Study type	Author (year)	Groups studied and intervention	Results and findings	Conclusions
Review article	Joukar et al. (2020)[@114113]	55 studies that were reviewed to understand the efficacies of open versus minimally invasive SIJ fixation	Minimally invasive techniques involve less tissue damage, blood loss, and duration of hospitalization, leading to better clinical outcomes	Despite the satisfactory data on clinical outcomes of SIJ fixation surgery, the data on biomechanics of the SIJ in general and fixation techniques, in particular, are sparse.
Multi-center, retrospective comparative cohort study	Smith et al. (2013)[@114121]	149 patients treated with OS and 114 treated with MIS SI joint fusion. Operative measures including surgical operating time, length of hospitalization, and estimated blood loss (EBL) were collected along with demographics and medical history, surgical complications, and 12- and 24-month pain scores. Improvements in pain were compared after matching for age and gender and controlling for a history of lumbar spine fusion using repeated measures analysis of variance.	Compared to OS patients, MIS patients were on average 10 years older (mean age 57 vs. 46) and 69% of all patients were female. MIS operative measures of EBL, operating time, and length of hospitalization were significantly lower than open surgery (p < 0.001). Pain relief, measured as change from baseline to 12 months in VAS pain rating, was 3.5 points lower in the MIS vs. OS group (−6.2 vs. -2.7 points, p < 0.001). When matched for age, gender, and a history of prior lumbar spinal fusion, postoperative pain scores were on average 3.0 points (95% CI 2.1 – 4.0) lower in MIS vs. OS (rANOVA p < 0.001).	In this multi-center comparative study, patients who underwent either OS or MIS SI joint fusion showed postoperative improvements in pain score. Compared to OS patients, patients who underwent MIS SI joint fusion had significantly greater pain relief and more favorable perioperative surgical measures
Review article	Martin et al. (2020)[@114109]	Literature review of studies with the term “sacroiliac joint fusion” that had at least 12 months of clinical follow-up, reported on minimally invasive techniques and included patient-reported outcome measures.	Compared with open fusion, minimally invasive SI joint fusion was associated with shorter operative times (70 versus 163 minutes), lower estimated blood loss (33 versus 288 mL), and lower hospital length of stay (1.3 versus 5.1 days, all comparisons P < .0001) Operative complications occurred in 21% and 18% of the open and minimally invasive groups. At 12 months, pain scores improved by 2.7 points in the open group and 6.2 points in the minimally invasive group. The 2-year pain scores (available in only 96 patients) showed improvement of 2 points in the open group and 5.6 points in the minimally invasive group.	Minimally invasive SI joint fusion provides clinically significant improvement in pain scores and disability in most patients, across multiple studies and implant manufacturers.