Conventional vs Bipolar SIJ RFA for Treatment of Sacroiliac Joint Pain

Specific Aims The sacroiliac joint complex (SIJC) is a diathrodial, synovial joint and posterior ligamentous network that receives both anterior innervation from the lumbosacral plexus as well as posterior sensory innervation via the posterior sacral network (PSN). The PSN is comprised by the lateral branches S1-S3 posterior rami, with variable contributions from S4 lateral branch, L4 medial branch, and L5 dorsal ramus. Pain signals originating from the SIJC can be interrupted with image-guided percutaneous radiofrequency ablation (RFA) of the PSN, thereby reducing pain and disability in carefully selected patients. A prior systematic review estimated that 32-89% of patients achieve at least 50% pain relief for six months after some type of PSN ablation. Many experts suspect that heterogenous RFA techniques and technology are responsible for the variable success rates seen across published studies. Cadaveric work suggests that targeting the PSN with a large bipolar strip lesions would result in \>95% PSN neural capture compared to a smaller lesion produced by a conventional, monopolar, periforaminal RFA technique which may capture as low as 2.5% of the PSN. Nimbus is a commonly used multi-tined RFA probe whose large bipolar lesion size make it an ideal option for complete PSN neural ablation. Both the Nimbus (N-SIJRFA) and conventional (C-SIJRFA) techniques and technologies are commonly used; however, there are no prospective RCT's comparing them, and the clinical significance remains unknown. Problem: There are no randomized controlled trials comparing novel technologies like N-SIJRFA to C-SIJRFA. Purpose: To compare pain and disability outcomes in patients with confirmed SIJC pain after randomization to either N-SIJRFA or C-SIJRFA. Central Hypothesis: N-SIJRFA will be more effective in improving pain and function compared to patients treated with C-SIJRFA at 3, 6, 12, 18, and 24 months. Specific Aims: 1. Compare the proportion of participants who report ≥50%