Dissecting Low Back Pain: Sacroiliac joint dysfunction and pain
One reason for low back pain that often eludes diagnosis and often is misdiagnosed and untreated is due to the sacroiliac joint. What is the sacroiliac joint and where is it? To make it simple lets describe it as a joint that links the lower part of the spine (sacrum) with the pelvis (specifically a pelvic bone called ilium). Since it’s a joint that joins the sacrum to the ilium its therefore called the sacroiliac joint (SI joint). There is one sacrum and two ilia therefore there are two SI joints, one on each side. The SI joint has several function of which a primary one is to help reduce and redistribute the force loads from the lower extremities. SI joints are a shock absorber for the spine above it and convert torque from the lower extremities into the rest of the body.
What are the most common sacroiliac joint causes of low back pain?
SI joint dysfunction and pain can develop due to various reasons including trauma, hypermobility, degeneration and inflammation. In case of trauma this can be seen in falls or motor vehicle accidents, but can also be due to repetitive injuries such as in sports or weight lifting. The trauma results in injury to the SI joint supporting ligaments which results in dysfunction and pain. Some people develop SI joint dysfunction and pain due to hypermobility of the joint when there is too much ligamentous laxity of the joint. This can be genetic and seen in patients who are diagnosed with Marfan syndrome and Ehlers-Danlos syndrome. Other reasons for hypermobility of SI joint is seen in pregnancy when hormones released during pregnancy result in SI joint ligamentous laxity. This is a normal part of the process the body prepares the pelvis for birthing however sometimes after the delivery hypermobility of the SI joint persists and SI joint pain can develop. SI joint pain can also develop due to degeneration and osteoarthritis. Arthritis of the SI joint is common especially later in life and if there has been history of trauma and wear and tear. Repetitive and asymmetrical stress to the SI joint can over time result in wear and tear degeneration of the joint eventually leading to dysfunction and pain. This can be due to abnormal gait, leg length discrepancies, and spinal deformities (such as scoliosis). SI joint pain can also be due to sacroiliitis or inflammation of the SI joint. There are more then one known causes for sacroiliitis and include infection as well as certain autoimmune conditions like ankylosing spondylitis.
How is it diagnosed?
In case of SI joint pain successful diagnosis is usually achieved with a detailed history and physical exam. While no single physical exam maneuver is diagnostic, its been shown that a combination of specific findings and provocative tests can be essential in determining SI joint dysfunction and pain. The exam should include a number of specific maneuvers and SI joint pain is diagnosed when at least three out of the five provocative maneuvers are positive. Imaging studies (xrays, CT, MRIs) are not definitive for diagnosing SI joint problems and often come back “normal.” However, the imaging might be needed to rule out any red flags like fractures, infection, tumors depending on the clinic scenario, and also may be needed to rule out other causes of pain. A diagnostic image guided SI joint injection can also help confirm SI joint pain if there is immediate post injection pain relief.
What are the treatment options?
Initial treatment in case of acute pain can start with a period of rest, ice, and medication if needed. Rest should be brief, no longer then 3 days as long term rest can result in more dysfunction. If pain persists then an evaluation by a specialist should follow. Once diagnosis of SI joint pain is confirmed treatment typically includes physical therapy to work on strengthening exercises to stabilize SI joint and correct any imbalance. Some bracing like an SI joint belt can also be helpful when there is too much or abnormal mobility of the SI joint. Manual manipulation such as by a chiropractor or a osteopathic doctor can sometimes be useful in cases of SI joint hypomobility. In cases of inflammatory or autoimmune sacroiliitis treatment may need to include antibody therapy and consultation with other specialties like rheumatology. If pain does not improve with conservative means then SI joint steroid injections, nerve blocks and ablations are interventional pain management options. Surgery is not preferred and is usually a last resort.
