surgical treatment of spondylolysis and spondylolis thesis

in our prospective,twenty patients who had symptomatic spondylolysis or grade-i or ii lytic spondylolisthesis, and whose symptoms has not been relieved by non-operative treatment,were operated upon using bucks method for bone-grafting and internal fixation of the defect of the pars interarticularis with screws,and posterolateral fusion -with or with out-decompression.