Spondylolisthesis(“vertebra slipping”, in Greek) is a condition in which a vertebra shifts forward into the adjacent vertebra.
The three types of spondylolisthesis are classified by its causes: spondylolytic spondylolisthesis, degenerative spondylolisthesis, and traumatic spondylolisthesis.
Although spondylolisthesis usually affects one area, cases of multiple dislocation are not uncommon in which the vertebrae slippage resembles that of a staircase.
According to the direction of the slippage, the spondylolisthesis is referred to as anterolisthesis (forward slippage), or retrolisthesis (backward slippage). The latter condition is diagnosed with minimum of 3mm posterior displacement.