Insertion torque and pullout strength of general spine system pedicle screws in human vertebral bodies:an in vitro biomechanical study / 中华骨科杂志

ABSTRACT

Objective To measure and compare the insertion torque and pullout strength of newly designed general spine system(GSS) screws with those of SOCON and CCD pedicle screws in normal human cadaver vertebrae, and to evaluate the screw purchase of GSS pedicle screws. Methods Twenty seven lumbar vertebral bodies obtained from 6 fresh normal male cadavers were classified into 3 groups randomly, 18 pedicles per group. GSS, SOCON and CCD pedicle screws were implanted into the pedicles of each group respectively. Pedicle screws were inserted with a torque screwdriver. Each screw was extracted axially from the pedicle at a rate of 5 mm/min until failure using a material testing machine(SWD-10, Changchun, China). Force data were recorded and analyzed using a one way ANOVA. P