Sacroiliac Joint Pain

What is sacroiliac joint pain?

The sacroiliac (SI) joint is formed between the sacrum, the spinal segment inferior to the lumbar spine, and the ilium (back of the pelvis). This joint moves very little, typically only a few millimeters; however, its primary role is that of force transmission or offloading. Forces that may be transmitted from the lower limb up the spine, the spine to the lower limb, or around the pelvis may be managed by the SI joint. When the capacity of the joint to bear load or force is exceeded, this may manifest as pain and discomfort.

What causes sacroiliac joint pain?

The most common causes of SI joint pain may include excessive biomechanical stress, trauma, pregnancy, and sports injuries. Less commonly, spondyloarthropathies (e.g. ankylosing spondylitis), infection, or tumors/malignancy may be a source of SI joint pain. It should also be noted that patients who have previously undergone lumbar fusion surgery are at an increased risk of developing SI joint pain.

How is sacroiliac joint pain diagnosed?

The diagnosis of SI joint pain is primarily a clinical diagnosis. In other words, it is based on the patient’s symptoms and physical examination findings. Typically, a patient with SI joint pain will present with low back/buttock pain which can occasionally be referred to the thigh, hip, groin, or calf. On physical examination, these patients will experience reproduction of their pain with multiple provocative maneuvers. In the end, the gold standard method of diagnosis for SI joint pain is patient response to diagnostic injection such as an intra-articular SI joint injection or sacral lateral branch blocks.

How is sacroiliac joint pain treated?

Initial treatment options for management of SI joint pain may include medications, physical therapy, and/or chiropractic. In many cases, these conservative measures will allow for good recovery. If a patient is still experiencing significant pain despite the aforementioned treatment options, a SI joint injection with a combination of local anesthetic (numbing medication) and corticosteroid (cortisone or anti-inflammatory medication) can be considered as the next step in the treatment pathway. Alternative interventional options may include radiofrequency ablation (RFA) of sacral lateral branch nerves or SI joint platelet-rich plasma (PRP) injections.

Sacroiliac Joint Injection

Using x-ray (fluoroscopic) guidance, a needle is guided into the SI joint. Once the needle is in the joint, a solution of corticosteroid, an anti-inflammatory medication, and local anesthetic, a “numbing” medication, is instilled through the needle and into the joint with the goal of decreasing the pain and improving function. If the patient experiences a significant improvement in pain during the time the local anesthetic is blocking the painful joint, it can be determined with increased certainty that the SI joint is the primary source of pain. Then, the corticosteroid helps to decrease inflammation and provide longer lasting improvement in pain.

Sacral Lateral Branch Blocks and Radiofrequency Ablation

When a person’s SI joint is emanating pain, the sacral lateral branch nerves will sense this pain signal and transmit it along a pathway to the spinal cord and up to the brain where we interpret and “feel” that painful sensation. As such, lateral branch nerve blocks can be used as a diagnostic injection to help determine whether or not the SI joint is the primary source of pain. Using x-ray (fluoroscopic) guidance, needles are safely guided to and placed near the lateral branch nerves which are then anesthetized, thus temporarily blocking the pain coming from the SI joint. Patients are then asked to monitor their pain during the time period that the local anesthetic is blocking the SI joint pain. In patients who experience a significant improvement in their pain, it increases the likelihood that the SI joint is the main source of pain and radiofrequency ablation (RFA) can then be performed as a treatment to provide long lasting improvement in the pain. In patients who do not experience much improvement in their pain during the anesthetic phase, it can be determined with much more certainty that the SI joint is not the main source of the pain and the focus can shift to other potential pain generating structures.

After a patient has undergone sacral lateral branch nerve blocks to more precisely determine that the SI joint is the primary source of pain, radiofrequency ablation (RFA) can then be performed. With RFA, the needle tip is placed in close proximity to the lateral branch nerve (the nerves that supply sensation to the painful SI joint). The needle tips are then warmed up to a temperature that causes coagulation or “cauterization” of the lateral branch nerve. This disrupts the nerves that sense the pain coming from the SI joint and, consequently, disrupts the pathway for that pain to be sensed and transmitted to the brain. In the end, RFA can provide long lasting improvement in SI joint pain, typically 6-12 months at a time, and repeat RFA procedures can be performed time and again to allow for ongoing pain relief for patients.

Platelet Rich Plasma (PRP) injection