Back Pain from the Sacroiliac Joint - Where the Pelvis and Lower Spine Link

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Lower back pain? Do not automatically assume it is due to strained muscles or a spinal disorder. “The source of the problem may actually be a dysfunctional or inflamed sacroiliac joint – something not always easy to determine despite advances in our diagnostic technology,” says interventional pain management specialist Dr.Kaliq Chang with Atlantic Spine Center.

Sacroiliac Joint Location

The sacroiliac joint (SI joint) is one of the largest joints in the body, connecting the sacrum – the bone at the bottom of the spinal column – to the hip bones, The joint serves as both a shock absorber and controller, modifying the torsion, rotational and other mechanical stresses between upper body, pelvis, and legs, and helping transfer loads from upper to lower body when one is standing or walking.

Skeletal Structure

To be more specific, the SI joint is located at the posterior aspect of the pelvis, between the sacrum and the ilium. It is situated slightly below and to the sides of the lower back dimples (dimples of Venus) that are often visible on the skin.

The SI joint is a weight-bearing joint and is surrounded by strong ligaments that provide stability. It has a limited range of motion compared to other joints in the body, as its primary function is to transmit forces from the upper body to the lower body during activities such as walking, running, and lifting.

The SI joint plays a crucial role in maintaining the balance and stability of the pelvis and the entire spine. Dysfunction or injury to the SI joint can lead to sacroiliac joint pain, which may manifest as pain in the lower back, buttocks, hips, or thighs. It can also cause difficulty in walking, standing, or performing activities that involve the pelvis and lower back.

Sacroiliac joint disease is the result of multiple factors. Making diagnosis even more difficult is the commonality of symptoms shared with other disorders. A dysfunctional sacroiliac joint can lead to groin discomfort, pelvic pain, and lower back pain that may radiate to buttocks, hips, and legs – much like indications of spinal stenosis, sciatica, herniated disc, and spine-related osteoarthritis. Oftentimes, SI pain worsens when bending or twisting, walking up the stairs, or turning in bed, explains Dr. Chang, a highly specialized physician on staff at the Atlantic Spine Center in New York and New Jersey.

Repetitive activities like jogging on hard surfaces, constant heavy lifting, or prolonged sitting and direct injury occurring in sports, car crashes, falls, and other traumatic events may stress or damage the sacroiliac joint or cause it to become dysfunctional – either hypermobile and unstable or hypermobile – too fixed and tensed. Other factors that promote SI pain include gait problems resulting from leg length discrepancies or scoliosis; joint and pelvic changes occurring in pregnancy and childbirth; and infection. In an older population, age-related disorders like osteoarthritis and axial spondyloarthritis may deteriorate the SI joint and promote the development of sacroiliitis, joint inflammation.

Clinical statistics indicate as many as 25 percent to 30 percent of cases involving debilitating lumbar pain are traceable to the sacroiliac joint, Dr. Chang says. Authors of a July 2022 article published by the National Library of Medicine write that “diagnosing sacroiliac joint pathology can be challenging. One of the difficulties providers run into in the evaluation of SI joint injury is distinguishing between lower lumbar pain (lumbago) from SI joint pain.” In an earlier report, appearing in Pain Practice, scientists indicate “clinical examination and radiological imaging [are] of limited…value” in diagnosing sacroiliac-joint disease and suggest a “combined battery of tests” may be necessary, including the “gold standard” of injecting an anesthetic into the joint to determine if that temporarily alleviates the pain. But even these injections can create false negatives or false positives, they state.

Complicating matters, even more, are the variations in pain caused by different pathologies impacting the SI joint. “Symptoms can differ depending on whether the disorder is within the joint itself (intra-articular) or is affecting the ligaments and tissues surrounding the joint (extra-articular),” Dr. Chang states. Despite the difficulties, he and other experts contend that diagnosis of SI joint problems is essential. If left untreated, the condition can eventually hamper a patient’s mobility, disrupt sleep, and even lead to depression.

Conservative approaches are the front-line treatments for SI joint pain. These can include periods of rest, applications of heat or ice to the lower back and pelvis, a variety of exercises and stretches, and the use of over-the-counter pain medications. In some instances, the patient may be prescribed a brace or other support appliance. If these measures prove ineffective, an interventional pain management physician may use image-guided injections of corticosteroids into the SI joint to minimize inflammation and eventually reduce and eliminate the pain, Dr. Chang says. Other noninvasive treatments include radiofrequency ablation to quell the pain and restore quality of life.

In limited instances, a patient with ongoing SI dysfunction may be referred for surgery, most commonly a minimally invasive SI joint fusion. But “patients must be carefully selected,” Dr. Chang says. “Although most such procedures are successful, they are not an ironclad guarantee that an SI problem will be resolved. The patient may experience ongoing SI pain afterward or the surgery may transfer more pressure to the pelvis and lower spine, resulting in continuing lower back pain,” according to Dr. Chang.

Not all sources of SI joint damage, like aging-related causes, can be prevented, but individuals can take steps to maximize the health of this joint, Dr. Chang advises. He offers these tips:

  • Before playing any sport, learn and practice proper techniques and wear the recommended protective gear.
  • Exercise in ways that strengthen core muscles.
  • Participate regularly in aerobic pursuits – like swimming, cycling, and walking. These activities improve overall cardiovascular health, reduce blood pressure, enhance lung function, promote weight loss, and are easy on the musculoskeletal frame.
  • Take frequent rest breaks during any repetitive work or recreational activities. Give your joints a break.
  • Limit jogging to indoor or outdoor tracks with surfaces that minimize pressure on joints. Constantly running on concrete, asphalt, or other hard surfaces can cause joint wear and tear.
  • Use proper lifting techniques to prevent undue pressure on the spine or SI joint.

Finally, “if you are experiencing chronic pelvic or lower back pain, especially if that pain is radiating to other parts of the body and causing tingling or numbness in the legs, contact an orthopedic or spine specialist as soon as possible,” Dr. Chang says.

Learn More about the SI Joint in our Video link: