T. R. Pitzen, S. Zenner, D. Barbier, T. Georg, W. I. Steudel


March 2004, Volume 13, Issue 6, pp 524 - 529 Original Article Read Full Article 10.1007/s00586-004-0685-5

First Online: 27 March 2004

The objective of the study was to investigate the influence of bone cement, length of burr hole and bone density on pullout force and insertional screw torque of cervical spine facet screws. Both facets of 24 human cervical vertebrae were scanned for bone mineral density (BMD) and assigned to two groups for measuring of insertional screw torque and pullout strength. Maximal insertional screw torque was measured and removal of the screws was performed in displacement control (0.25 mm/s) without bone cement (PMMA), with 0.1 ml of PMMA and with the burr hole completely filled with PMMA. Screw torque was 59.1 N cm (±25.7 N cm), pullout force was 382.8 N (±140.5 N) without PMMA. Injection of 0.1 ml PMMA did not change significantly both screw torque (p=0.73) and pullout (p=0.129). Filling of the burr holes with PMMA increased significantly both screw torque (p


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