A blood patch is a medical procedure used to treat a condition called spinal headache, which can occur after a lumbar puncture or spinal surgery. During the procedure, a small amount of the patient's own blood is drawn and then injected into the epidural space of the spine. This helps to seal any leaks of cerebrospinal fluid, which can cause the headache. The injected blood forms a clot that acts as a barrier, reducing the pressure on the surrounding nerves and tissues. Most patients experience relief from their symptoms within a short time after the procedure, making it an effective treatment option for spinal headaches.