Fusion and Patient-reported Outcomes of Minimally Invasive Sacroiliac Joint Fusion Surgery: A Meta-Analysis

Purpose: We aimed to evaluate the fusion rate after minimally invasive (MIS) sacroiliac joint (SIJ) fusions and compare patient-reported outcomes (PRO) between MIS SIJF and conservative treatment. Additionally, we aimed to compare the SIJ fusion rate between devices. Methods Using PRISMA-P guidelines, we searched electronic databases using the standardized search strategies for publication dates 1/1/2000-7/17/2024. Our primary outcomes were fusion rates after MIS SIJ fusion as evaluated by CT. Our secondary outcomes included Visual analog score-back (VAS) and Oswestry disability index (ODI). We included randomized controlled trials (RCTs), prospective or retrospective comparative or single-cohort studies, and case series with > 10 subjects. We excluded pediatric studies, studies lacking our outcomes, non-degenerative pathology, non-English studies, and those with < 6-month follow-up. Two independent reviewers screened for eligibility and performed a risk of bias assessment using the Cochrane Collaboration Risk of Bias (RoB) tool and the Methodological Index for Non-Randomized Studies (MINORS) tool, and extracted data. A third reviewer arbitrated throughout all stages. Random or mixed-effects models and inverse variance were used for synthesis. Q and I ² statistics were used to assess heterogeneity. GRADE was used to evaluate the quality of evidence used in our recommendation. We used Review Manager and Comprehensive Meta-Analysis. This protocol was registered at PROSPERO: 2021 CRD4202127348. Results One thousand and sixteen studies were identified. Thirty-eight were included after the screening. There were 4 RCTs, 32 single cohorts/case series, and 2 comparative cohort studies totaling 2,847 patients. Fusion outcomes demonstrated a pooled event rate of 0.86 (95% CI 0.78–0.91). Patient-reported outcomes demonstrated a significant improvement after SIJF in pooled mean VAS (-4.90, 95% CI -5.49 to -4.30, p = .00) and ODI (-22.01, 95% CI -27.90 to -16.12, p = .00). Among the comparative cohort studies, the SIJF group demonstrated a significantly improved pooled VAS (-3.71, 95% CI -4.74 to -2.68, p < .00001) and ODI (-19.30, 95% CI -23.87 to -14.4, p = .00001). There was no significant difference in fusion rate between devices and PROs between MINORS subgroups. I ² indicated moderate to significant heterogeneity across all estimates. Per GRADE, the overall quality of the evidence of our recommendation is very low to moderate. Conclusion We demonstrated significant improvement of VAS after SIJF with moderate quality of evidence. We could not make a definitive conclusion regarding fusion rate, ODI, or comparative VAS (SIJF vs. conservative) due to the low quality of evidence. Further research is warranted to strengthen the evidence.