A Retrospective, Multicenter Analysis of a Novel Sacroiliac Joint Fusion Device on Safety and Efficacy at 12 Months: Access Study

<b>Introduction</b>: Arthrodesis of the sacroiliac joint (SIJ) has evolved over the last 5 years, with many trajectory strategies emerging. Innovation has outpaced data generation on the safety and efficacy of novel SIJ arthrodesis techniques. This retrospective review of the use of a SiLO TFX SIJ fusion system provides 12-month post-implant outcome data that can be compared with other techniques from published literature. <b>Methods</b>: A retrospective analysis was performed on patients that underwent the SiLO TFX sacroiliac joint fusion procedure at eight sites with data on pain reduction and functional improvement from baseline, as measured by a numerical rating scale (NRS) and Oswestry Disability Index (ODI), along with some safety and device integrity assessments recorded at 12 months post-implant. Safety was assessed by identifying key serious adverse events (bleeding, infection, nerve injury), and device integrity was assessed by evaluating misplaced or malfunctioned devices. ODI and NRS outcomes were compared with published rates from the literature. <b>Results</b>: Between 16 March 2023 and 20 February 2024, 42 subjects with 12-month ODI data available were enrolled. The subjects had a mean age of 60 ± 11 years, and 71% were female. The mean ODI score of 33 ± 15 at baseline improved to 17 ± 11 at 12 months, with a statistically significant improvement from baseline of 16 ± 15 (<i>p</i> < 0.0001). Furthermore, 52% of subjects had a 15-point absolute ODI improvement. Mean NRS of 7.1 ± 2.8 at baseline improved to 2.9 ± 2.2 at 12 months with a statistically significant reduction in pain of 4.2 ± 3.4 (<i>p</i> < 0.0001). No key serious adverse events or device integrity complications were noted. Subgroup analyses for a cohort of subjects with baseline ODI ≥ 30 and VAS pain ≥ 50 demonstrated that performance was similar to that in previously published literature with a mean improvement in ODI of 23.3 ± 12.7 (<i>p</i> < 0.0001) with 78% of subjects achieving a 15-point improvement at 12 months, and mean NRS improving by 4.7 ± 3.0 (<i>p</i> < 0.0001) with 88.9% achieving an improvement of 2 points. <b>Conclusions</b>: This data supports the safety and efficacy of SiLO TFX for SIJ fusion. The retrospective outcomes are comparable to those published for lateral-approach SIJ fusion. As follow up is limited to 12 months in this retrospective dataset; long-term fusion and cost-effectiveness remain to be addressed. Prospective, randomized controlled trials with a larger cohort are needed further to compare SiLO TFX to other available SIJ fusion techniques.