Is the SI Joint A Pain Generator That Can Be Addressed by Fusion?

Often overlooked in a diagnostic workup for lower back pain, the sacroiliac joints are estimated to be the pain generator in 15% to 25% of patients1.


Causes of sacroiliac (SI) joint pain range from trauma to ankylosing spondylitis. Other causes include mechanical stress, prior spinal fusion, pregnancy, gout, obesity, and aging. Once a SI joint is identified as a pain generator, the question turns to treatment options.


Conservative treatments include physical therapy, chiropractic treatment, and stretching exercises can alleviate the pain in many patients. Anti-inflammatory medications, heat, and braces may also be used. For those whose paint persists, fluoroscopy-guided injections of corticosteroids or analgesics may be helpful. Nerve ablation may also be an option.

When conservative treatment is ineffective, surgery had been rarely considered until the introduction of minimally invasive fusion in 2004.2 Since then a number of studies, and reviews have concluded that MIS SI joint fusion appears to be a safe and effective procedure for the treatment of pain generating from the sacroiliac joint.


A retrospective 2012 study3 of 50 consecutive patients treated with minimally invasive SI joint fusion using triangular titanium implants by a single surgeon resulted in no change from baseline scores for lifting ability, with patient-reported satisfaction scores above 90% at 3 months, and above 80% at 6- and 12-months post-surgery.

In a 2013 prospective study4 involving 94 patients treated with SI joint fusion at 23 sites in the US, the visual analog scale (VAS) scores improved from a baseline of 76 to 29 at six months post-surgery, and the Oswestry Disability Index (ODI) scores improved from 55.3 to 38.9, leading the researchers to conclude that MIS joint fusion produced high rates of pain improvement, function and patient satisfaction.

Several types of devices have been used in these procedures including triangular titanium cages, titanium plasma coated implants, hollow modular screws, allograft dowels, autograft iliac bone plugs.

The consistent success of MIS SI joint fusion in multiple studies led the International Society for the Advancement of Spine Surgery (ISASS) to issue a policy statement in 2014.5 The policy concluded in part that not only is the prevalence of SI Joint pain high but is most likely under diagnosed. In reviewing the literature, the ISASS concluded that MIS for SI joint pain should be considered in eligible patients.

Minimally invasive SI joint fusion is a safe and effective procedure for patients with unremitting pain due to SI joint disorders,” the reviewers wrote. “Published literature consistently reports a low re-operation rate (<5%) along with highly favorable patient outcomes; 88% average reported rate of clinically significant reduction in pain. Furthermore, these outcomes are consistent, replicable and durable across surgeons and geographic regions.”

With the goal of achieving superior surgical outcomes for patients, Omnia Medical's PsiF (Posterior SI Fusion System) offers innovative instrumentation for reproducible results. PsiF allows for a familiar prone patient position and identifiable landmarks for initial incision and has a well-designed implant made of structural allograft bone for easy posterior insertion into the SI joint.

Omnia Medical’s mission is to develop novel products that reduce operative time through safe and reproducible instrumentation, while achieving superior surgical outcomes. Our ongoing collaborations with surgeons help us achieve that by providing continuous insight into developments for surgical needs and patient outcomes. For more information contact us by email at This email address is being protected from spambots. You need JavaScript enabled to view it., or by phone at 304-413-4851.

  1. 1.Pain Physician. 2012 May-Jun;15(3):E305-44
  2. 2.Eur Spine J. 2004 May; 13(3): 253–256
  3. 3.Open Orthop J. 2012; 6: 495–502
  4. 4.Med Devices (Auckl). 2013; 6: 219–229.
  5. 5.Int J Spine Surg. 2014; 8: 25.
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