What does bilateral L5 with par defects mean?

Defect of spine. A pars defect of the lumbar spine involves a part of a vertebra called the pars interarticularis. " A defect in the pars is a break in this portion of bone. This break leads to a separation of the upper, front portion of the vertebra from its lower, back portion. This condition is a precursor to another condition called spondylolisthesis, which allows slipping of a vertebra in relation to the vertebrae above or below it. Previously, it was assumed that pars defects were congenital anomalies, or birth defects. Today, we understand that most pars defects are really stress fractures that usually occur in the spines of young people. The presumed cause is repeated hyperextension.
Pars defect. The pars is a brdige between the upper and lower part of the vertebrea. A pars defect is a stress fracture in the arch between the facet joints of the spine . it is also called spondylolysis it is a common cause of LBP.Treat by PT brace surgery https://www.hss.edu/conditions_spondylolysis- pars-fracture-spine.asp http://www.massgeneral.org/ortho-childrens/conditions-treatments/spondylolysis.aspx.