Results of screw osteosynthesis in spondylolysis and low-grade spondylolisthesis.

Nineteen patients with spondylolysis and low-degree spondylolisthesis were treated with bone grafting and osteosynthesis of the pars defect with the Morscher hook screw (16 cases) or with Buck's procedure (three cases). Eighteen patients had a follow-up examination. In the age-group 9-16 years (ten patients) there were 80% excellent or good results with fusion, whereas in the adult group (eight cases) the majority had poor results. It seems that the operative techniques which we applied are useful in juvenile patients; adults require a more reliable fixation.