The sacroiliac (SI) joint connects the sacrum, a triangular bone at the base of the spine, with the ilium, the large bone of the pelvis. SI joint dysfunction is a common cause of lower back, hip, and buttock pain, often treated with a targeted injection. This fluoroscopy-guided procedure delivers a mix of local anesthetic and corticosteroid directly into the joint space to confirm the SI joint as the source of pain and provide therapeutic relief. When a patient does not experience lasting pain reduction, it raises questions about the original diagnosis and the next steps in treatment.
Re-evaluating the Source of Pain
A lack of pain relief after an SI joint injection often indicates that the true source of the patient’s discomfort was misidentified. SI joint symptoms—pain in the lower back, buttocks, and sometimes down the leg—frequently mimic other conditions. A comprehensive re-evaluation is necessary to rule out these mimic conditions.
The lumbar spine is a common source of confusion, as conditions such as disc herniation, spinal stenosis, or facet joint arthritis can produce pain patterns nearly identical to SI joint pain. Hip pathology is another frequent culprit, with issues like hip osteoarthritis or labral tears sometimes presenting as pain deep in the buttock or groin area. A thorough physical examination, coupled with diagnostic imaging of the lumbar spine and hip, helps to differentiate these potential pain generators.
In some cases, the pain may be due to an inflammatory condition, such as Ankylosing Spondylitis, which causes systemic inflammation and requires different, often drug-based, treatment. Technical failure of the injection may also be a factor, such as the medication not adequately spreading throughout the joint space. Reviewing the fluoroscopic images from the procedure can help determine if the needle placement or medication dispersion was suboptimal.
Non-Surgical and Minimally Invasive Alternatives
If the SI joint is confirmed as the pain source, but the steroid injection provided little sustained benefit, treatment focuses on stabilizing the joint and interrupting pain signals. Optimized physical therapy is a foundational component, focusing on specific stabilization of the pelvis and core musculature. This includes strengthening the deep abdominal muscles, gluteal muscles, and the muscles that cross the SI joint to improve load transfer efficiency.
Specialized manual therapy techniques may also be incorporated to address joint hypomobility or alignment issues, aiming to restore proper biomechanics. Advanced medication management can be employed concurrently, often involving nerve-specific agents like gabapentinoids or select muscle relaxants that target neuropathic pain. These medications work to quiet overactive nerves contributing to chronic pain, without relying on long-term opioid use.
Radiofrequency Ablation (RFA) is a minimally invasive technique considered before surgery that provides longer-lasting pain relief than a steroid injection. RFA uses heat generated by radio waves to create a controlled lesion on the small sensory nerves that supply the SI joint. This lesion temporarily prevents the nerve from transmitting pain signals to the brain.
Pain relief from RFA typically lasts between six to twelve months, as the nerves will eventually regenerate. The procedure is performed on an outpatient basis and is considered for patients who experience temporary relief from a diagnostic nerve block. For temporary support during high activity, a specialized sacroiliac joint belt can be used to compress the pelvis and provide external stability.
Surgical Stabilization Options
When non-surgical and minimally invasive treatments, including RFA, fail to provide adequate relief for at least six months, surgical intervention may be considered. The primary option for chronic SI joint pain is sacroiliac joint fusion, which permanently stabilizes the joint by promoting bone growth across the joint space, eliminating motion as a source of pain.
Modern approaches favor Minimally Invasive Surgical (MIS) techniques over traditional open surgery, resulting in a smaller incision, reduced blood loss, and faster recovery. During MIS fusion, the surgeon uses image guidance, such as fluoroscopy, to place small titanium implants across the joint. These implants provide immediate mechanical stability while the body’s natural healing process fuses the bones.
The surgical criteria for SI joint fusion are strict, reserving the procedure for carefully selected patients with confirmed pain. Post-operative recovery involves restricted weight-bearing, followed by rehabilitation focused on restoring strength and function. The goal of fusion is to achieve long-term joint stability and a durable reduction in chronic pain.