A Wedge Issue

Sacroiliac joint dysfunction is an underlying cause of many back pain cases

Vol. 22 • Issue 22 • Page 16

Si Dysfunction

Low-back pain is very common and can persist from a few days to months to several years. Each year, millions of Americans spend at least $50 billion on solving low-back pain, the most common cause of job-related disability and a leading contributor to missed work.1 Common among the numerous contributors to low back pain is malalignment of the sacroiliac joint (SIJ), resulting in back sprain. This condition often remains undiagnosed or misdiagnosed, resulting in mismanagement and in rare cases unnecessary surgery.

Back Anatomy and Physiology

The SIJs are designed primarily for stability. The SIJs can withstand a medially directed force six times greater than the lumbar spine, but only half the axial torsion and 1/20th the axial compression load of the lumbar spine.2 The human hip girdle comprises three large bones-the sacrum and the right and left iliac bones. These bones are joined at three relatively immobile joints. The sacrum connects with the fifth lumbar vertebra at the lumbosacral joint and with the iliac bones at the SIJs. The SIJs are critical in transferring the load-bearing of the upper body to the lower body.

It is not clearly understood why the SIJs sometimes become painful, although it is believed to be a result of a limitation in its normal motion. Osteoarthritis resulting from wear or damage to the cartilage is the most common cause of SIJ dysfunction; the combination of vertical compression and rapid rotation (e.g., twisting while carrying a heavy object) also contributes to SIJ dysfunction. Pregnancy is a predisposing factor to SIJ dysfunction because of lordotic posture, weight gain, mechanical trauma of childbirth and increased ligament flexibility (laxity).

Other causes of SIJ injury or pain include motor vehicle accidents, especially when a driver slams a foot on the brake pedal before a collision, and the force of the impact is transmitted through the foot and leg to the twisting pelvis. A fall on one side of buttocks can cause a similar twisting motion and injury, which may injure the ligaments around the joint.

Additional causes that may also contribute to SIJ dysfunction are a leg-length discrepancy, gait abnormalities, prolonged vigorous exercise, scoliosis and spinal fusion to the sacrum. Lumbar spine surgery also has been reported to trigger SIJ pain subsequent to ligament weakening and postsurgical hypermobility. Mechanical dysfunction, inflammation, infection, trauma and degeneration all have been reported as causes of SIJ.

Prevalence and Symptoms

The lifetime rate of experiencing low back pain approaches 95 percent. A retrospective review of 1,293 cases of low-back pain treated over a 12-year period revealed that SIJ syndrome and posterior joint syndromes are the most common referred-pain syndromes, whereas herniated disks and lateral spinal stenosis are the most common nerve root compression lesions.3 Referred pain syndromes are more common and usually mimic the clinical presentation of nerve root compression. Combined lesions occurred in 33.5 percent of cases studied; lateral spinal stenosis and herniated nucleus pulposus coexisted in 17.7 percent of cases. In 30 percent of spondylolisthesis cases, the SIJ was the source of pain.3

The most common SIJ dysfunction symptom is pain. The pain experienced with SIJ dysfunction typically is unilateral or bilateral pain occurring very low in the back or in the buttocks; middle-aged women most commonly are affected. SIJ dysfunction symptoms can mimic the pain caused by a lumbar disc herniation (i.e., pain on either side of the low-back with radicular symptoms). Pain typically is described as a dull ache, or as sharp, stabbing or knife-like. Some patients also may describe groin and thigh pain.

SIJ inflammation and arthritis also can cause stiffness and a burning sensation in the pelvis. With an inflammatory process, symptoms usually are worse in the morning and resolve with exercise. Pain on sitting is the most common complaint and typically is aggravated by sitting on a hard seat or sitting for a long period. Rising from sitting to a standing position also aggravates the pain. Patients often state that lying down decreases pain intensity.


Diagnosing the cause of back pain is difficult and challenging because multiple structures can cause pain. However, an accurate diagnosis is key to providing successful treatment of a back injury. The first step in diagnosing SIJ dysfunction is a well documented and thorough history and physical examination. It is imperative to determine whether a patient has any underlying disorders that could be causing the pain (e.g., leg-length discrepancy, a history of trauma).

Included in the differential diagnosis are spinal causes of pain (e.g., facet joint injury, lateral lumbar disk fissure, lateral recess stenosis, degenerative spondylolisthesis), pain arising in the hip (e.g., avascular necrosis, fracture), muscular or myofascial causes (e.g., piriformis syndrome), infection, malignancy and inflammatory disease.

Patients with SIJ dysfunction often can identify with one finger the site of the pain; palpation may be the most reliable indication of SIJ pain. Usually, pain is reproduced upon pressing a thumb directly onto one particular spot in the dimple of the sacral sulcus (the Fortin finger test).4 A positive Fortin finger test is a quick and simple way of initially identifying patients with SIJ.4 Pain provocation tests aim to stress the structure in an attempt to reproduce the patient’s pain. Two of the most commonly used pain provocation tests are the Gaenslen test and the Patrick test.

The Gaenslen test is performed with the patient in the supine position, with the knee and hip on one side held in a flexed position. The patient is positioned so that one gluteal muscle extends over the table’s edge, while the other remains on it. The unsupported leg is allowed to drop over the edge; the examiner presses down on that leg to produce hip hyperextension. This maneuver stresses both SIJs simultaneously and elicits pain on the affected joints.

The Patrick test also is performed with the patient in the supine position. The knee and thigh of one leg are flexed, and the external malleolus of that leg is placed on the patella of the other leg. The examiner forces external rotation by pushing down on the flexed knee while stabilizing the opposite iliac crest. Pain elicited in the SIJ, buttocks or groin is a positive test and is indicative of disease or injury in that joint. The Patrick test also is known as the FABERE test, an acronym comprising the movements needed to elicit a positive sign: flexion, abduction, external rotation and extension.

Patients also have pain along the iliotibial band, which runs down the lateral thigh from the hip to the knee and can become distorted, tight or overworked when the pelvis is not functioning correctly.

Motor strength examination is challenging and may yield to weakness; however, this is mostly because of the pain elicited during the examination. A true neurogenic weakness, numbness or loss of reflex should warn a different etiology, such as nerve root injury.


After the diagnosis of SIJ dysfunction is established, specifically directed treatment can lead to satisfying results. A variety of therapies are available for the treatment of SIJ pain.

Treatment for SIJ pain should address the underlying pathology. For example, if the cause is leg-length discrepancy, then shoe inserts may be beneficial. SIJ pain resulting from altered gait mechanics and spine malalignment may benefit from physical therapy, during which a physical therapist can teach stretching or pelvis-stabilizing exercises that can help reduce pain. Ultrasonography, deep and superficial heat and superficial cold treatments also may be beneficial. A sacroiliac belt, which wraps around the hips and helps stabilize the SIJ, also may be beneficial.

Nonsteroidal anti-inflammatory drugs (NSAIDs) often are used in treating SIJ pain and often are very effective. Should NSAIDs fail to reduce the pain, SIJ injections also are very effective and can be both diagnostic and therapeutic. Because patients usually have pain in the hip of the affected side, injections in the SIJ along with injection in the greater trochanteric bursae result in satisfactory outcomes. Pain relief from the injections may last from a day to months. Injections generally may be repeated up to three times a year.

If all else fails, fusion of the SIJ to prevent all motion at the joint may be an option. Fusion should be considered only when other conservative measures fail.

SIJ is one of the most common causes of low-back pain and leg pain. But since no standard diagnostic tests are available other than a thorough history and physical examination, many patients are misdiagnosed and undergo surgical correction of an incidentally found spondylolisthesis or a disk herniation, only to find that the same symptoms continue postoperatively.

Patients with low-back pain should be thoroughly examined, and SIJ pain should be among the differential diagnoses of low-back pain.

References are available at www.advanceweb.com/pt under the Resources tab.

Gohar Abrahamyan is senior physician assistant in neurosurgery at the Maxine Dunitz Neurosurgical Institute at Cedars-Sinai Medical Center in Los Angeles.

Heat and Cold for Back Pain

Several recent studies have confirmed the value of heat therapy in pain control. Dr. Brian King of the University College London Department of Physiology recently led a study that pinpointed the molecular basis for the longstanding theory that heat applied to skin provides relief from internal pain. “The heat doesn’t just provide comfort and have a placebo effect-it actually deactivates the pain at a molecular level in much the same way as pharmaceutical painkillers work,” said Dr. King.
Dr. King’s team found that applying heat of at least 105 degrees to a painful area would switch on the heat receptors located at the site of injury. These receptors, in turn, block the effect of chemical messengers that cause pain to be detected by the body.
In a study for the American Pain Society’s American College of Physicians, Chou and Huffman studied acupuncture, back schools, psychological therapies, exercise therapy, functional restoration, interdisciplinary therapy, massage, physical therapies, spinal manipulation, and yoga for acute or chronic low back pain (with or without leg pain). They concluded that, for acute low back pain, the only therapy with good evidence of effectiveness is the application of superficial heat.
Cold therapy can provide the same positive results, and is usually recommended as soon as possible after an injury has occurred, with continuing application for the next 24-48 hours. Using cold therapy to treat injuries is one of the oldest methods of pain control, and is safe and effective at reducing swelling, relieving pain and decreasing muscle spasms.

Here are some tips when purchasing a heating unit:

  • Get a heating unit large enough for effective therapy to the entire area. Apply heat to the whole area, not just one little spot.
  • Get a unit that’s capable of intense heat. Just warming your skin a bit won’t do the trick.
  • Moist heat is critical for maximum benefit. Moist heat penetrates much deeper into tissues than dry heat. Some heat therapy products have a special cover that absorbs moisture from the atmosphere to provide a light moisture vapor automatically at every use, thereby ensuring effective moist heat. Others have an area where you can safely add a damp cloth to increase the available moisture.
  • Choose a heavier product that lies on the patient and shapes around curves for good contact. Even temperature distribution is important. You shouldn’t lie on top of the heating pad-it should lie on top of you, and form closely to your skin.

If you have an acute injury, a frozen bag of peas makes a quick emergency cold pack. For long-term use, however, select a cold pack that freezes quickly and retains temperatures longer, and that remains soft and pliable, even when fully frozen. Fabric covers can protect skin, retain cold temperatures and prevent condensation.

Additional tips when using thermal therapy:

  • Be proactive. The longer joints stay immobile, the harder it gets to recover fully.
  • Be patient and persistent. It’s human nature to want the “instant fix” that doesn’t require any effort or problems. What doctors describe as “soft tissue” injury (to muscles, tendons and ligaments) often takes longer to fully heal than a broken bone.

1. National Institutes of Health, National Institute of Neurological Disorders and Stroke. Low Back Pain Fact Sheet. NIH publication 03-5161. http://www.ninds.nih.gov/disorders/backpain/detail_backpain.htm. Published July 2003. Updated August 3, 2009. Accessed September 28, 2009.

2. Dreyfuss, P., Dreyer, S.J., Cole, A., & Mayo, K. (2004). Sacroiliac joint pain. The Journal of the American Academy of Orthopaedic Surgeons, 12(4), 255-265.

3. Bernard, T.N., & Kirkaldy-Willis, W.H. (1987). Recognizing specific characteristics of nonspecific low back pain. Clinical Orthopaedics & Related Research, 217, 266-280.

4. Fortin, J.D., & Falco, F.J. (1997). The Fortin finger test: An indicator of sacroiliac pain. American Journal of Orthopedics, 26(7), 477-480.

About The Author