Biomechanics and stability of the spine after implantation with pedicle screw and cervical vertebral screw fixation / 中国组织工程研究

ABSTRACT

BACKGROUND:From the point of view of human anatomy, the load of the spine is more. When the body moves, the range of activities, and activity are relatively large. After screws were implanted in the spine, if biomechanical properties and stability are not up to the standard, it easily leads to lack of grip force of screw and screw loosening so as to increase the incidence of complications after treatment. OBJECTIVE:To compare biomechanical properties and stability of the spine after insertion of pedicle screw and cervical vertebral screw into the spine. METHODS:100 vertebrae under human cervical spine specimens were analyzed and randomly divided into cervical vertebral screw fixation group and pedicle screw fixation group. Cervical vertebral screws and pedicle screws were implanted in lower cervical spine specimens. Electro Force 3510 material testing machine was used to test axial pul-out force, axial pul-out strength after the fatigue loading, and fixed stability. The biomechanical properties and stability were compared after two kinds of screws were implanted in the spine. RESULTS AND CONCLUSION:(1) Instantaneous pul out force and immediate pul out stiffness were significantly higher in the pedicle screw fixation group than in the cervical vertebral screw fixation group (P<0.05). (2) Fatigue pul-out strength and fatigue pul-out stiffness did not have significant differences in both groups, but statistical analysis showed significant differences (P<0.05). Fatigue pul-out strength and fatigue pul-out stiffness were significantly higher in the pedicle screw fixation group than in the cervical vertebral screw fixation group. (3) These results suggested that pedicle screw fixation after implantation in the spine provides sufficient fixation stability, has better fatigue resistance, elevates instantaneous pul-out force and fatigue pul-out strength, and presents strong stability.