This is a procedure that is done to take pressure of your spinal nerves. The goal of the surgery is to free up the nerve that is affected and relieve the symptoms experienced.
Typically there is a disc herniation on one side of the spinal canal causing pain, numbness, weakness or a combination of these symptoms down one leg, although less commonly both legs may be involved. A “herniation” is when something comes through something else. The spinal disc sits between the bones in your spine (vertebral bodies) and acts as a cushion and gives your spine the ability to bend in different directions.
Needless to say, discs are under a lot of pressure, often above 100 pounds per square inch (your car tires have about 30 psi). Unfortunately, as we age our discs start to “degenerate”, a medical term that means “wear out.” As you can imagine a worn out disc might not be able to handle 100 psi. The disc is made up of two parts, a tough outer ring (annulus fibrosus) and a soft inner core (nucleus pulposus). Both parts wear out with age but when the annulus gives out, part of the nucleus can sneak through (herniation) and put pressure on the adjacent nerve. During the surgery, it is this piece of the nucleus that is removed, not the whole disc.
If you have only leg symptoms before this procedure then you are likely to have near complete relief after. On the other hand if you have back and leg symptoms then you may be left with back pain even if your leg symptoms have gone away. It is believed that this is because the disc is now quite abnormal, having herniated and undergone surgery. This disc will continue to degenerate and could be painful in the future.