Repair of pars defects and spondylosis

Defects of the pars interarticularis are predominantly an acquired condition, most often occurring at the L5 level and increasing in prevalence from adolescence to adulthood. On plain lumbar x-rays, the "scotty dog” sign can be diagnostic in 95% of spondylolysis cases. Pars defects can result in debilitating mechanical back pain and degenerative changes that predispose to the development of spondylolisthesis. In the absence of a mobile spondylolisthesis, operative management is indicated in cases of neurological compromise or those who have failed extensive conservative management including reduced activities that promote hyperextension and load bearing. Direct pars defect repair can be performed using pedicle screws attached to sublaminar hooks, Buck’s procedure of laminar screw placement through the defect into the ipsilateral pedicle, and wire fixation.