What is the best course of treatment for a patient with chronic lower back pain radiating to the hip, lower abdomen, and groin area, exacerbated by leaning forward, transitioning from sitting to standing, and walking, with partial relief from sitting, and localized to the bilateral sacroiliac joint (SIJ) region?

Treatment of Bilateral Sacroiliac Joint Pain

For this patient with bilateral SIJ pain confirmed by clinical localization, the treatment algorithm should begin with conservative multimodal therapy for 6-12 weeks, followed by diagnostic SI joint injections (dual blocks with >70-80% pain relief required), then cooled radiofrequency ablation of the L5 dorsal ramus and S1-S3 lateral branches if conservative measures fail. 1, 2, 3

Initial Diagnostic Confirmation

Before initiating treatment, confirm the diagnosis with:

• At least 3 positive provocative maneuvers (thigh thrust, FABER test, distraction test, Gaenslen's test, lateral compression) which provides 94% sensitivity and 78% specificity for SI joint pain 2, 3, 4
• Plain radiographs of the SI joints (rated 9/9 "usually appropriate") and pelvis including bilateral hips to exclude concomitant hip pathology 2, 3
• MRI of SI joints without contrast (rated 8/9) if radiographs are negative or equivocal, using fat-suppressed fluid-sensitive sequences (T2-weighted fat-suppressed or STIR) 1, 3

First-Line Conservative Treatment (6-12 weeks)

Conservative management must be attempted first and should include:

• Physical therapy focused on pelvic girdle stabilization exercises specifically targeting the SI joint, addressing underlying posture and gait disturbances 3, 5, 4
• Manual therapy and manipulation to address joint mobility 5, 6, 4
• Pelvic stabilization belt which may provide mechanical support 6, 7
• NSAIDs and activity modification as adjunctive measures 4, 8

Second-Line: Diagnostic and Therapeutic Injections

If conservative treatment fails after 6-12 weeks:

• Dual diagnostic SI joint blocks with local anesthetic only (no corticosteroid initially) are required, with >70-80% concordant pain relief on both occasions confirming the SI joint as the primary pain generator 2, 3
• Single diagnostic blocks are insufficient and reduce diagnostic accuracy 3
• Therapeutic intra-articular corticosteroid injections (rated weakly-for by high-quality guidelines) can provide pain relief for >3 months in some patients and should be attempted before ablative procedures 1, 3, 4
• Consider peri-articular injections in addition to intra-articular, as response rates may reach 100% versus 36% for intra-articular alone when extra-articular pain contributions exist 3

Third-Line: Radiofrequency Ablation

After failed conservative treatment and confirmed diagnosis with dual diagnostic blocks:

• Cooled radiofrequency ablation of the L5 dorsal ramus and S1-S3 (or S4) lateral branches is the evidence-based therapeutic intervention, with two weakly-for recommendations from high-quality guidelines stating this should only be performed after initial diagnosis with SI joint injection/block 1, 3, 4
• Cooled RF demonstrates the strongest evidence among ablation techniques for extensive lesioning 4
• Standard (non-cooled) RF or pulsed RF targeting L5 dorsal ramus and S1-S3 lateral branches may be considered if cooled RF is unavailable (rated 2C+) 5

Important Clinical Caveats

Bilateral presentation requires special consideration:

• The patient's bilateral SIJ pain may require staged procedures (one side at a time) or simultaneous bilateral treatment depending on functional status 4
• Pain radiation to the groin and lower abdomen is consistent with SI joint referral patterns and does not necessarily indicate alternative pathology 5, 7
• Pain aggravated by transitioning from sitting to standing and walking is characteristic of SI joint dysfunction due to increased load transmission through the joint 7

Surgical Fusion: Last Resort Only

SI joint fusion should only be considered if ALL of the following criteria are met:

• ≥3 positive provocative maneuvers 3
• Dual diagnostic blocks with >70-80% concordant pain relief 3
• Radiographic evidence of SI joint degeneration 3
• Documented failure of comprehensive conservative management including physical therapy, therapeutic injections, AND radiofrequency ablation 3, 7
• Lateral transfixing technique is preferred over posterior non-transfixing approaches 3

Common Pitfalls to Avoid

• Do not proceed to ablation without dual diagnostic blocks - single blocks have insufficient diagnostic accuracy 3
• Do not skip conservative treatment - the stepwise approach is essential and supported by all high-quality guidelines 1, 9, 4
• Do not assume unilateral treatment will suffice - bilateral symptoms require bilateral evaluation and may need bilateral intervention 4
• Do not use gadolinium contrast for initial MRI evaluation - it has not been shown to significantly increase diagnostic accuracy and adds cost and risk 1