The sacroiliac (SI) joint connects the sacrum, the triangular bone at the base of the spine, to the ilium, the large bone of the pelvis. This joint functions as a shock absorber, transferring forces between the upper body and the legs. Sacroiliac joint fusion is a surgical treatment for chronic SI joint dysfunction, aiming to stabilize the joint by permanently joining the bones together. While this procedure can relieve pain for many patients, it is important to understand the potential drawbacks and negative outcomes before moving forward.
Immediate Surgical Complications
The SI joint fusion procedure, like any invasive surgery, carries a set of risks directly related to the operation itself. These complications are acute and generally occur during or shortly after the surgery. The most common of these include the possibility of infection at the surgical site, which can be superficial or extend deeper into the tissues.
Excessive bleeding and the formation of a hematoma, a collection of clotted blood, can also occur in the surgical area. Since the SI joint is located near several important nerves, there is a risk of nerve injury, such as irritation or damage to the cluneal nerves or the sciatic nerve. This nerve damage can lead to new pain, numbness, or weakness in the leg.
Persistent Pain After Surgery
The most significant downside of SI joint fusion is the possibility of persistent pain, meaning the procedure fails to achieve its primary goal of relief. One reason for this is a non-union, where the bones do not fuse completely, leaving the underlying joint instability and movement that causes pain unresolved. This failure to fuse may require a second surgery to correct the issue.
Pain may also persist because the original diagnosis was inaccurate, and the pain was actually originating from another source, such as the lumbar spine or hip. Even with a successful fusion, some patients experience pain recurrence due to inflammation, the development of scar tissue, or the altered biomechanics of the pelvis. The presence of hardware itself can also cause discomfort or abnormal sensations, regardless of the fusion status.
Biomechanical Stress on Adjacent Joints
Fusing the SI joint eliminates the small but significant amount of motion it normally provides, which can shift mechanical stress to the surrounding areas. This phenomenon is similar to the concept of adjacent segment disease seen in spinal fusions. By restricting movement at the SI joint, the load-bearing requirements are transferred to the joints above and below the fused segment.
The lumbar spine, particularly the L5-S1 segment, and the hip joint are the primary joints adjacent to the fusion that absorb this increased strain. This transfer of forces can accelerate degeneration or the development of arthritis in these neighboring joints, potentially leading to new pain syndromes years after the initial SI joint procedure.
Long-Term Recovery and Hardware Concerns
The recovery period following SI joint fusion is often extensive, requiring several months for full resolution and bone consolidation. Patients are typically advised to limit weight-bearing activities for an extended period, often three to four weeks, necessitating the use of a cane or walker. Complete bone fusion and a return to unrestricted activity generally take six to twelve months, representing a substantial commitment of time and restricted mobility.
The hardware used to stabilize the joint also presents its own set of long-term risks. These implants can fail, either by loosening, migrating, or even breaking over time, which may require a revision surgery to address the issue. The presence of metal hardware can also complicate future medical procedures, such as interfering with certain types of imaging studies or diagnostic tests. In rare cases, a patient may experience a sensitivity or allergic reaction to the metal components used in the implant.