Spondylolysis and Spondylolisthesis
Spondylolysis is a defect in the pars interarticularis of the vertebra. This defect usually involves the L5 vertebra (95%) . “Spondylo” derives from the Greek word for vertebra, and “lysis” refers to a defect  (see Fig. 148.1).
Spondylolisthesis is defined as a forward slip of the vertebrae relative to the one below with or without an accompanying pars defect. “Olisthesis” is the Greek word for slippage . The displacement of the vertebra could be secondary to one of the following: a congenital defect, spondylolysis (isthmic spondylolisthesis), degeneration of facet joints and/or intervertebral disk degeneration (degenerative spondylolisthesis), trauma, or pathologic .
Only a subset of patients with spondylolysis will have progression to spondylolisthesis if bilateral defects are present .
KeywordsWiltse classification Isthmic spondylolisthesis Degenerative spondylolisthesis Anesthetic management of spondylolysis and spondylolisthesis Pars interarticularis defect