The sacroiliac joint (SIJ) formed by the sacrum wedged between the spine and the hip is the subject of ongoing controversy and debate. Diagnosis of problems affecting the sacroiliac joint can be extrememly difficult.
The current tools we have include the patient interview, physical examination, and imaging tests. During the exam, the physician tests motion, carries out palpation and provocative tests, and then orders appropriate imaging tests.
Screening tests are very limited in what they can find so imaging studies (e.g., X-rays, CT, MRI) are often needed. Bone scanning can be done when the surgeon suspects tumors, inflammatory lesions, and other abnormalities.
A newer scanning technique called the fire scan combines CT, SPECT,and bone scan technology to create a colorful image. The CT scan is overlayed with the bone scan to produce an image that clearly shows the anatomy (as does the CT scan) with the sensitivity of the bone scan.
Studies have not been done yet to support the use of fire scans as a valid and reliable diagnostic tool. At the present time, there is no reference standard for making a clear or definite diagnosis of sacroiliac joint problems. Even with imaging studies like the fire scan, sacroiliac pathology can be hard to detect. Results of these test measures are often variable and unreliable.
The surgeon must take each patient on a case-by-case basis and conduct the examination one step at a time. Each diagnostic tool provides some information. The examiner must not lose sight of the big picture (the whole patient) when one finding is positive over another. Taken together, all the individual findings may eventually point to the sacroiliac joint as the cause of the painful symptoms.