Sacroiliac joint pain underlies many cases of lower back pain. It is most frequently caused by the loss of cartilage in the joint that connects the spinal column to the pelvis, which causes the bones to rub against each other and wear down. A chronic and serious form of arthritis called ankylosing spondylitis is sometimes responsible for severe sacroiliac pain. Impaired walking or posture, as well as back injuries from repeated stress, also cause inflammation and pain in the SI joint. Treatment of pain in the sacroiliac joint first involves reducing inflammation and then discovering and managing the underlying condition.
The sacroiliac (SI) joints connect the spinal column to the pelvis at the junction of the sacrum, the triangular-shaped bone at the lower end of the spine, and the right and left iliac bones, the two sides of the pelvis. Unlike many other joints in the body, the SI joints are held together tightly by ligaments and move comparatively little. The cartilage between the joints absorbs the pressure of movement, and its loss causes intense pain when the bones make contact with each other.
Arthritic joint inflammation causes sacroiliac joint pain. Inflammation is commonly present in rheumatoid arthritis when the cartilage has worn away, and is also caused by uric acid crystal build-up characteristic of gout. Other cases of sacroiliac joint pain derive from changes in the types of stress placed on the joint. A limp or odd posture can increase the pressure, which explains why those with injured feet sometimes develop lower back pain. Physical therapy and returning the patient to a normal walking pattern usually resolve this kind of pain.
A particularly severe form of joint damage occurs in ankylosing spondylitis, which causes severe sacroiliac joint pain. This autoimmune disease differentially strikes younger males, and results in the immune system destroying the tissue of the affected joints. Inflammation of the large peripheral joints, fingers, or toes occurs. While it is a systemic disease that can appear anywhere in the body, it very commonly attacks the sacroiliac joint, resulting in permanent damage to the spine and posture. Patients often report lower back stiffness and severe SI pain, especially at night.
Diagnosis of sacroiliac joint pain is often made after patients report lower back complaints. Injections to determine which part of the back is affected, coupled with medical imaging of the joints, confirm the diagnosis. Pain management specialists, rheumatologists, and orthopedic surgeons all contribute to different treatment regimens. Treatment of arthritic SI joints often consists of a regimen of anti-inflammatory drugs and painkillers, though extreme cases may benefit from surgical intervention. Surgery involves stabilizing the bones so they no longer make direct contact, using metallic support to prevent movement.