SI-BONE, a Silicon Valley-based medical device company dedicated to solving musculoskeletal disorders of the sacro-pelvic anatomy, today announced the publication of 5-year results from a long-term prospective study called LOIS (Long Term Outcomes from INSITE and SIFI).

The publication, titled Long-term prospective clinical and radiographic outcomes after minimally invasive lateral transiliac sacroiliac joint fusion using triangular titanium implants1 reports 5-year outcomes from a subset of patients who participated in INSITE (Investigation of Sacroiliac Fusion Treatment)2, a U.S. randomized controlled trial and SIFI (Sacroiliac Joint Fusion with iFuse Implant System)3, a prospective multicenter trial.

The LOIS study included 103 subjects treated at 12 centers who were diagnosed with sacroiliac (SI) joint dysfunction and underwent SI joint fusion with the iFuse Implant in either of the two feeder studies (INSITE and SIFI).  Study subjects were evaluated at study start (approximately 2 years after surgery) and again at 3, 4 and 5 years postoperatively.  5-year follow-up was obtained for 93 study subjects (90%) with no loss to follow-up between year 3 to 5.  Mean SI joint pain scores decreased 54 points from baseline prior to surgery with iFuse (0–100 point scale).  Disability scores (Oswestry Disability Index) decreased 26 points (0–100 scale) and quality of life improved 0.29 points (0 – 1 scale) all of which are statistically significant, clinically meaningful and consistent with previously published LOIS 3-year and 4-year results.

“Now, more than ever, patients, providers and payers require evidence that procedures are safe and effective as demonstrated through long-term results from prospective randomized controlled clinical trials. Five-year outcomes have become the standard by which new technologies are measured to ensure treatment durability,” said Jeffrey Dunn, President, Chief Executive Officer, and Chairman at SI-BONE. “This milestone publication demonstrates the long-term durability of clinical outcomes and radiographic evidence of the effectiveness of the iFuse Implant as a treatment option for patients with SI joint dysfunction.”

The five year results from LOIS demonstrated that improvements in pain, patient function and quality of life demonstrated at 2-years in INSITE and SIFI were durable and sustained at 5 years (Figures 1 and 2).  Independent radiographic analysis of CT scans at 5 years showed a high rate of bony apposition to implants on both the sacral and iliac sides (98%) as well as a high rate of SI joint fusion (88% bridging bone). Patient satisfaction remained high for patients treated with the iFuse Implant.  There were no reported adverse events related to the study device or procedure at 5 years.