SI-Bone announces three publications on iFuse use for minimally invasive sacroiliac joint fusion


SI-Bone has announced the publication of one-year results from two separate prospective multicentre clinical trials as well as the publication of a systematic review of 18 minimally invasive sacroiliac joint fusion studies.

“Collectively, these three recent publications significantly strengthen the more than 20 clinical papers already published on iFuse and further solidify our clinical evidence foundation supporting minimally invasive sacroiliac joint surgery using SI-Bone’s unique triangular implants,” said Jeffrey Dunn, president and chief executive officer of SI-Bone.

The first clinical trial publication is of INSITE (Investigation of sacroiliac fusion treatment), a prospective multicentre randomised controlled trial that included 148 subjects treated at 19 centres. One-year results from INSITE were published in the journal Neurosurgery. Subjects were randomised in a 2:1 ratio to either immediate sacroiliac joint fusion with iFuse (102 subjects) or non-surgical management (46 subjects).

Subjects surgically treated with iFuse had a mean 52-point reduction in sacroiliac joint pain at six months on the Visual Analog Scale (VAS) versus only a mean 12.2-point decrease in the non-surgical group. Pain relief was sustained at twelve months in the surgical group with a mean 54.2-point reduction from the baseline VAS measurement. The study design allowed subjects in the nonsurgical group to cross over and have surgery after six months, 79.5% of whom elected to have the iFuse procedure as of June 2015. Non-surgical subjects who elected to cross over to iFuse surgery after six months had pain reduction similar to that seen in subjects originally assigned to iFuse surgery (Figure 1).

The study also used the Oswestry Disability Index (ODI), with a score of 0 indicating no disability and scores >60 indicating severe disability. At baseline, all subjects showed a high degree of disability (mean 56.8). Subjects assigned to iFuse had a mean 27.4-point reduction in ODI at six months while subjects assigned to non-surgical treatment had only a mean 4.6-point decrease (p

At twelve months, taking into account responses due solely to the assigned treatment, clinically important improvements in VAS sacroiliac joint pain were seen in 81.6% of fusion subjects but only 12.5% of non-surgical subjects (p

“Surgery vs non-surgery studies are difficult to execute. INSITE’s design and execution in preventing early crossover has provided significant, high quality, Level 1 evidence to the existing body of literature demonstrating that, for patients with certain sacroiliac joint disorders, fusion with triangular porous coated titanium implants can meaningfully improve pain, function and quality of life compared to non-surgical management,” commented David Polly, lead author of the paper.  “This study shows that significant improvements in pain, disability and quality of life achieved at six months were sustained at twelve months and that subjects who crossed over to iFuse treatment did nearly as well as those originally assigned to iFuse.”

SI-Bone also announced the publication of one-year results from a second multicentre clinical trial of minimally invasive sacroiliac joint fusion. This study—SIFI (Sacroiliac joint fusion with iFuse implant system)—is a prospective multicentre single-arm clinical trial of sacroiliac I joint fusion using iFuse in a patient population with the same enrolment criteria as INSITE. The study included 172 subjects at 26 US centres and was published in Global Spine Journal.

Twelve-month postoperative follow-up was available in 157 of 172 initially enrolled subjects (91%). By six months, 81% of subjects met the study’s definition for treatment success; by twelve months, the success rate was 80%. Mean sacroiliac joint pain improved from 79.8 at baseline to 30 and 30.4 at six and twelve months respectively (mean improvements of 49.9 and 49.1 points, p

“The one-year results from the SIFI study have shown durable improvements in pain, disability, and quality of life with the iFuse procedure. This paper adds important, high quality clinical evidence to the more than two-dozen existing publications that support the safety and effectiveness of the iFuse procedure,” said Brad Duhon, lead author of the SIFI one-year publication.

Si-Bone states that these one-year results from both INSITE and SIFI “demonstrate early and marked improvements in pain, disability and quality of life that were maintained to twelve months in more than 250 subjects.”

The third publication was published in the International Journal of Spine Surgery. Study authors used PRISMA, a published standard for systematic reviews, to perform a systematic review and meta-analysis of published literature reporting clinical outcomes on subjects who underwent minimally invasive sacroiliac joint fusion using a lateral transarticular approach. A total of 18 articles met the inclusion criteria and after accounting for overlapping cohorts, 12 unique cohorts from four countries were extracted for a total of 432 subjects. Of the 12 unique cohorts, 10 were iFuse cohorts that included a total of 368 treated subjects. For the 12 unique cohorts, random effects meta-analysis mean procedure time was 59 minutes (with a range of 27–78 minutes), estimated blood loss was 36.9cc (range of 10–70cc) and hospital length of stay was 1.7 days (range of 0–7 days). The mean pain score dropped by 5.2 points at six months and 5.3 points at 12 months (baseline score of 8.1, 12-month score of 2.7), and a 24-month score of 2. ODI decreased by 31 points at 12 months (baseline score of 56.2, six-month score of 30.7, and 12-month score of 25.1). Two studies in the review had long-term (4.5 and 5 years) follow-up with consistent results.

These results demonstrate that minimally invasive sacroiliac fusion using a lateral transarticular approach provides consistent and clinically important improvements in pain and associated disability that is maintained out to five years. Changes seen in the iFuse cohorts (which represented 85% of treated subjects) were larger than those seen in the cohorts in which hollow modular anchor screws were used. Furthermore, the minimally invasive characteristics of this procedure were confirmed as evidenced by minimal blood loss, a short operative time and brief length of stay.

Clinical publications have identified the sacroiliac joint as a pain generator in 15–30% of low back pain patients. In addition, the prevalence of sacroiliac joint pain in post-lumbar fusion has been shown to be up to 43%. Of these patients with sacroiliac joint pain, some may have degenerative sacroiliitis or sacroiliac joint disruptions. Initial treatment options for patients with sacroiliac joint disorders typically involve non-surgical management and, when non-surgical management of the joint fails, surgical options such as the iFuse procedure may be considered.