A systematic review of the literature was performed to establish whether direct repair of the pars defect or intervertebral fusion achieves better Oswestry Disability Index scores in adolescent spondylolysis or low-grade spondylolisthesis. Nine studies fulfilled the inclusion criteria, reporting a minimum total of 80 direct repairs and 108 fusions because of presumed replication of data between studies. Little statistically or clinically significant difference could be established between the two interventions. The only comparative study showed improved long-term outcome with fusion. Further well-designed prospective comparative studies are required to establish the optimum treatment for this condition
