[Stability of pedicle screws in comparison to anterior vertebral body screws after kyphoplasty augmentation]. / Stabilität von Pedikelschrauben versus ventral eingebrachter Schrauben nach Kyphoplastie-Augmentation.

ABSTRACT

AIM: Aim of the study was to compare stability of pedicle screws and ventral implanted screws after insertion in soft or cured kyphoplasty cement. METHODS: Pedicle screws were inserted in a total of 40 thoracolumbar vertebrae of 10 different formalin-fixed human specimens each 10 pedicle screws were implanted in soft (group 1) and cured cement (group 2), each 10 ventral screws were placed in soft (group 3) and cured (group 4) cement. Pedicle screws were then evaluated for biomechanical axial pullout resistance. RESULTS: Mean pull-out force was 452 N (range 60-1 125 N) in group 1, 367 N (range 112-840 N) in group 2, 364 N (range 65-875 N) in group 3 and 271 N (range 35-625 N) in group 4. CONCLUSION: Implantation of pedicle screws and ventral implanted screws in soft and cured kyphoplasty cement is a sufficient method. We achieved more stability with pedicle screws compared with ventral implanted screws in soft and cured cement. No significant difference was seen.