A common source of confusion
SI joint pain is frequently mistaken for generic low-back pain, a lumbar disc problem, or recurrent sciatica. That confusion is understandable because the symptoms overlap. Patients may feel pain low in the back, into the buttock, or into the upper leg, especially with standing from a chair, climbing stairs, rolling in bed, or standing on one leg.
The diagnosis matters because the treatment is different. A patient can have an abnormal lumbar MRI and still have the SI joint as the main pain generator. Operating on the wrong structure is the mistake the evaluation is designed to avoid.
How the diagnosis is confirmed
SI joint dysfunction is usually diagnosed through a combination of history, physical exam maneuvers, and selective diagnostic injections. The office exam can raise suspicion, but the diagnosis becomes stronger when image-guided injection into the SI joint produces meaningful and reproducible relief.
That is especially important in patients with prior lumbar fusion, where the SI joint can become a secondary pain generator over time, or in patients whose imaging does not fully explain their symptoms.
When fusion is part of the answer
Most patients start with activity modification, therapy, medication, and injection-based treatment. SI joint fusion is considered only after the diagnosis has been pressure-tested and the pain remains limiting enough to justify surgery. When selected carefully, minimally invasive SI joint fusion can help stabilize a joint that continues to generate pain despite well-run non-operative care.
The key is being certain that the SI joint, and not the lumbar spine or hip, is what actually hurts.