Lumbar isthmic defects in teenagers resulting from stress fractures.

Background Context: An accepted classification of spondylolysis exists. However, etiology remains controversial. There are several reports supporting acquired stress fractures in the etiology of this condition, although radiographic evidence of an acquired fracture in a given individual is very rare.

Purpose: To present evidence of development of pars defects during the teenage years.

Study Design/setting: Retrospective review of charts.

Patient Sample: Two case studies.

Methods: Charts and X-rays were reviewed to look for radiographic evidence of development of pars defects in patients who were ultimately found to have spondylolisthesis or spondylolysis.

Results: Two cases were found that demonstrated development of a pars fracture. Both patients had radiographic evidence that these fractures developed during their teenage years. Both were active individuals with a consistent level of participation in athletics.

Conclusions: Although development of pars defects may be multifactorial, these two cases support the concept that these fractures can be acquired lesions resulting from repetitive stress injury. They also demonstrate that isthmic defects can arise in teenagers, in these cases in an athletic population.