Si-BONE iFuse Implant System

History of sacroiliac (SI) joint disorders

Sacroiliac (SI) joint disorders and the associated symptoms have been well known for over a century. In fact, in the early 1900s symptoms which seemed to arise from the back were frequently attributed to the sacroiliac (SI) joint, and open surgical procedures were used to treat the joint.
In 1934, a paper was published on the spinal disc as a source of pain in the back. As a result, disc treatment became the most common operation for orthopedic surgeons, and the sacroiliac (SI) joint was all but forgotten.1 Now, 70 years later, orthopedic and spine surgeons have recognized that the disc is not the only source of low back pain (LBP).
According to scientific data, it’s common for pain from the SI joint to mimic disc or low back pain. To avoid unnecessary lumbar spine surgery, SI joint disorders should be strongly considered in low back pain diagnosis.2

  1. Mixter, WJ, and JS Barr. “Rupture of the Intervertebral Disc with Involvement of the Spinal Canal.” New England Journal of Medicine 211, no. 5 (1934): 210–215.
  2. Weksler, Velan, et al. The role of Sacroiliac (SI) Joint dysfunction in the genesis of low back pain: the obvious is not always right. Archives of ortho and trauma surgery. 2007 Dec; 10(127) 858-888. 

Diagnosis of the SI joint as a source of symptoms


Sacroiliac (SI) joint disorders require appropriate interpretation of a patient’s history, clinical exam results, and imaging studies. Often hip pathology and lumbar pathology coexist with SI joint pathology. During physical examination, patients with SI joint disorders exhibit any/all of the following symptoms:

  • Lower back pain (below L5)
  • Sensation of lower extremity: pain, numbness, tingling, weakness
  • Pelvis / buttock pain
  • Hip / groin pain
  • Feeling of leg instability (buckling, giving way)
  • Disturbed sleep patterns
  • Disturbed sitting patterns (unable to sit for long periods, sitting on one side)
  • Pain going from sitting to standing

SI Joint Exam

  • Differential diagnosis to rule out other sources of pain
    • Negative lumbar spine exam
    • Negative hip exam
  • While standing, have the patient point to the location of pain (Fortin Test)
  • Tenderness over SIJ sulcus
  • Single leg stance test may induce pain on supporting side
  • Positive active straight leg raise
  • Pain to palpation inferior to PSIS
  • Provocative Tests1
    • 3 of 5 positive (Distraction, Thigh Thrust, FABER, Compression, Gaenslen’s)
  • Diagnostic injections of the SI joint


When non-surgical options fail


The iFuse Implant System was developed as a minimally invasive surgical option for patients who have failed non-surgical options. Over the last several years more than 20,000 procedures have been performed .

The iFuse Implant System is intended sacroiliac joint fusion. There are potential risks associated with the iFuse Implant System. It may not be appropriate for all patients and all patients may not benefit. For information about the risks, visit:
The iFuse Implant System® consists of titanium implants and associated surgical instruments. Typically, patients receive three triangular-shaped titanium implants. Available implant lengths range from 30mm to 70mm in 5mm increments. These implants are delivered to the sacroiliac (SI) joint using a cannulated delivery system designed to protect soft tissue. The surgery is performed through a 2-3cm incision.
Potential iFuse benefits

  • Minimally invasive surgical (MIS) approach is less invasive than traditional fusion surgery without extensive soft tissue stripping
  • Triangular implant profile minimizes rotation
  • An interference fit between the implant and the adjacent osseous walls
  • Porous titanium plasma spray (TPS) coating allows for biological fixation
  • TPS technology used for decades in other medical applications such as orthopedics and dentistry
  • Designed specifically to stabilize and fuse the heavily loaded SI joint
  • Rigid titanium construction and implant geometry provide immediate stabilization
  • More than thirty published, peer-reviewed articles demonstrate safety and effectiveness of the iFuse procedure.*

With the iFuse Implant System, there is no need for:

  • Preparation of the joint prior to implant
  • BMP or autologous bone graft
  • Additional pedicle screws and rods
  • Hollow modular anchorage screws
  • Cannulated compression screws
  • Threaded cages within the joint
  • Fracture fixation screws

Possible benefits versus traditional surgical SI joint fixation2

  • Smaller incision size
  • Less soft tissue stripping
  • Minimal tendon irritation

Possible benefits of a minimally invasive surgical procedure2

  • MIS procedure with small incision
  • Drill, broach, insert iFuse and close
  • Cannulated delivery system
  • Minimal blood loss

The iFuse Implant System is CE marked as a medical device in the EEA and Switzerland and is intended sacroiliac joint fusion. There are potential risks associated with the iFuse Implant System. It may not be appropriate for all patients and all patients may not benefit. For information about the risks, visit:

  1. Polly, D.W. et al., Neurosurgery. 2015.— Dr. Polly is an investigator on a clinical research study sponsored by SI-BONE. He has no financial interest in SI-BONE. Research was funded by SI-BONE, Inc. A list of additional published studies is available at
  2. Arnold Graham Smith* et al. Open versus minimally invasive sacroiliac joint fusion: a multi-center comparison. Annals of Surgical Innovation and Research 2013, 7:14. *Paid consultant of SI-BONE Inc.

Minimally invasive SI joint fusion
The iFuse Implant System is intended sacroiliac joint fusion. The procedure typically involves the insertion of three small titanium implants across the SI joint, and is designed to stabilize and fuse the SI joint. Implant lengths range from 30mm to 70mm in 5mm increments with 4.0 and 7.0mm diameters. These implants are delivered to the sacroiliac (SI) joint using a cannulated delivery system and soft tissue protection instruments. This minimally invasive procedure is performed through a small incision and requires about one hour of surgical time. The iFuse may potentially minimize complications often seen with open surgery, reduce blood loss, and reduce average length of hospital stay.
The following surgical technique describes the steps for the implantation of the iFuse Implants.
More than thirty published articles have reported on the safety and effectiveness of the iFuse Implant System. iFuse is the only SI joint fusion device with published results from a randomized controlled trial and the only one with clinical studies demonstrating that treatment improved pain, patient function, and quality of life.