In the modern surgical and anesthesia era, millions of patients worldwide have been safely anesthetized with either spinal or epidural anesthesia. The theory behind these forms of anesthesia is simple: the anesthesiologist or other practitioner gains access to the adjacent nerves and anatomical region near the sac that encompasses the spinal cord and injects local anesthesia there to render the body area below that level insensitive to pain. In the case of epidural anesthesia, the numbing medication is injected superficial (more towards the surface of the body) to where the spinal fluid is, in a space called the epidural space. In the case of spinal anesthesia, the medication is delivered deeper (more anatomically beneath the surface of the body), to where the spinal fluid resides, in a space called the subarachnoid space.
But whichever type of anesthesia, spinal or epidural, the provider chooses, there is the potential to create a complication known as a post-dural puncture headache (PDPH). A PDPH is a bothersome and at times debilitating occurrence. This complication seems to be particularly more common among new mothers who delivered by C-section or had epidural for a conventional delivery. It can occur one of two ways. The first way is from an epidural anesthetic whose needle went too deeply and punctured the space that contains the spinal fluid—in the parlance of anesthesiologists, a “wet tap.” The second way PDPHs can develop are from spinal anesthesia itself. Certain people may just be prone to developing them, even when flawless technique is employed.
A PDPH is characteristic in that it disappears when the patient is lying down, only to reappear upon sitting up or standing. It can be accompanied by ringing in the ears, light sensitivity and nausea, and the headache can be most pronounced in the back of the head. It is a truly miserable experience and many patients have come to me for a certain treatment for relief that I discuss below.
Certain risk factors exist for development of PDPH from spinal anesthesia. Younger patients tend to get it more frequently and severely than older ones. Also, the type of needle used by the anesthesia provider can have a great impact on the development of PDPH. The larger the bore of the needle, the greater the chance of PDPH. That’s why you should always ask any provider, particularly if you are in your twenties or thirties, to use a needle of greater than 22 gauge; that is,request a needle of 25 or 27 gauge. The higher the number, the thinner the needle and the less chance of getting a PDPH. You’d think you would not have to ask but do so! Sometimes doctors need reminding, if you can believe that.
The type of needle is crucial as well.Ask for a Sprotte or Whitacre needle if those are available. They have a bevel design on the tip that creates a puncture whose shape is much less conducive to developing PDPHs. You see, it is the hole in the punctured membrane that can cause a continuous leak of spinal fluid and lead to the brain literally sagging in the skull, causing the headache and symptoms I’ve described. That hole usually closes on its own but in some cases stays open from a “wet tap” epidural or spinal anesthetic, leading to PDPH and its attendant miseries.
If a PDPH develops and is resistant to bed rest, fluids, caffeine (a traditional treatment option) and pain medicine, an epidural blood patch might be necessary. That is accomplished by doing an epidural and then “patching” the dural puncture hole with the patient’s own blood, which is drawn in advance from the arm. The blood creates a clot that fills and closes the hole, thereby sealing the leak. After blood patching, patients are so relieved and happy to be rid of their headache that these are some of the most grateful patients one can imagine. As I recall, all of the patients I’ve treated with a blood patch have been women.
So remember: if you are going to receive spinal anesthesia (which by the way, in appropriately chosen patients, is a great anesthetic), go for the thinnest needle, a Sprotte or Whitacre tip, and seek out the most skilled provider you can find. And do realize that even in the best of hands, epidural anesthesia can result in a “wet tap,” perhaps necessitating the blood patch “cure.”For more with Dr. Sherer, click here for his podcast and video interviews, and here to buy David’s book, Hospital Survival Guide: The Patient Handbook to Getting Better and Getting Out