What causes SI pain?
The Sacroiliac joint has been to be a cause of severe, limiting back pain for many years. We know that the SI joint has a central role in the force transmission and function of the body, and that it has a tremendous nerve supply. Though the exact mechanism of the pain is elusive, the character of the pain is similar to the severe orthopaedic pain which leads to other types of orthopaedic interventions. Because of the difficulties of accurate diagnosis and treatment, it is necessarily to evaluate the patient for other possible causes of pain, convincing degrees of disabling pain, and a clinical situation where a surgical intervention can reliably benefit the patient.
Why does the SI joint fail?
The sacroiliac joint may fail because of congenital malformation, stress transfer from old surgery, injury (from a fall or previous bone graft harvest) or overuse. Often the failure is acute but it may occur chronically. It is essential that other, more traditional causes of regional pain be excluded when the diagnosis of SI pain is considered. This includes the consideration of hip joint pain (degenerative arthritis of the hip), mechanical back syndromes (degenerative disc, herniated disc) and other non-orthopaedic problems (aneurysm, kidney stone).
How is the diagnosis established?
When the patient’s condition is severely limited, a differential intraarticular block of the SI joint is considered. Passive imaging (plain films, MRI and CT) of the SI joint (even when severely painful) is either normal or non-specific. Provocative injection (like discogram) is not effective. Differential anesthesia of the joint (by an orthopaedist or a skilled interventional radiologist provides confirming evidence when the diagnosis is suggested by history, physical exam and exclusion of pertinent negatives, (discussed above). Such testing must be cautiously interpreted along with the exam and other testing since other regional tests (like selective nerve root injection, or positive MRI images may confuse the findings.
When is fusion surgery recommended?
When the diagnosis is established and the symptoms are severe, and the patient can accept the risk/benefit ratio, fusion surgery is recommended. Such surgery, done through this office, is done with all possible variables maximized to ensure solid fusion. The surgery includes 1. A very cautious planar approach to the joint, which preserves important functioning anatomy (muscles, fascia, nerves, lumbar spine) 2. Cautious preparation of the joint (both intrarticularly and extraarticularly) 3. Carefully selected internal stabilization, and 4. cautious anatomic repair. Bone graft is harvested and stimulation methods are added when there are comorbidities or certain psychosocial risks, since the effect of a failure of healing is especially severe in such a patients. Patients are placed on crutches, and activity limited to partial weight bearing on the affected side for six weeks. Patients do not suffer stiffness in the traditional sense, or damaging transfer of forces. Bilateral fusion are unusual and seem to follow damaging transfer of forces from fused lumbar discs (especially multilevel), or congenital anomaly.
When is fusion surgery not recommended?
It should be understood that the great majority of such patients are not “sacroiliitis”, or inflammation of the SI joint by mechanisms related to inflammatory disease like infection, rheumatoid arthritis, or rheumatoid variants (lupus, ankylosing spondylitis). Though this office sees those types of problems also, the character of complaint is rarely mechanical/orthopaedic, and they have never required sacroiliac fusion.
How is the surgery done?
The experience in this office has included use of several methods of fusion, including anterior (within the pelvis), transgluteal, through the iliac bone, and from posterior (with and without internal fixation. It was found that a posterior approach from near the midline provides a much smaller incision, better anatomic approach and a good visualization of the SI joint. By open methods, spinal fusion cages (either RAY cages or BAK implants) are used as a way of introducing a slightly oversized device into the joint for “ligamentotaxis” (pushing against stretched joints to restore anatomy, contain the fusion biology, and restrain motion.).
What if I have other health issues?
We minimize risks wherever possible. Comorbidities (diabetes, age, pulmono-cardiac) are evaluated and treatment maximized in the preop process. Though exceptions are conceivable, this office tries never to do smokers, because of specific experience with non-union or bone quality.
Does the surgery help?
The results of the surgery are encouraging. To date, it seems to provide a reliable method of stabilizing the joint and treating the SI pain. For more information, please view our Testimonials page.
For more illustrations, please visit the Sacroiliac Section of our glossary