Upated July 26, 2017 Josephine There is a difference between a spinal and an epidural which I will endeavour to explain. Spinal Here the anaesthetic drug is injected into the spinal fluid but towards the end of the cord - about L4/5. The drug is administered as a one shot and since it lasts about 4-6 hours. Epidural In an epidural, the drug is injected into the space outside the dura. The dura is the membrane that surrounds the spinal cord and contains the cerebral-spinal fluid. Hence the term 'epi' dural meaning close to the dura. Sometimes a very fine catheter is placed in this spot and taped up the patient's back to be accessed at the shoulder where top-ups can be administered and is therefore suitable for procedures that might take several hours. The effect in both is the same, numbness which is generally as high as T7 (7th thoracic vertebra) which is just under the breasts. Since this has a potential impact on the diaphragm, patients must stay under close supervision in recovery until the level reduces to around T12 when respiration is no longer compromised. That's why the nurses regularly check the level of sensation using a cold spray. Headaches Headaches from spinals are quite rare though headaches from epidurals are a little more common. This is because in an epidural, the needle and cannula goes into the cerebrospinal fluid. On occasion there can be some CF loss which inevitably lowers the pressure inside the ventricles (fluid spaces) in the brain and this is what causes the headaches. Spinals don't enter the CF space so CF loss doesn't happen and therefore neither do the headaches.