Back surgery is done for a variety of reasons, to correct deformity, reduce and fix a fracture or remove a tumour for example but surgery to eliminate leg and back pain is often done for one of three common conditions. It generally follows a period of non-operative care that has failed to resolve the problem.

Here’s what you need to know about the most common reasons for which back surgery is suggested and about three common procedures offered to patients with back and back-related leg symptoms:

Reason: Disc herniation
This condition—sometimes called disc protrusion, prolapsed disc or (incorrectly) a slipped disc—occurs when one of the soft discs between the vertebrae in the spinal column begins to fail. Disc bulges are common and usually don’t cause trouble. But when the outer shell fails rapidly and the material inside the disc begins to extrude the body reacts with an extreme chemical reaction that inflames the nearby nerve root and causes severe leg dominant pain, sometimes with associated muscle weakness. Pressure from the bulge just makes things worse, like pressing on a boil. The surgery most commonly done for people with a disc herniation causing persistent leg pain is to remove the bulging part of the disc (See Discectomy).

Reason: Spinal stenosis
Spinal stenosis is the name given to a narrow spinal canal. Some people are born with a tight tunnel but more often it develops in older people as the bone around the spinal facet joints continues to enlarge. The extra bone narrows the tunnel and reduces the space available for the nerves. The pressure on the nerves interferes with their normal blood supply. Choking the nerves causes leg pain, worse when the muscles are used (as in walking) and better when the back bends forward (as in sitting), which increases the space between the bones. The complaint of intermittent leg pain with walking is called “neurogenic claudication” and it is something that affects a large segment of the population over age 65. The surgery most commonly done for people with spinal stenosis causing neurogenic claudication is to enlarge the spinal canal, giving the nerves more room and restoring their normal circulation. (see Decompression surgery).

Reason: Spondylolisthesis
This condition (pronounced “spon-dill-o-liss-thee-sis”) occurs when one vertebra in the spine actually slides out of place. This can happen for a number of reasons all involving the joints that link the vertebrae together. In younger people, there may be an anatomical defect or an unhealed fracture. In older people, particularly woman, degeneration may wear away part of the joint and allow it to slip apart.

The bones don’t usually slide very far, but they can shift enough to change the spinal mechanics and cause serve back dominant pain. When the slip traps a nerve root the person feels leg pain as well and this often becomes the major problem.
The surgery most commonly done for people with spondylolisthesis is to enlarge the area around a trapped nerve and either restore the slipped vertebra to its normal position or stabilize it where it is.