A caudal epidural is an injection of anti-inflammatory medication into the lower part of the spinal canal, delivered through a small natural opening at the base of the tailbone called the sacral hiatus. It’s one of the most common procedures for treating lower back pain that radiates into the legs, and it works by reducing inflammation around irritated or compressed nerves near the bottom of the spine.
How It Differs From Other Epidural Injections
Most people associate epidurals with childbirth, where a needle enters the spine between two vertebrae in the lower back. A caudal epidural takes a different route entirely. Instead of going between the bones of the lumbar spine, the needle enters through the sacral hiatus, a small gap in the bone at the very bottom of the tailbone. From there, medication travels upward into the epidural space, the fluid-filled area surrounding the spinal nerves.
This approach has a practical advantage: the needle enters well below where the spinal cord ends, which reduces the risk of accidentally puncturing the membrane that holds spinal fluid. Other epidural approaches, like interlaminar injections that go directly between vertebrae, use a “loss of resistance” technique to find the epidural space. The caudal route is generally considered more straightforward in terms of needle placement, though it still requires imaging guidance to confirm the medication reaches the right area.
Conditions It Treats
Caudal epidurals are primarily used for pain that starts in the lower back and shoots down into one or both legs, a pattern caused by inflamed or pinched nerves. The most common reasons people receive this injection include:
- Herniated discs pressing on nearby nerves
- Lumbar spinal stenosis, where the spinal canal narrows and crowds the nerves
- Sciatica or radiculopathy from any cause
- Degenerative disc disease
- Spondylolisthesis, where one vertebra slips forward over another
- Failed back surgery syndrome, persistent pain after a previous spinal operation
The injection doesn’t fix the underlying structural problem. It reduces inflammation around the nerve, which in many cases is what’s actually generating the pain. This can create a window of relief that allows you to participate in physical therapy or recover from an acute flare-up.
What the Procedure Feels Like
You’ll typically lie face down on a procedure table, sometimes with a pillow under your hips to tilt the pelvis into a better position. The skin near your tailbone is cleaned and numbed with a local anesthetic. You’ll feel pressure as the needle is guided through the sacral hiatus. Most providers use fluoroscopy (live X-ray) and inject a small amount of contrast dye to confirm the needle is in the correct space before delivering the medication.
The injection itself contains a combination of a steroid to reduce inflammation and a local anesthetic for immediate, short-term numbing. The entire procedure typically takes 15 to 30 minutes, including setup and positioning.
What to Expect Afterward
There’s often a pattern to the pain relief that catches people off guard. Because the injection includes a local anesthetic, you may feel noticeably better within the first few hours. That initial relief then fades, and your original pain (sometimes with added soreness at the injection site) can return for several days before the steroid component kicks in. This lag is normal and doesn’t mean the injection failed.
On the day of the procedure, you should not drive, operate machinery, make major decisions, or drink alcohol. Light activity around the house is fine, but skip heavy lifting and manual labor. Most people return to work the next day or within a couple of days, depending on the physical demands of their job. Your provider will typically check in within two weeks to assess how well the injection worked.
How Well It Works
A retrospective study published in Orthopedic Reviews found that patients reported an average of 67% pain relief at their short-term follow-up. About 89% of patients experienced at least 50% reduction in pain, and roughly 11% reported complete relief. Only one patient in the study reported zero benefit.
Those numbers reflect short-term outcomes measured within a couple of weeks. The duration of relief varies widely. Some people get weeks of improvement, others get months. The injection can be repeated if it works well, though most providers limit the number of steroid injections per year to avoid cumulative side effects from the medication. For many people, a caudal epidural is one part of a broader treatment plan that includes physical therapy, activity modification, or other interventions.
Risks and Side Effects
Most caudal epidurals are uneventful. Common side effects include temporary soreness at the injection site, mild headache, and a brief increase in blood sugar for people with diabetes (a known effect of steroids).
Serious complications are rare but real. The FDA has issued a safety communication noting that epidural steroid injections of any type can, in uncommon cases, cause severe neurological problems including nerve injury, paralysis, stroke, vision loss, and seizures. These events are associated with all forms of epidural steroid injection, not specifically the caudal route, and the caudal approach is generally considered to carry a lower risk of some complications (like accidental puncture of the spinal fluid membrane) compared to other epidural techniques.
Infection at the injection site is possible but uncommon with proper sterile technique. Bleeding complications are a concern for people on blood-thinning medications, which is one reason your provider will review your medications before scheduling the procedure.
Who Should Not Have One
Certain conditions rule out a caudal epidural entirely: active skin infection near the injection site, signs of increased pressure inside the skull, and traumatic spinal cord injury. Your provider will also weigh the risks more carefully if you have a bleeding disorder or are on blood thinners, have very low platelet counts, significant spinal abnormalities, or cardiovascular instability. In those cases, the procedure may still be possible with extra precautions, or an alternative approach may be recommended.