Epidural blood patches are a medical procedure designed to alleviate severe headaches that can occur after certain spinal procedures. This treatment involves injecting a small volume of a patient’s own blood into the epidural space of the spine. The primary goal is to seal a cerebrospinal fluid (CSF) leak, which is often the underlying cause of these intense headaches. By addressing the leak, the procedure aims to restore normal pressure around the brain and spinal cord, resolving the headache.
Why a Blood Patch is Performed
An epidural blood patch is typically performed to treat a post-dural puncture headache (PDPH), also known as a spinal headache. This headache arises when the dura mater, a tough membrane surrounding the brain and spinal cord, is accidentally punctured. Such a puncture allows cerebrospinal fluid (CSF) to leak out, leading to a decrease in fluid pressure around the brain. This fluid loss can cause the brain to sag slightly, stretching nerves and tissues, resulting in a headache that usually worsens when upright and improves when lying flat.
PDPH commonly occurs after procedures like a lumbar puncture (spinal tap) or as a complication of epidural anesthesia, frequently used for pain relief during childbirth, if the epidural needle inadvertently punctures the dura. While many PDPH cases resolve on their own within days, an epidural blood patch is considered for individuals experiencing severe, persistent headaches that do not respond to conservative treatments like bed rest, hydration, or caffeine.
The Blood Patch Procedure
The epidural blood patch procedure begins with patient preparation, which includes positioning the patient, often lying on their side or seated, and cleaning the injection site on the back with an antiseptic solution. A local anesthetic may be administered to numb the skin at the injection site to minimize discomfort. Concurrently, a healthcare provider will draw a small amount of the patient’s own blood, typically around 20 milliliters, from a vein in their arm.
An anesthesiologist or radiologist then carefully inserts a thin needle into the epidural space, near the presumed site of the CSF leak. Once the needle is correctly positioned, the freshly drawn blood is slowly injected into this epidural space. Patients might experience a feeling of pressure or mild discomfort in their back, buttocks, or neck during the injection, and the injection is stopped if discomfort becomes too intense or the target volume is reached.
How the Blood Patch Works
The effectiveness of an epidural blood patch stems from a dual mechanism: mechanical pressure and biological sealing. When the patient’s own blood is injected into the epidural space, it creates an immediate increase in pressure within that area. This temporary rise in epidural pressure can help to displace cerebrospinal fluid (CSF) upwards, thereby restoring more normal pressure around the brain and providing immediate relief from the headache.
Beyond this immediate pressure effect, the injected blood begins to clot. The blood forms a fibrin clot, which acts as a “patch” directly over the hole or tear in the dura mater, effectively sealing the site of the CSF leak. This biological seal prevents further leakage of CSF, allowing the body’s natural healing processes to repair the dural puncture over time.
Recovery and Potential Outcomes
Following an epidural blood patch, patients are typically advised to lie flat for a period in a recovery area to help the patch set. Most individuals experience significant improvement in their headache symptoms immediately or within a few hours to a day. Patients are encouraged to avoid strenuous activities, heavy lifting, straining, or sudden movements for at least 24 to 72 hours to prevent dislodging the newly formed blood patch. It is also recommended to stay well-hydrated.
The success rate of a single epidural blood patch for post-dural puncture headaches is high, often ranging from 70% to 90%. If the headache persists or returns, a second blood patch may be considered, which can further increase the success rate. Some common side effects include temporary back pain or discomfort at the injection site. Less common side effects can include nerve irritation, and rare complications like infection or nerve damage are possible. Patients are advised to contact their healthcare provider if they experience increasing pain, fever, new weakness or numbness, or issues with bladder or bowel control.