How does a spinal block differ from an epidural?
Below where your spinal cord ends, there is a sac of spinal fluid. If we inject medication (local anesthetic +/- opiate) into the sac of fluid, that’s a spinal. If we inject medication into the space just outside of that sac, it’s an epidural. Spinals use about 1/10 of the volume of drug, and a much smaller needle. The needles we use now have special points on them to reduce the chance of a post dural puncture headache (spinal headache). The blocks work faster and we usually get a denser block with the spinal. They are technically easier to do. Epidurals offer the advantage of being able to place a catheter into the epidural space to allow repeated injections or infusions of medication into that space. (We did that with spinals for a while, but there were complications so catheters are rarely used now.) This makes them a good choice when we don’t know how long the anesthetic needs to last (such as with labor and delivery) or for post-operative pain control. We can also use dilute solut
