The sacroiliac joint (SIJ) and its associated ligaments connect the spine to the pelvic girdle.
The latter articulates with the hip. Occasionally, the joint or its ligaments can become strained and cause pain that closely mimics sciatica caused by a lumbar herniated disc. The pain starts in the back and radiates down the leg. It can be felt in the hip region or

It is important to make this distinction because herniated lumbar discs do not always cause pain. In fact, many peoples have herniated discs that have never caused pain and are found when a test is done for some other reason! There is no reason to operate on a disc that is not causing any problem.

Strains of the sacroiliac joint are often due to falls or forceful twisting motions. The pain can be severe! It is usually worse when getting up from a chair or climbing stairs and it is often difficult to find a position of comfort. Urinary frequency may occur in women as well as discomfort with bowel movement and sexual intercourse. The pain can be felt as an ache in the whole leg and might involve both legs.

A herniated disc might occur at the same time (often at the L4-5 level because of a ligament between the vertebra and the SI joint) causing concomitant true sciatica. The herniated disc is usually recognized and surgically treated but the pain does not resolve because of the concomitant sacroiliac strain! This is a scenario that I have encountered many times in clinical practice.

Sacroiliac pain is due to subluxation of the joint. The range of movement is small and therefore cannot be detected on XRs. Sacroiliac dysfunction must be diagnosed by clinical exam.

The two sides are compared for symmetry with the painful side considered the abnormal one. The ilium can be rotated anteriorly or posteriorly. There can be an upslip (the most frequent) or downslip. Often, the sacrum is also rotated, placing strain on the facets (the joints of the spine). Those subluxations can be determined by clinical examination and reduced with various manipulations and exercises.

Some other tests are meant to mobilize the joint and exacerbate the pain to confirm the diagnosis but the condition can be so painful that they are not often used.

Numbing the sacroiliac joint with local anesthesia usually confirms the diagnosis if the pain disappears while the medication is active. Adding steroids (cortisone derivatives) will decrease the inflammation and help treatment. However, if the joint remains in an abnormal position, the pain usually comes back.

Conservative treatment consists in realigning the joint with appropriate manipulations, then strengthening the tendons and surrounding muscles with exercises to keep it in position. Sometimes, a sacroiliac belt that tightens around the hips might be of use.

Some clinicians use sclerotherapy (prolotherapy). This is a technique where irritant substances are injected in the ligaments and tendons that surround the joint to produce inflammation and scarring. This thickens the ligaments and may stabilize the joint. However, this technique is not presently accepted by the medical community at large and most of the insurance companies.

Finally, if all else fails, the joint may be fixated and fused. Fixation is done with two or three screws inserted through the gluteus muscle across the sacroiliac joint, using XR guidance. The edge of the iliac crest overlapping the joint is often used as graft material to be inserted inside the joint space after curetting the cartilages. The most important point is to realign the joint as much as possible for the surgery.

The procedure itself takes about an hour. Most often, patients are discharged the same day or the next morning. Stitches or staples are removed within 10 to 14 days. I prefer patients to avoid weight bearing on the side of the surgery for about 1 week. After that, a progressive exercise program is started including a pelvic stabilization program and progressive walking and swimming.

Possible complications are infection and post-operative hemorrhage. The joint could be misaligned. The screws could touch and irritate the surrounding nerves or nerve roots. The screws would then need to be repositioned. The success rate is about 85% and the complication rate about 1-2%. Other possible complications are irritation of a local muscle, the piriformis, which can become painful. Nonunion of the fusion occurs in about 8% and is often related to smoking.

An important point to remember for women of childbearing age is that fusion of the joint decreases the mobility of the pelvis during childbirth, and a C-section might be necessary!