A sacroiliac orthosis, often called an SI belt, is a device designed to stabilize the pelvic region and alleviate discomfort originating from the sacroiliac joints. These belts are made from elastic or similar materials, are four to eight inches wide, and wrap snugly around the hips to provide compression.
How a Sacroiliac Orthosis Functions
The sacroiliac joints connect the sacrum, the triangular bone at the base of the spine, to the iliac bones of the pelvis. These joints transfer the load of the upper body to the lower limbs and act as shock absorbers for the spine. Strong ligaments encase these joints, preventing excessive motion. When these ligaments become loose or injured, the joint can move more than it should, leading to instability and pain.
An SI orthosis works by providing external compression across the pelvis. This compression acts similarly to the natural ligaments, adding stability and limiting the small, irritating movements within the joint that can cause inflammation. By cinching the pelvic ring together, the belt helps maintain proper alignment and reduces stress on strained ligaments, promoting an environment conducive to healing.
Conditions That May Benefit
A sacroiliac orthosis is recommended for sacroiliac joint dysfunction. This condition arises from abnormal motion in the SI joint, either too much or too little, which can lead to pain in the lower back, hips, and legs. The belt helps manage this pain, especially during activities like manual labor.
Pelvic girdle instability is another reason for using an SI belt. During pregnancy, hormonal changes cause ligaments to relax, leading to joint laxity and pain. An SI belt provides support to compensate for this looseness. People who have experienced trauma or sports injuries affecting the pelvic region may also find the device provides relief.
Proper Application and Use
Correct placement is necessary for the orthosis to be effective. The belt should be worn low across the hips, not high around the waist like a typical back brace. Position the bottom edge of the belt to align with the bony prominences at the front of your hips, known as the anterior superior iliac spines (ASIS). This positioning ensures the compressive force is applied directly to the pelvic ring and SI joints.
The belt should be snug and supportive but not overly constrictive, limiting joint motion while remaining comfortable during activities. You should be able to fit your fingers between the belt and your body. Over-tightening can be counterproductive and uncomfortable.
The duration of use depends on your specific condition and a healthcare provider’s recommendation. The belt is worn during weight-bearing activities that trigger pain, like walking or lifting. It is not intended for continuous wear and is not recommended for use while sleeping unless specifically advised. Follow the guidance of a physical therapist or doctor to ensure proper use.