So far, we know that back, buttock, and/or leg pain truly caused by sacroiliac joint problems gets better when the joint is injected. The treatment is considered successful if using a combination of a steroid (antiinflammatory) drug and a numbing agent like novacaine (e.g., bupivacaine, lidocaine) reduces the pain by at least 50 per cent. Pain that comes back within the first six weeks after injection is a sign of treatment failure.
This type of injection is both diagnostic (confirms the sacroiliac joint as the problem) and a form of treatment. Long-term relief of pain is achieved in patients with sacroiliac joint dysfunction with seronegative spondyloarthropathy. Spondyloarthropathy refers to an inflammatory joint disease affecting the spine, including the sacrum and sacroiliac joints. Seronegative means blood tests came back negative for rheumatoid factor (RhF). RhF is positive when the joint problem is associated with some form of rheumatoid arthritis.
In this study, interested scientists take it a step further. They tried this same treatment on patients with sacroiliac joint dysfunction who did not have spondyloarthropathy. Studies on the effectiveness of sacroiliac joint blocks in patients without an underlying inflammatory cause have been very limited but have not shown any real benefit.
So what did this study offer in the way of additional information on the use of injections with this select group of patients? Well, first of all it should be noted that patients were carefully selected to be in this study. They all showed at least a 75 per cent improvement in sacroiliac joint pain with two or more injections with triamcinolone acetonide. Triamcinolone acetonide is a more potent type of steroid, being about eight times more effective than the more commonly known prednisone. That confirmed they had a true sacroiliac joint problem.
Then they were followed for an average of 45 weeks (some as long as 72 weeks). Measures of treatment effect were taken using a self-report questionnaire of pain and the Oswestry Disability Index (measure of pain and function). Both of these tests were given to the patients before and after injection treatment. Other data collected on each patient also included age, gender, pain duration, body mass index, and history of lumbar or lumbosacral spinal fusion.
Two-thirds of the patients reported more than 50 per cent improvement in pain that lasted for at least six weeks. Those patients were considered a success. The remaining one-third got pain relief but it wasn’t long lasting enough to be labeled a success. This group ended up going to physical therapy instead of having another injection treatment.
They took a closer look at those who had a successful response to the injection treatment. They were able to see that patients who had a spinal fusion were less likely to improve. They were also more likely to experience treatment failure. Pain relief was not linked with gender, age, body size/weight, or pretreatment pain and disability.
No one is quite sure why lumbar or lumbosacral fusion would affect the outcome. It has been suggested that the fused spinal segments reduce movement and increase stiffness of the spinal complex. The result may be added strain and/or load on the nearby sacroiliac joint. There may be a faster process of sacroiliac joint degeneration when there’s been a fusion.
The authors conclude there may be a role for steroid injection in the treatment of sacroiliac joint pain that is not associated with spondyloarthropathy (inflammatory disease). But it may be a select group as not everyone in this group improved. At least one risk factor identified was spinal fusion. But some patients with spinal fusion did respond favorably to the injection treatment, so there may be other risk factors to consider.