Concomitant sacroiliac joint pain in patients with lumbar disc herniation: case series.

Recent studies have shown that not all lumbar disc herniations are symptomatic and that when followed longitudinally, these patients develop back pain independent of the previous imaging study. This is a case report of two patients with radicular symptoms and lumbar disc herniations that underwent diagnostic injections to locate their pain generator. Both patients failed to respond to transforaminal epidural steroid injections. Transforaminal injections can be diagnostically sensitive for radicular pain but not specific. This is a direct result of the spread of medication to other levels in the epidural space, thus affecting multiple levels of innervation. Follow-up with two sacroiliac injections gave significant relief of their pain. They were both treated conservatively for sacroiliac joint pain and did well. One remained pain free after several months and the second remained with minimal pain until she presented again in her 3rd month of pregnancy with return of her pain. The differential diagnosis of lumbar radicular pain is discussed as well as the authors' experience in using diagnostic injections.