An epidural blood patch is a minimally invasive procedure that uses autologous blood in order to close one or many holes in the dura mater of the spinal cord, usually as a result of a previous lumbar puncture. The procedure can be used to relieve post dural puncture headaches caused by lumbar puncture (spinal tap). A small amount of the patient's blood is injected into the epidural space near the site of the original puncture. This results in the blood clot "patching" the meningeal leak.