Sacroiliac (SI) Joint Fusion Simplified
Sacroiliac (SI) Joint Anatomy and Function
Sacroiliac (SI) Joint Anatomy and Function
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| Anterior view of Sacroiliac (SI) Joint |
The Sacroiliac (SI) Joint’s primary responsibility is to transfer the weight of the upper body to the lower extremities. In the
upper portion of the joint, the sacrum and the ilium are not in contact but rather connected with powerful posterior, inter-osseous,
and anterior ligaments. The anterior and the lower half of the joint is a typical synovial joint with hyaline cartilage on the joint
surfaces. The Sacroiliac (SI) Joint is an axial joint with an approximate surface of 17.5 square cm. The joint surface is smooth
in juveniles and becomes irregular over time. Motion (primarily rotation) decreases with aging, and increased motion is associated
with pregnancy.
The Sacroiliac (SI) Joint is stabilized by a network of ligaments and muscles, which also limit motion in all planes of movement.
The normal Sacroiliac (SI) Joint has a small amount of normal motion of approximately 2-4 mm of movement in any direction. The
Sacroiliac (SI) ligaments in women are less stiff than men’s, allowing the mobility necessary for childbirth.
Pathology in the Sacroiliac (SI) Joint
Mechanical strain and injury to the Sacroiliac (SI) Joint are produced by either a combination of vertical compression and rapid
rotation (i.e. carrying a heavy object and twisting), or by falls on the backside. Injuries of this type can produce ligamentous laxity
and allow painful abnormal motion. Instability can also arise from lumbar spine surgery in which a large portion of the ilio-lumbar
ligament is injured. Sacroiliac (SI) Joint “hypermobility” pain can also be caused by leg length discrepancy, gait abnormalities,
prolonged, vigorous exercise, vehicular trauma, traumatic birth, and long scoliosis fusions to the sacrum.
Painful sacroiliac arthritis can also arise from autoimmune disorders, such as ankylosing spondylitis, juvenile rheumatoid arthritis,
Reiter’s Syndrome, psoriatic arthritis, and infections including staphylococcus, gonorrhea and TB.
An Advanced Approach to Surgical Management of SI Joint Dysfunction
Up to 25% of all low back pain is SI Joint in origin but the diagnosis of SI Joint disease is frequently overlooked. (Cohen, et al.)
It is common to link low back pain with protruding disc even when neurological signs are absent. (Weksler, et al.)
It is common for pain from SI Joint dysfunction to mimic discogenic or radicular low back pain. (Weksler, et al.)
Many patients go on to receive lumbar fusion instead of SI Joint fusion so SI Joint disease should be strongly considered in differential diagnosis of low back pain. (Weksler, et al.)
Now there is an approach to surgical management of SI Joint dysfunction thats easier and less invasive than traditional open surgery.
The iFuse Implant System consists of porous plasma spray coated implants, surgically inserted across the SI Joint to create fixation leading to fusionfrom the inside.
The iFuse creates a biomechanically rigorous fixation/fusion system, designed to support reliable fixation/fusion and acute weight bearing capacity.
With the iFuse Implant System, there is no need for BMP in conjunction with autologous bone graft or additional pedicle screws, rods or hollow modular anchorage screws or cannulated compression screws or threaded cages within the joint or fracture fixation screws.
iFuse benefits:
- Less invasive than traditional open surgery with no extensive soft tissue stripping
- straightforward surgical approach
- implant profile and design minimizes rotation and micromotion
- rigid titanium implants provide immediate post-op si Joint stability
- porous plasma spray coating with irregular surface designed to support stable bone fixation/fusion
- Larger implant surface area designed to maximize post-surgical weight bearing capacity
- biomechanically rigorous implant designed specifically to stabilize the heavily loaded si Joint
The iFuse Implant System is designed to be the sacroiliac joint fusion/fixation method of choice for spine surgeons.
iFuse is a minimally invasive surgical solution to replace open surgical SI Joint fusion.
With iFuse there's minimal incision size, minimal soft tissue stripping, minimal tendon irritation and reduced risk of infection.
iFuse is a simplified minimally invasive surgical procedure.
Just drill, broach, insert Implants and close.
iFuse has a simple technique which reduces OR time to less than 1 hour.
iFuse has 3X shear and 7X bending strength compared with screws.
iFuse has improved patient perception of stability post-implant.
The incidence of SI joint degeneration in patients was 75% at 5 years post-fusion, which was significantly higher than in the non-fusion group, 38.2%. (Ha, et al.)
Among patients with one-segment fusion, 91% developed SI joint degeneration. (Ha, et al.)
Regardless of whether the fusion includes the sacrum, the SI joint is influenced by increased mechanical stress arising from lumbar/lumbosacral fusion. (Ha, et al.)
Posterolateral lumbar/lumbosacral fusion can be a cause of SIJ degeneration. (Ha, et al.)
