A facet injection is a minimally invasive procedure that delivers a combination of numbing medication and a steroid directly into or near a facet joint in the spine. Facet joints are small, paired joints that sit along the back of the spinal column at every level, connecting one vertebra to the next. When these joints become inflamed or arthritic, they can cause significant back or neck pain. The injection aims to reduce that inflammation and, in many cases, help confirm whether the facet joint is actually the source of the pain.
What Facet Joints Do
Your spine isn’t one solid column. It’s a chain of individual bones (vertebrae) linked together by two types of joints: the intervertebral discs in front and the facet joints in back. Facet joints allow you to bend, twist, and extend your spine while keeping the whole structure stable. Each spinal level has a left and right facet joint, and like any joint in the body, they have a cartilage lining and a small capsule filled with fluid. Over time, these joints can degenerate, develop arthritis, or become inflamed from injury or overuse.
Signs That Point to Facet Joint Pain
Facet joint pain typically shows up as a one-sided or two-sided ache in the back that radiates into the buttocks, the sides of the groin, or the thighs, but stops above the knee. It tends to be worse in the morning or after periods of sitting still, and it flares with activities that arch the lower back or involve twisting. Standing or sitting for long stretches can aggravate it, and pressing directly on the joints may reproduce the pain.
The tricky part is that no imaging study, including MRI or CT, can definitively prove a facet joint is causing pain. An arthritic-looking joint on a scan may be painless, while a normal-looking joint may be the culprit. This is one reason the injection itself serves a diagnostic role: if numbing the joint eliminates your pain, it confirms that joint as the source.
Diagnostic vs. Therapeutic Purpose
Facet injections serve two distinct functions, and your doctor may use the procedure for one or both. A diagnostic injection uses a small amount of numbing medication (sometimes without any steroid) to test whether a specific facet joint is generating your pain. If you get meaningful relief within minutes, the diagnosis is confirmed. This step is especially important if a longer-lasting treatment, such as radiofrequency ablation (a procedure that heats and disables the tiny nerves feeding the joint), is being considered.
A therapeutic injection adds a corticosteroid to the numbing agent. The steroid reduces inflammation inside the joint capsule and can provide weeks to months of pain relief. In one study of lumbar facet injections, 52% of patients achieved greater than 50% pain reduction at three months. A separate study found that 65% of patients maintained significant relief for up to six months after an intra-articular injection with a local anesthetic and corticosteroid.
Facet Injection vs. Medial Branch Block
You may also hear about a medial branch block, which is closely related but technically different. A facet injection goes directly into the joint capsule. A medial branch block targets the small nerve (the medial branch) that transmits pain signals from the facet joint to your brain. The needle is placed near the nerve rather than inside the joint.
Both approaches are effective for chronic spinal pain. A recent systematic review found that facet injections produced slightly lower pain scores and higher patient satisfaction compared to medial branch blocks, though the pain difference wasn’t statistically significant. Facet injections also had fewer adverse effects overall. In practice, medial branch blocks are often used first as a diagnostic step because of their specificity in isolating facet-related pain, while intra-articular facet injections are commonly chosen when immediate pain relief and inflammation reduction are the goals.
How the Procedure Works
A facet injection is an outpatient procedure that typically takes 15 to 30 minutes. You lie face down on a table, and the doctor uses real-time imaging, usually fluoroscopy (a type of live X-ray), to guide a thin needle into the correct joint. CT or ultrasound guidance is used in some cases. Once the target joint is visualized, the skin over the area is numbed with a local anesthetic, and the spinal needle is advanced until it enters the joint capsule.
To confirm the needle is in the right place, the doctor may inject a small amount of contrast dye and watch it flow into the joint space on the screen. Once placement is verified, the therapeutic mixture is injected. The total volume going into the joint is small, typically 1 to 1.5 milliliters, because the joint capsule itself is tiny. Injecting too much can rupture the capsule. The entire injection takes only seconds once the needle is positioned.
What the Injection Contains
The injection is a combination of two medications. The first is a local anesthetic (a numbing agent similar to what a dentist uses) that provides immediate but temporary pain relief, usually lasting hours to a day. The second is a corticosteroid, an anti-inflammatory medication that takes a few days to reach full effect but can suppress inflammation for weeks or months.
A 2026 multisociety consensus recommends keeping the steroid dose modest: no more than 10 milligrams of the commonly used steroids per facet joint. In the cervical and upper back (thoracic) regions, non-particulate formulations are preferred to minimize the rare risk of blood vessel complications.
Recovery and What to Expect
You can go home the same day, usually within 30 to 60 minutes of the injection. Small bandages cover the injection site and can be removed the next day. Showering is fine the day after, and light activity around the house is encouraged right away, partly because your doctor wants to see whether the injection helps with your normal daily movements.
Expect some soreness at the injection site for a day or two. Avoid heavy lifting, intense cardio, or weight training for at least 48 hours. The numbing medication may give you immediate relief that fades within a day. If a steroid was included, the anti-inflammatory effect typically kicks in over the next several days. For some people, relief lasts only about 48 hours. For others, it persists for three to six months or longer.
Risks and Side Effects
Facet injections are considered very safe. The most common side effects are mild: temporary soreness at the injection site, minor skin reactions, and short-lived increases in pain. Steroid-related effects can include fluid retention and, in people with diabetes, a temporary rise in blood sugar levels.
Serious complications are rare but documented. These include infection (septic arthritis or abscess formation near the spine), accidental puncture of the membrane surrounding the spinal cord, and, in cervical injections, the possibility of spinal cord injury. Thoracic-level injections carry a small risk of puncturing the lung lining. Using image guidance during the procedure substantially reduces these risks compared to blind injections.
How Often You Can Get Them
There are no large-scale studies establishing exact limits on injection frequency. In practice, most providers space injections at least several weeks apart and limit the total steroid exposure over the course of a year. If a facet injection provides only short-lived relief, your doctor may recommend medial branch blocks followed by radiofrequency ablation for a longer-lasting solution. The ideal candidate for that next step is someone who got significant pain relief from the initial injection or nerve block but found it wore off too quickly.