How is SLBRFA done?

1. Patient receives sacral lateral branch blocks (SLBBs) as a screening tool
2. If ≥50% pain relief is achieved, RFA is considered
3. Lesions are created via heat or cooled RF probes along S1–S3 nerve pathways

Step 5: Minimally invasive SIJ fusion

SIJ fusion is considered only when all other treatments fail. Candidates should have:

• Documented IA pain (based on controlled diagnostic blocks)
• Pain relief with diagnostic injection (typically ≥50%)
• Functional disability impacting daily activities

Evidence rating: Weak to very weak

Despite this, many patients report significant improvement in quality of life post-fusion. The procedure may involve lateral transfixation devices or posterior interpositional implants.

Special case: sacroiliac pain after lumbar fusion

Spinal fusion alters load transmission, often increasing SIJ stress:

• L5–S1 fusion increases SIJ motion by up to 52%
• Fusion to the sacrum raises the risk of SIJ degeneration, especially if iliac crest bone grafts disrupt ligaments or the joint capsule

Studies show:

• 33–59% of post-fusion patients have SIJ complex pain
  
• SIJ injections are positive in ~40–60% of these individuals

Summary of guideline recommendations

• Supported
  • Use of SLBRFA for EA SIJ pain
  • Controlled IA diagnostic blocks
  • Stepwise conservative management
• Controversial
  • Whether 50% or 75% relief from blocks is sufficient for RFA/fusion eligibility
  • The strength of evidence supporting EA vs IA injections

• Not endorsed
  • Routine imaging for mechanical SIJ pain
  • Uncontrolled or non-fluoroscopic injections

Looking forward

This landmark consensus document provides a much-needed foundation for clinicians treating SIJ complex pain. It emphasizes a diagnostic continuum, targeted interventions, and a personalized approach to care.

Priorities for future research:

• Higher-quality RCTs comparing IA vs EA techniques
• Long-term outcomes of SLBRFA and fusion
• Better tools to differentiate dorsal ligament pain
• Standardization of block thresholds and success criteria

Final thoughts

SIJ complex pain is no longer a fringe diagnosis—it is a well-defined, treatable cause of chronic low back pain. With the 2025 consensus guidelines, clinicians now have an actionable roadmap to improve outcomes and reduce suffering for millions of patients.

For more information, refer to the full article in Pain Medicine.

McCormick ZL, Hurley RW, Anitescu M, et al. Consensus practice guidelines on sacroiliac joint complex pain from a multispecialty, international working group. Reg Anesth Pain Med. Published online November 29, 2025.

For more information about sacroiliac joint injections, get the Ultrasound-Guided Interventional Pain Procedures Manual on NYSORA 360!