surgery on the body below the waist can be done under general or regional anaesthesia.
for general anaesthesia, the patient is rendered completely unconscious & largely pain-free till the surgery is complete.
for regional anaesthesia, only the part of the body below the waist is anaesthesised. the patient remain awake but lower body is immobile & pain-free. operations suitable for this technique include C-section, haemorrhoids & lower limb surgery. (read here)
if you are young & healthy, there's not much to choose between the 2 techniques but as the co-existing medical problems like hypertension or diabetes occur with advancing age, it may be (but not necessarily always) safer to have the surgery done under regional anaesthesia. this is largely due to the fact that regional anaesthesia interferes with body function (eg. heart, respiration) to a lesser degree compared to general anaesthesia.
take C-section as an example. everything else being equal, it is inherently safer for the mother to have a regional (in this case, spinal) anaesthesia because it removes the risk of having gastric contents enter the lungs, which is a possible & dangerous outcome if the mother was rendered unconscious by general anaesthesia. besides, being awake at the time of delivery provides the mother with the precious opportunity to hear the baby's cries & be bonded by physical contact.
but here's the deal - very few private doctors will tell their patients that it costs less, up to RM500 & sometimes beyond, to have a spinal instead of general anaesthesia. this is because fewer medication & equipment are required for the former.
so now you know.
PS. however i must put it on record that regional anaesthesia may NOT be appropriate in all operations below the waist. you need to discuss this with your doctor before making a decision.