If a patient presents with low back pain that radiates postero-anteriorly to the pubis, or laterally around the pelvis to the antero-lateral thigh or groin, suspect the Wikipedia reference-linkSIJ. Piriformis & lumbar erector spinae muscle guarding tension, and tenderness over the ileo- sacral area is usually present. Sit to stand, sitting, and sleeping pain are common.
Dry needling of trigger points, electrotherapy techniques, muscle stretching, core stability strengthening are the first treatment options. Home gentle mobilisation exercises are given, which reduce muscle tension. If the above fails, a rigid SIJ belt , eg SI-Loc is very helpful. Severe cases requires the use of the belt for 4 to 6 weeks 24 hours per day. The belt must be applied correctly & MUST be tightened in supine, not standing. Gradual weaning of the belt is then advised over a prolonged period, dependent upon symptoms, possibly 4 month in severe cases.
If the belt does not provide any relief on the first fitting in the clinic, it probably won't help, and the diagnosis should be checked. Referral on to a rheumatologist or doctor for the assessment of a cortisone injection is required sometimes.