Spondylolysis repair using a pedicle screw hook or claw-hook system. ―a comparison of bone fusion rates―

INTRODUCTION: To assess the bone fusion rates and clinical results of two surgical methods (pedicle screw claw-hook fixation and pedicle screw hook fixation) of lumbar spondylolysis repair. METHODS: A multicenter database of surgical patients with lumbar spondylolysis was reviewed. All patients < 20 years old with a minimum of 6 months of follow-up and computed tomography images were included. Operation time and blood loss amount were investigated. Visual analogue scale (VAS; 0-10) scores for lower back pain were evaluated to assess clinical results. RESULTS: A total of 17 patients met the inclusion criteria. Pedicle screw hook fixation was performed in five patients (the hook group), and pedicle screw claw-hook fixation was performed in 13 patients (the claw-hook group). One patient was included in both groups because each method was performed at different lumbar levels (L4 and L5). The bone fusion rates at 3, 6, and 9 months after surgery were significantly higher in the claw-hook group than those in the hook group. Operation time and blood loss amount were not significantly different between the groups. VAS scores improved in the claw-hook group but not in the hook group because of a small number of patients. CONCLUSIONS: Pedicle screw claw-hook fixation was more effective than pedicle screw hook fixation in terms of bone fusion rates.