The Sacroiliac Joint
The sacroiliac joint, or SIJ, is a complex joint composed of the joining of two contoured bony surfaces by strong ligamentous connections. The joint normally allows for a small amount of movement that is important for small amounts of torsional flexibility of the pelvis while walking, as well as for expansion of the pelvis during childbirth. Trauma or torsional stress to the pelvis can cause injury, misalignment, and pain arising from the joint itself or the supporting ligaments. When injured, there is generally pain and tenderness overlying the backside of the joint. There are often associated alignment problems that can be detected through careful physical examination by a properly trained and skilled spine physician or allied practitioner.
Sacroiliac joint pain and dysfunction can be treated through the use of manual therapies, such as chiropractic, osteopathic or physical therapies, often assisted by the use of heat, cold or other physical modalities, and therapeutic exercise. Some sacroiliac joint dysfunctions can also be treated independently through self-mobilization techniques for the pelvis and joint. Muscle retraining (neuromuscular re-education) should be carried out by a physical therapist with specific training and experience with sacroiliac joint related therapy and rehabilitation methods. Sacroiliac joint belts are sometimes used. Various medications, including anti-inflammatories (NSAIDs) can also be used.
Sacroiliac joint pain can be more specifically diagnosed, as well as treated, through the use of the injection of numbing medication (local anesthetics) and corticosteroids into the joint. This procedure can only be carried out with certainty using image-guidance such a fluoroscopy or CT scan. The SIJ intra-articular joint injection of contrast provides an arthrogram, or picture of the joint and the surrounding capsule. This is important for documentation of the accuracy of the injection and to determine if there has been an injury to the joint capsule with leakage of the contrast. The SIJ injection may, in some people, provide months or more of relief. In select cases, when these conservative measures are not successful in relieving pain, the small nerve branches that travel along the back side of the sacrum to the SIJ can be targeted and cauterized using radiofrequency neurotomy techniques. Sacroiliac joint fusion, using minimally invasive surgical techniques, is now an option for those people with sacroiliac joint pain who fail treatment efforts with conservative measures and yet remain sufficiently disabled by their pain to warrant surgery.
For a detailed review, with references, of sacroiliac joint related pain treatment with radiofrequency neurotomies (RFN) and related background information, go to: SIJ RFN Review within this website.
Image key: The upper left image is of the sacrum from behind and the right, showing the right sacral surface of the sacroiliac joint (SIJ). The next two images are of the pelvis and both SIJs from behind. The left image shows the deeper ligaments and the image on the right shows another layer of ligaments and some of the deeper muscles of the back (including multifidi of the back and piriformis of the pelvis). The image on the bottom shows the pelvis from the front showing the ligaments and piriformis and coccygeus muscles.