Maximum extraction force of a cement-reinforced transsacral-2-sacral-wing screw

Abstract

Abstract Purpose To measure the maximum extraction force of cement-reinforced transsacral-2-sacral-wing screw fixation and to investigate the effectiveness of this internal fixation method.Methods Five adult cadaver specimens fixed with formaldehyde solution and moistened, as well as six fresh frozen cadavers, were utilized for this study. Three types of sacral screws were randomly placed on both sides of the same cadaveric specimen, including: (1) trans-sacral 2 sacral wing cement-reinforced screws (group S2); (2) S1-pedicle screws (group S1); and (3) sacral 2 sacroiliac screws (group S2AI). The immediate maximum extraction force values of the sacral screws in the three groups were recorded by applying axial extraction force to the screws. Statistical analysis was performed using ANOVA in SPSS 19.0, and statistical significance was set at P < 0.05. These findings provide insights into the biomechanical properties of sacral screws and could have implications for clinical applications.Results The maximum axial extraction force of the screws in group S2 was (521.80 ± 98.98) N; in group S1 was (843.16 ± 107.64) N; and in group S2AI was (536.04 ± 145.78) N. The results revealed that the maximum axial extraction force in group S1 was significantly stronger than that in groups S2 and S2AI (P < 0.001). In contrast, the maximum axial extraction force in groups S2 and S2AI was not significantly different (P > 0.05). Furthermore, in formaldehyde-fixed specimens, the maximum axial extraction force was significantly stronger in the S1 group than in the S2 and S2AI groups (P < 0.001), and in the S2 group than in the S2AI group (P < 0.05). Similar results were obtained in freshly frozen cadaveric specimens, where the maximum axial extraction force in group S1 was significantly stronger than that in groups S2 and S2AI (P < 0.001), and there was no significant difference between groups S2 and S2AI (P > 0.05).Conclusion In formaldehyde-fixed cadaveric specimens, the maximum axial extraction force of cement-reinforced transsacral-2-sacral-wing screw fixation was lower than that of S1-pedicle screw fixation, but higher than that of sacral 2 sacroiliac screw fixation. However, in freshly frozen cadaveric specimens, the difference in maximum extraction force between the S2 and S2AI groups was not statistically significant. Biomechanical experiments demonstrated that cement-reinforced transsacral-2-sacral-wing screws exhibit a significant effect on anti-pullout force performance, and may offer strong distal fixation. These screws may be an alternative to provide an effective force for spinal pelvic fixation.