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.