Definition of Spondylolisthesis:

Spondylolisthesis is a condition in which a bone (vertebra) in the lower part of the spine slips forward and onto a bone below it.

Causes, incidence, and risk factors:

In children, spondylolisthesis usually occurs between the fifth bone in the lower back (lumbar vertebra) and the first bone in the sacrum area. It is often due to a birth defect in that area of the spine.

In adults, the most common cause is degenerative disease (such as arthritis). The slip usually occurs between the fourth and fifth lumbar vertebrae.

Other causes of spondylolisthesis include stress fractures (commonly seen in gymnasts) and traumatic fractures. Spondylolisthesis may occasionally be associated with bone diseases.