Sacroiliac Joint Fusion

What is a Sacroiliac Joint Fusion?

The sacroiliac joint, or "SI joint" is the place where the "sacrum" (the bottom vertebrae of the spine) meets the "ilium," or the wing-shaped bones of the pelvis. In normal circumstances, the joint moves only a few degrees in any one direction. There are two SI joints, on the left and the right, on either side of the sacrum.

Most treatments for SI joint pain do not involve surgery. Physical therapy, chiropractic care, oral medications, and injections into the joint(s) may provide enough relief to avoid an operation. When all conservative measures have failed to provide meaningful improvement for severe SI joint pain, the operative treatment is it to fuse the joint together. This is known as an "SI joint fusion."


Dr. Bjerke performs an SI joint fusion using a minimally invasive ("MIS") technique. Using x-rays and advanced imaging techniques, the incision for a SI joint fusion is generally less than an inch. The cartilage in the SI joint is removed using special instruments. Bone graft material is then placed into the joint to make the joint fuse together. One to three metal screws are then placed across the SI joint to compress the joint together and make it fuse. Patients are asked to limit the amount of weight they place on the side of the fusion for about six weeks while the joint fuses.