Sacroiliac (SI) joint injections are a common procedure used to diagnose the source of lower back and pelvic pain and provide therapeutic relief. The SI joint connects the spine to the pelvis and can become inflamed or dysfunctional, resulting in significant discomfort. Patients frequently ask physicians about the pain experienced during the procedure, especially since the injection is near the spine.
The Procedure: Minimizing Discomfort
The sacroiliac joint injection process is designed to be quick and relatively comfortable, focusing on local anesthesia to manage pain. Before the main needle is inserted into the joint, the physician applies a local anesthetic, or numbing medication, to the skin and the deeper tissues. This initial step is often described as a brief pinch, similar to a bee sting, followed by a temporary burning sensation as the medication works to numb the area.
Once the local anesthetic has taken effect, the physician guides a thinner needle toward the sacroiliac joint itself. During this deeper placement, patients usually feel a sensation of pressure rather than sharp pain. The entire procedure is performed using fluoroscopy, a form of real-time X-ray guidance, to ensure the needle is positioned precisely within the narrow joint space.
Using imaging guidance allows for quick and accurate placement, which reduces the overall time the needle is in the body. After confirming the correct location with contrast dye, the therapeutic mixture of local anesthetic and corticosteroid is injected into the joint. The total time for the injection itself is generally brief, often lasting less than 20 minutes from start to finish.
Immediate Post-Injection Sensations
While the procedure itself is typically well-tolerated, new sensations and potential discomfort are common in the hours and days immediately following the injection. It is normal to feel some temporary soreness, tenderness, or minor bruising at the injection site for one to two days. This localized discomfort is a temporary reaction to the needle passing through the skin and muscle tissue.
A temporary increase in the original SI joint pain, known as a “steroid flare” or “cortisone flare,” can occur. This flare-up is believed to be caused by the body reacting to the injected steroid crystals before they dissolve and begin reducing inflammation. This increased pain can happen within hours to a few days after the injection, often after the immediate numbing effect of the local anesthetic has worn off.
A steroid flare generally peaks within the first 24 hours and subsides on its own within one to three days. To manage this discomfort, physicians often recommend applying a cold compress or ice pack to the area and may suggest taking over-the-counter pain relief medication. Patients are usually advised to avoid heavy lifting or strenuous activities for the first 24 hours to allow the medications to settle and minimize irritation.
Assessing Effectiveness and Pain Relief Timeline
The injection uses two components: a local anesthetic and a corticosteroid. The local anesthetic provides an almost immediate, temporary reduction in pain. If pain is significantly reduced within minutes of the injection, it provides a strong diagnostic indicator that the SI joint is the source of the patient’s discomfort.
The second component, the corticosteroid, is the long-acting anti-inflammatory medication intended to provide therapeutic relief. Unlike the anesthetic, the steroid does not work instantly; it typically requires three to seven days to begin reducing the inflammation in the joint. Patients are often asked to keep a pain diary to track their symptoms in the days and weeks following the procedure.
A positive therapeutic response is generally defined as experiencing substantial pain relief that lasts beyond the initial few days. The duration of relief varies widely among individuals, ranging from a few weeks to several months. This delayed timeline is a normal expectation and should not be mistaken for a failed procedure.