iFuse Implant System® Minimally Invasive Arthrodesis

This study is a multicenter randomized controlled, post-market clinical follow-up clinical trial of the iFuse Implant System for SI joint fusion vs. conservative management. Subjects assigned to conservative management may cross over to iFuse after a minimum of 6 months of conservative treatment. Conservative management does not include interventional procedures such as prolotherapy, steroid injections and/or RF ablation.

Inclusion criteria

• Age 21-70 at time of screening
• Patient has lower back pain for >6 months or >18 months for pregnancy induced lower back pain
• Diagnosis of the SI joint as the primary lower back pain generator based on ALL of the following: a. Patient has pain at or close to the posterior superior iliac spine (PSIS) with possible radiation into buttocks, posterior thigh or groin and can point with a single finger to the location of pain (Fortin Finger Test), and b. Patient has at least 3 of 5 physical examination maneuvers specific for SI joint pain, and c. Patient has improvement in lower back pain NRS of at least 50% of the pre injection NRS score after fluoroscopic controlled injection of local anesthetic into affected SI joint(s) (including previous documented test <6 months ago)
• Baseline Oswestry Disability Index (ODI) score of at least 30%
• Baseline lower back pain score of at least 50 on 0-100 point VAS
• Patient has signed study-specific informed consent form
• Patient has the necessary mental capacity to participate and is physically able to comply with study protocol requirements

Exclusion criteria

• Severe lower back pain due to other causes, such as lumbar disc degeneration, lumbar disc herniation, lumbar spondylolisthesis, lumbar spinal stenosis, lumbar facet degeneration, and lumbar vertebral body fracture
• Sacroiliac pathology caused by auto-immune disease (e.g. ankylosing spondylitis) and/or neoplasia (e.g. benign or malignant tumor) and/or crystal arthropathy
• History of recent (<1 year) fracture of the pelvis with documented malunion, non-union of sacrum or ilium or any type of internal fixation of the pelvic ring.
• Spine surgery during the past 12 months.
• Previously diagnosed or suspected osteoporosis (defined as prior T-score <-2.5 or history of osteoporotic fracture)
• Documented osteomalacia or other metabolic bone disease
• Any condition or anatomy that makes treatment with the iFuse Implant System infeasible
• Known allergy to titanium or titanium alloys
• Use of medications known to have detrimental effects on bone quality and soft-tissue healing
• Prominent neurologic condition that would interfere with physical therapy
• Current systemic infection or local infection at the SI joint
• Currently pregnant or planning pregnancy in the next year
• Known or suspected drug or alcohol abuse
• Diagnosed psychiatric disease (e.g., schizophrenia, major depression, personality disorders) that could interfere with study participation
• Patient is participating in an investigational study or has been involved in an investigational study within 3 months of surgery