Lumbar Degenerative Spondylolisthesis

What it is

Spondylolisthesis means one vertebra has slipped forward on the one below it. In the degenerative type, the slip happens because the joints and ligaments that normally hold those bones in line have worn with age and loosened — the bone itself is intact. It most often occurs at the L4–L5 level and is more common in women after age 50.

What it feels like

Many people have low back pain, but the symptoms that tend to limit them most come from the slip narrowing the canal: heaviness, aching, or cramping in the legs when standing or walking, eased by sitting or leaning forward. The slip can also pinch a single nerve and send symptoms down one leg.

How we diagnose it

Standing X-rays show the slip, and bending (flexion–extension) views can reveal whether the segment is unstable — whether it moves more than it should. An MRI shows how much the nerves are crowded. Both pieces matter for planning.

How we treat it

Most people begin with non-surgical care — physical therapy, medication, and sometimes an epidural steroid injection — and many do well with it. When symptoms keep limiting you, surgery relieves the pressure on the nerves (a decompression). Because the segment is already slipping, a fusion is often added to steady it. Whether you need the fusion is the central decision here, and we make it together based on your symptoms, your imaging, and how unstable the segment is — not on the slip alone.

The science — for the curious

A degenerative slip is usually low-grade and tends to stay put rather than progress quickly. The reason a fusion is often paired with the decompression — rather than decompression alone — is the underlying instability: taking pressure off the nerves can sometimes allow an already-loose segment to slip a little more. Even so, I fuse only what truly needs it, because a fused level shifts extra load onto its neighbors and can speed their wear over time. This is one of the more individualized decisions in spine care, which is why we weigh it carefully together.

Learn more

OrthoInfo — Adult Spondylolisthesis in the Low Back: orthoinfo.aaos.org

North American Spine Society — KnowYourBack: knowyourback.org

This handout is general education about a common condition and does not replace the personalized advice we discuss in clinic. If anything here does not match what we talked about, what we talked about wins — please ask me.