Minimally invasive sacroiliac joint fusion: Primary endpoint results from the prospective, multicenter STACI study

Background Chronic sacroiliac joint (SIJ) pain is highly debilitating. Minimally invasive SIJ fusion has become a commonly performed surgical treatment for SIJ pain, with level I evidence showing clinically significant improvements in pain, function, and quality of life and a low adverse event rate. Primarily performed by surgeons, this procedure is increasingly being performed by interventional pain management (IPM) physicians. Purpose To evaluate the safety and effectiveness of lateral SIJ fusion performed by IPM physicians, compared with prior studies of similar devices. Study Design Prospective, multicenter, single‐arm clinical trial conducted at 15 U.S. sites. Patient Sample A total of 112 patients with a diagnosis of SIJ pain, who met study eligibility criteria, underwent lateral SIJ fusion. Outcome Measures SIJ pain (numerical rating scale [NRS]), Oswestry Disability Index (ODI), quality of life (Patient‐Reported Outcomes Measurement Information System [PROMIS]‐29), patient satisfaction, and device/procedure‐related adverse events. Methods Medical and surgical history and patient‐reported outcomes were assessed at baseline and follow‐up at 1, 3, 6, 12, and 24 months postoperatively. Primary endpoint is change in SIJ pain from baseline to 6 months; statistical evaluation used a noninferiority approach with a 1‐point noninferiority margin compared to prior studies of a similar device. Secondary endpoints included ODI, NRS, PROMIS‐29, device/procedure‐related adverse events, and evidence of fusion via computed tomography scan at 2 years. Twelve‐ and 24‐month follow‐up data collection is ongoing. Results Mean (SD) participant age was 64 (14) years and 68% female. No serious or device‐related adverse events occurred. At 6 months, mean SIJ pain decreased 5.2 points (95% confidence interval [CI] 4.7–5.7), meeting the study's primary noninferiority endpoint ( p < .001 for noninferiority, p < .001 for change from baseline). A majority (91%) had a ≥2‐point improvement in SIJ pain. ODI improved by 25.8 points (95% CI 22.2–29.4, p < .001 vs. baseline). Conclusion Interim trial results support the safety and effectiveness of lateral SIJ fusion performed by IPM physicians. Clinically significant improvements in pain and disability are commensurate with results from surgeon‐performed randomized trials and published literature. Results should be reproduced in randomized trials.