Imaging predictors of progression of lumbar spondylolysis to spondylolisthesis: a systematic review

Isthmic spondylolisthesis (IS) is defined as the anterior translation of one lumbar vertebra relative to the next caudal segment as a result of a unilateral or bilateral fracture of the pars interarticularis. These fractures are interchangeably known as "pars defects" or "spondylolysis." Many risk factors have been proposed to explain the progression of a spondylolytic defect to IS, however, none are validated.