Sacroiliac joint pain reduction and radiographic evidence of SIJ fusion will be collected to evaluate clinical performance of the SImmetry Sacroiliac Joint Fusion System.

This is a prospective, non-randomized post market study designed to evaluate fusion and pain reduction following the use of the SImmetry System. This study will be conducted at up to 40 sites and 250 total subjects will be enrolled and followed through 24 months. Data will be collected pre-operatively, implant, and at specified follow-up time points through 24 months.

Key Inclusion Criteria:

• At least three positive provocative tests for SIJ pain
• Non-operative management of SIJ pain for ≥ 6 months prior to surgery
• At least one positive diagnostic SIJ injection resulting in a ≥ 50% decrease in pain
• VAS back pain score of ≥ 60 mm
• The subject is at least 18 years of age

Key Exclusion Criteria:

• Trauma causing fracture of the sacrum or iliac bones or has had spinal trauma leading to a neurological deficit, or pelvic soft tissue or bony tumors
• Pregnant or is planning on becoming pregnant in the next two years
• Chemical dependency abuse problems as evidenced by a history of abusing drugs which is documented in their past medical history or is elicited from an interview.
• Receiving or seeking worker's compensation, disability remuneration, and/or involved in litigation related to low back or SIJ pain
• History of significant emotional or psychosocial disturbance

Patients will be recruited from the Investigator's standard patient population diagnosed with SIJ pain and representing candidates for SIJ fusion.