An epidural blood patch (EBP) is a specialized medical procedure designed to treat a spinal headache, which is caused by a leak of cerebrospinal fluid (CSF). The technique involves using the patient’s own blood, known as autologous blood, as a natural sealant. A small volume of this blood is injected into the epidural space near the spinal cord. This action forms a clot, which physically seals the tear in the protective membrane, stopping the CSF leakage. The procedure is a highly effective way to restore the normal fluid pressure around the brain and spinal cord.
Why a Blood Patch is Necessary
The epidural blood patch treats a Post-Dural Puncture Headache (PDPH), commonly known as a spinal headache. This type of severe headache is a consequence of a dural puncture, which is a small hole or tear in the dura mater, the tough membrane that encases the spinal cord and the surrounding CSF. When a hole is created, the CSF, which acts as a protective cushion for the brain and spinal cord, begins to leak out into the surrounding epidural space.
This leakage causes a drop in fluid pressure around the brain, leading to a state called intracranial hypotension. The characteristic feature of a PDPH is that the headache is intensely painful when the person sits or stands upright, but it is often completely relieved when they lie flat. This positional nature is a direct result of the brain dropping slightly within the skull due to the lack of fluid support.
A dural puncture can occur intentionally during a diagnostic lumbar puncture, also called a spinal tap, or accidentally during an epidural injection, such as those given during labor. While many PDPH cases resolve spontaneously within a week or two, the pain is often debilitating. When conservative treatments like bed rest, hydration, and caffeine fail to provide relief, the epidural blood patch becomes the standard and most effective treatment.
Performing the Procedure
The epidural blood patch requires sterile conditions and is typically performed by an anesthesiologist or a specialist in pain management. The process involves two concurrent steps: the drawing of the patient’s blood and the subsequent injection near the site of the CSF leak. The patient is positioned either sitting up or lying on their side, and the skin over the injection site is thoroughly disinfected.
While the injection site is prepared, a second provider draws 10 to 20 milliliters of venous blood from the patient’s arm. The blood must be handled with strict sterility to prevent any contamination. The time between drawing the blood and injecting it is minimized to ensure the blood remains fresh and does not clot prematurely.
An epidural needle is then inserted into the epidural space, the area just outside the dura mater, near the original puncture site. Imaging guidance, such as fluoroscopy, may be used to confirm the precise needle placement in difficult cases. Once the needle is correctly positioned, the collected blood is slowly injected into the epidural space over approximately 30 to 60 seconds.
The injected blood acts as a temporary plug and pressure buffer. It spreads out to cover the dural tear, and the clotting cascade quickly begins, forming a solid seal over the hole. This physical “patch” prevents further CSF leakage, immediately restoring normal fluid pressure. The patient may feel pressure or cramping in the back or leg during the injection; the injection is stopped if this discomfort becomes excessive.
Recovery and Potential Complications
Following the procedure, the patient is required to lie flat for one to two hours. This period helps the blood clot solidify and allows spinal column pressure to stabilize. Many patients report experiencing immediate relief from the severe positional headache, though for others, improvement may occur gradually over the next day.
Patients are advised to avoid strenuous activities, heavy lifting, or straining for the first 24 to 48 hours. Minor side effects are common, with many people experiencing temporary back pain or stiffness at the injection site for a few days. Some may also notice a mild, transient headache or discomfort.
The epidural blood patch is highly effective, with success rates often reaching 70% to 90% after the first attempt, but potential complications exist. Less common risks include nerve root irritation, which may cause temporary leg pain, or the rare possibility of infection. If the initial patch fails to resolve the headache, a repeat procedure may be offered, which has an even higher success rate.