Pain in the Butt…
A source of controversy for many physicians, the diagnosis and treatment of the sacroiliac joint (SIJ) as a source of pain is often overlooked. Although it can be a significant percent of those suffering with low back and buttock pain, many physicians refuse to recognize its connection to low back pain. This unfortunately subjects patients to pain that perpetuates and forces them to continue to suffer without relief.
As observed in a report from Schwarzer et al. in 1995 the prevalence of SIJ pain can be at least 13 percent and possibly as high as 30 percent in patients with low back and buttock pain. To provide a better understanding of why SIJ can be controversial, I will discuss the anatomy of the SIJ, evaluation, and treatment of the SIJ pain.
The SIJ is a diarthrodial joint, between the sacrum and ilium on the right and left of the posterior pelvis region. The joint is a variably shaped capsule with synovial fluid and hyaline cartilage on the sacral side and fibro cartilage on the iliac side. There are a multitude of ligaments and muscles that support it. The SIJ is more mobile in youth than later in life. The upper two thirds of the joint become more fibrotic in adulthood. Although the female pelvis is more mobile to accommodate pregnancy and parturition the prevalence of SIJ pain seems to be equal among males and females.
The pain that arises from a dysfunctional SI joint can vary among patients but for the most part there are basic similarities. The pains are usually located over the joint itself which is in the upper buttock areas. The pain can be described as sharp, aching, dull, numbing and even a combination of those symptoms is sometimes seen. The pains can radiate down the buttock and even mimic sciatic pains. Their pain can be intense enough to cause patients to limp and sit in awkward positions.
Diagnosing SIJ pains can be very challenging which is why many doctors refuse to recognize it as the cause of the pain. There is a wide array of physical exam maneuvers to detect SIJ pain. Most can be performed simply during the regular examination and verified by provocation. The Fortin’s Finger test, Fabere maneuver, Gaenslen’s test, Compression test, Gillet test, and Patrick’s test are some of the most commonly employed test. A major problem with these tests however is their poor inter tester reliability and false positive rate of 20 to 30 percent in asymptomatic individuals. No single maneuver is ideally diagnostic for SIJ syndrome but having multiple positive SIJ provocation tests can be somewhat reassuring and would suggest at least that SIJ pain should be part of the differential diagnosis.
Of course as with all patients but especially in these cases a thorough history must be taken to check for pre existing disease or injury, or new trauma and to evaluate the patient’s general health. The physical examination also has to be thorough and should include a Full Neurological examination, motor strength, sensory exam, and reflexes in the lower extremities. When exams are thoroughly performed, inspections can often reveal an asymmetrical pelvis with one crest higher than the other. Other important exams to keep in mind are the measurement of limbs to look for irregularity or detect scoliosis.
Laboratory studies are useful to rule out inflammatory disorders. Radiological studies such as plain film x-rays, are reasonable. Imaging with CT Scans and MRI’s is controversial because it is uncertain whether normal and abnormal radiographic studies can definitively differentiate symptomatic vs. non-symptomatic patients. This is in part to the great variability that exists in SIJ anatomy among patients. A comparison between CT Scan and MRI results on patients with sacroilitis revealed that their diagnostic sensitivity was similar. The MRI, though, did provide distinct information about the disease process in sacroilitis.
Once the diagnosis is established, controlling conditions for mechanical mal positioning can start with pain control, followed by education, modalities, and exercises. Educating patients on proper ergonomic training for bending, lifting and stretching can prevent repeated injury. Deep heat can soften and relax the muscles around the joint and electricity can relax muscle spasms. Mobilization is helpful in restoring SIJ alignment and sacral position. Physicians should keep in mind that injections may be the best option for quickly reducing inflammation along the joint line. These injections contain analgesic and corticosteroids that are placed in the lower third of the joint under fluoroscopic guidance or CT guidance. “Blind” injections with similar drugs can also be effective at reducing pains by decreasing ligament irritation.
Other treatments such as percutaneous radiofrequency neurotomy of the SIJ innervation have been performed with reports of long term relief. Reports though are from case series. Some authors have concluded that in patients with SIJ pain who respond to L4-5 dorsal rami and S1-3 lateral branch blocks, radiofrequency denervation of these nerves appears to be an effective treatment. Unfortunately, these studies consist of a very small test group which currently prevents endorsement of this approach.
Another treatment option is a proliferant injection. This injection instills an irritant such as dextrose along the joint line with the desired result being the thickening of the ligaments or muscle attachments to stabilize the hyper mobile joints. Surgery is only considered when pain is intractable and disabling and the patient has failed to respond to conservative treatments. The surgical treatment would consist of screw fixation.
Complications are minimal with the conservative treatments. Potential complications can include infection, hematoma formation, nerve damage, vascular particulate embolism, and complications related to drug administration.
In conclusion SIJ dysfunction continues to be a pain in the butt to physicians. Until studies with adequate methodology and experimental design are completed, physicians will have to use their best guesses as to the best interventions or treatments to use.
Raul G. Martinez, MD is a diplomat of the American Board of Anesthesiology. He completed his post-doctorate Fellowship in Pain Medicine from the University of Texas Health Science Center and has been in private practice since 1999. His offices are located in the Medical Center, Stone Oak, Alamo Heights and Southeast San Antonio. For an appointment call (210) 447-6333. Visit www.cipm.com for more information.
