SACROILIAC JOINT DISEASE (SACROILITIS) Sacroiliac joints are two relatively large joints that connect the spine to the pelvic bones and the sacrum (the bone that lies above your tailbone).  These joints can become inflamed for a number of different reasons.  These could be trauma, general arthritis, ankylosing spondylitis, etc.   The pain is usually located in the lower back, buttocks, hips, and thighs.  It could be on one side or both sides.  The onset is usually gradual and can become worse over time.  Pregnant women are usually at risk for developing SI joints problems.   During pregnancy because of hormonal changes, ligaments become somewhat lax leading to dysfunction of these joints. The treatment is usually initiated with anti-inflammatory agents in combination with physical therapy. In patients that respond only transiently to sacroiliac joint injections, rediofrequncy lesioning of the sacroiliac joint or the nerves supplying the joint will be considered. In selected unresponsive patients, more advanced pain management modalities such as spinal cord stimulation or implantation of intrathecal drug delivery systems might be an option.