The sacroiliac (SI) joints are formed by the connection of the sacrum and the right and left iliac bones. The sacrum is the triangular-shaped bone in the lower portion of the spine, below the lumbar spine. While most of the bones (vertebrae) of the spine are mobile, the sacrum is made up of five vertebrae that are fused together and do not move. The iliac bones are the two large bones that make up the pelvis. As a result, the SI joints connect the spine to the pelvis. The sacrum and the iliac bones (ileum) are held together by a collection of strong ligaments. There is relatively little motion at the SI joints. There are normally less than 4 degrees of rotation and 2 mm of translation at these joints.
Indications
Percutaneous minimally invasive fusion/stabilization of the sacroiliac joint (SIJ) for the treatment of back pain is indicated for the treatment of SIJ pain for patients with low back/buttock pain who meet all of the following criteria:
a) Have undergone and failed a minimum six months of intensive non-operative treatment that must include medication optimization, activity modification, and active physical therapy;
b) Patient’s report of non-radiating, unilateral pain that is caudal to the lumbar spine (L5 vertebrae), localized over the posterior SIJ, and consistent with SIJ pain;
c) Localized tenderness with palpation of the posterior SIJ in the absence of tenderness of similar severity elsewhere (e.g. greater trochanter, lumbar spine, coccyx) and other obvious sources for their pain do not exist;
d) Positive response to the thigh thrust test OR compression test AND 2 of the following additional provocative tests: Gaenslen’s test, Distraction test, Patrick’s sign;
e) Absence of generalized pain behavior (e.g. somatoform disorder) or generalized pain disorders (e.g. fibromyalgia);
f) Diagnostic imaging studies that include ALL of the following:
1. Imaging (plain radiographs and a CT or MRI) of the SI joint that excludes the presence of destructive lesions (e.g. tumor, infection) or inflammatory arthropathy that would not be properly addressed by percutaneous SIJ fusion;
2. Imaging of the ipsilateral hip (plain radiographs) to rule out osteoarthritis;
3. Imaging of the lumbar spine (CT or MRI) to rule out neural compression or other degenerative condition that can be causing low back or buttock pain;
g) At least 75 percent reduction of pain for the expected duration of the anesthetic used following an image-guided, contrast-enhanced SIJ injection on two separate occasions.
Limitations
Percutaneous SIJ fusion for SIJ pain is not indicated in the presence of:
Systemic arthropathy such as ankylosing spondylitis or rheumatoid arthritis;
Generalized pain behavior (e.g. somatoform disorder) or generalized pain disorder (e.g. fibromyalgia);
Infection, tumor, or fracture;
Acute, traumatic instability of the SIJ;
Neural compression as seen on an MRI or CT that correlates with the patient’s symptoms or other more likely source for their pain.
