Sciatica is pain running from the buttock to the thigh, then to the leg and into the foot associated with numbness and pins and needles (paresthesia). The distribution of the pain tells us which nerve is being compressed - see picture. It is due to pressure on one of the nerves making up the sciatic nerve, usually the fifth lumbar (L5) or first sacral nerve (S1). L5 pain runs down the side of the leg onto the top of the foot while S1 pain extends down the back of the thigh to the calf then onto the side of the foot. The S1 root supplies the ankle reflex which may be reduced or absent if the nerve is compressed. If the pain is not well localized to one particular nerve it may mean more than one nerve is affected or that is a referred pain.
Sciatica due to compression of a nerve by a disc prolapse (often called slipped disc) can and often does get better without surgery. Surgery is considered when the pain is severe and showing no improvement after six, eight or more weeks or if there is increasing weakness or if there is pressure on the nerves to the bladder. When the pain is very bad there is support for surgery but at times the pain is not too bad but just won’t go away - here the decision to operate is not so easy.
Fortunately, the operation is not a major one and the major "risk” is that it can happen again.