Spondylolisthesis occurs when one vertebra slips forward in relation to the lower vertebra, usually in the lumbar spine or low back. This condition can be congenital (present from birth), develop during childhood or happen later in life. It results from the physical stresses to the spine from lifting, sports such as football or gymnastics, accidents or general wear and tear.Another type of spondylolisthesis is degenerative spondylolisthesis, occurring usually after age 50. This may create a narrowing of the spinal canal (spinal stenosis).