The sacroiliac (SI) joint is well documented as a potential source for lower back pain (LBP) and it is estimated that SI joint pain affects 15-25% of patients suffering from LBP1. A number of publications have found that SI joint degeneration is present in patients who had previously undergone lumbar fusion surgery and pregnancy related pelvic instability is a common and disabling problem2-3.


Sacroiliac joint fusion has been proven to be a reliable treatment option for patients experiencing SI joint pain. SiJoin is a patented system intended for SI joint fusion for conditions including degenerative sacroilitis and sacroiliac joint disruptions.

  • Proven – Posterior SI joint fusion has been performed since the 1920’s with positive results4
  • High fusion rate – 89.5% fusion rate for posterior SI joint fusion using allograft implants5
  • Improvement in Visual Analog Scale (VAS) – substantial improvement in VAS pain score from 9.1 preoperatively to 3.4 postoperatively5


  • Tried and True Fusion – The SiJoin procedure utilizes a tried and true method for achieving joint fusion by preparing the joint (decortication), stabilizing the joint via cortical allograft implants, and using bone graft material to enhance the potential for fusion across the joint
  • Less risk – Compared to lateral based SI joint methods, the SiJoin procedure minimizes the risk of the neural complications due to the direct posterior approach
  • Flexibility – The surgeon can choose to use a minimally invasive surgery (MIS), mini-open, or an open approach all while allowing for direct visualization of the SI joint
  • Biomechanics – Biomechanical stabilization of SiJoin is equivalent to lateral rod systems by taking advantage of the “lever arm” concept6
  • Revision – Due to its unique design and approach, SiJoin can be used to revised other SI joint fusion procedures
  1. Cohen, Steven P. Sacroiliac Joint Pain: A Comprehensive Review of Anatomy, Diagnosis, and Treatment. Anesth Analg 2005 Nov. 101(5) 1440-53 Review.
  2. Ha, Kee-Yong, et al. Degeneration of Sacroiliac Joint after instrument Lumbar or Lumbosacral Fusion: A Prospective Cohort Study Over Five-Year Follow-up. Spine: 15 May 2008-Volume 33 -Issue 11 -pp 1192-1198
  3. Wu WH, Meijer OG, Uegaki K, et al. Pregnancy related pelvic girdle pain (PPP): Terminology. clinical presentation, and prevalence. Eur Spine J 2004; 13:575-89
  4. Smith-Petersen MN, Rogers WA. End-result study of arthrodesis of the sacroiliac joint for arthritis–traumatic and nontraumatic. J Bone Joint Surg 1926;8:I 18-36
  5. Maguire, Robert A et al. Dual fibular allograft dowel technique for sacroiliac joint arthrodesis. Evidence-Based Spine-Care Journal: 2012 -Volume 3 -Issue 3 – pp 21-28
  6. Data on file at VGI Medical