Spondylolysis and Spondylolisthesis

Spondylolysis is a condition in which the there is a defect in a portion of the spine called the pars interarticularis (a small segment of bone joining the facet joints in the back of the spine). With the condition of spondylolisthesis, the pars interarticularis defect can be on one side of the spine only (unilateral) or both sides (bilateral). The most common level it is found is at L5-S1, although spondylolisthesis can occur at L4-5 and rarely at a higher level.

Spondylolysis is the most common cause of isthmic spondylolisthesis, in which one vertebral body is slipped forward over another. Isthmic spondylolisthesis is the most common cause of back pain in adolescents; however, most adolescents with spondylolisthesis do not actually experience any symptoms or pain. Cases of either neurological deficits or paralysis are exceedingly rare, and for the most part it is not a dangerous condition. The most common symptom is back and/or leg pain that limits a patient’s activity level.