The Sacroiliac Joint
By Scott Bradley, MD

 

One commonly overlooked cause of lower back pain is degeneration and inflammation of the sacroiliac joint, a complex structure responsible for carrying the weight of the upper body and shifting that load to the legs for walking and standing.  

Unfortunately, damage to an SI joint often does not appear on X-ray, CT or MRI scans, which can lead to misdiagnoses if the condition is not on a physician’s radar. Symptoms also can mimic a pinched nerve, herniated disc, sciatica, or hip arthritis. In fact, I describe SI joint dysfunction as a “great masquerader”. 

Connecting the lumbar spine to the hips, SI joints have irregular surfaces and are surrounded by an intricate network of ligaments and muscles, all designed to limit motion to approximately two to four millimeters in any direction. 

Patients with SI joint dysfunction typically present with pain at the very top of the buttocks, which can radiate down the back of the thigh. Much like sciatica, that neuropathy can be a burning, tingling, stinging or aching sensation that extends to the back of the knee. 

Prolonged standing or walking, stair climbing, long car rides and standing up from a seated position can exacerbate symptoms. Many patients also favor one side of their buttocks when seated or have trouble sleeping on one side.  

Although SI joints are susceptible to osteoarthritis over time like any other joint, certain people are more at risk:  

• Anyone who has undergone a past lumbar fusion. Roughly half of all patients who have this surgery will develop SI issues at some point in their lifetimes, generally due to adjacent level disease.

• Middle-aged women with children. Pregnancy releases hormones that loosen and stretch the pelvis and SI joint structure in preparation for birth. Emerging pain can be result of decades of ligament laxity and abnormal movement and wear.  

• People who have experienced a traumatic injury due to a sudden impact, such as a car accident or fall. 

A physical exam and close review of symptoms are necessary to unmask SI joint dysfunction. Interventionalists also can perform a diagnostic injection, which delivers a small amount of a steroid medication or local anesthetic such as lidocaine directly into the joint via an X-ray-guided needle. Pain relief of greater than 50 percent usually will confirm a diagnosis. 

The first line of treatment generally involves anti-inflammatory medications; application of heat, ice or ultrasound; and physical therapy with stretches and movements to address muscular tightness and stabilization techniques. If SI degeneration has impacted walking gait – which can lead to knee or back pain – aquatic therapy can be very beneficial as well.  

In some patients, steroid injections can effectively calm inflammation and pain for three to six months on average. Other possibilities include radiofrequency ablation to burn sensory nerves that innervate the joint; wearing an SI joint belt, a supportive brace; or visiting a chiropractor.  

Fusion surgery with an orthopaedist is an option for severe cases that don’t respond to more conservative treatments, although my aim is to help patients avoid that step. 

Since back pain is the second-leading cause of doctors’ visits nationwide – trailing only the common cold – raising awareness of all potential pain generators is vital. I also encourage patients with unexplained pain to see a specialist who may be able to solve the puzzle.

Dr. Bradley is a Board certified and fellowship trained physical medicine and rehabilitation specialist with Hampton Roads Orthopaedics & Sports Medicine, based in Williamsburg. hrosm.com