Dr Blackburn fills us in on the experience known as a “patchy” epidural – when it doesn’t work effectively

“The space where we site the epidural is what is called a ‘potential space’, and doesn’t exist in normal anatomy. We place our epidural needle between two layers of tissue that normally lie directly next to each other. As we inject the epidural medication, the space expands. Occasionally, there are bands of tissue that don’t allow the space to expand uniformly, so the mixture concentrates in an area and not in another area – this leads to patchiness and occasionally a unilateral block. Once we have placed the epidural, we need to confirm that it is indeed working. If it is found to be unilateral or patchy, there are a couple of things we can try: pulling the epidural catheter back a couple of millimetres usually helps as the tip of the catheter may then be free, or we can remove the epidural and reinsert it slightly higher or lower and hope for a better position. This will help in most cases.”